System and method for monitoring a workstation remotely

Abstract

The invention relates to a system and a method that allow a workstation (A.1, A.2) to be monitored remotely. A monitoring unit for the workstation comprises a camera (2.1, 2.2, 2.3), a gas measuring device (1.1, 1.2, 1.3, 1.4) and a workstation computer (3.1, 3.2). The system furthermore comprises a communication unit (10) and a control centre having a central output computer and an output unit. Signals from the camera (2.1, 2.2, 2.3) and the gas measuring device (1.1, 1.2, 1.3, 1.4) are transferred to the workstation computer (3.1, 3.2) by cable or wirelessly and from there on to the communication unit (10) by cable or wirelessly. The signals are transferred from the communication unit (10) to the central output computer wirelessly. The central output computer causes the received signals to be output on the output unit in a form that is apparent to a human being. The data connection between the communication unit (10) and the central output computer is preferably routed via a public mobile radio network.

Description

[0001] System and method for remotely monitoring a workplace

[0002] Description

[0003] The invention relates to a monitoring system and a monitoring method for remotely monitoring at least one workplace during a period in which at least one person is performing work at the workplace, at least temporarily. Harmful gases may escape and other events dangerous to humans may occur at this workplace.

[0004] The invention is based on the object of providing a monitoring system and a monitoring method that enable the remote monitoring of at least one workplace. At least one person performs work at or in this workplace. Hazardous substances that are hazardous to humans can be released at the workplace. The monitoring system and the monitoring method should be able to be set up relatively quickly.

[0005] The object is achieved by a monitoring system having the features of claim 1 and by a monitoring method having the features of claim 24. Advantageous embodiments of the monitoring system according to the invention are, where appropriate, also advantageous embodiments of the monitoring method according to the invention and vice versa.

[0006] The monitoring system according to the invention and the monitoring method according to the invention make it possible to remotely monitor at least one workstation. Preferably, at least two workstations can be remotely monitored simultaneously using the monitoring system according to the invention and the monitoring method according to the invention. The monitoring system according to the invention comprises at least one monitoring unit for the or each monitored workstation, optionally at least two monitoring units for at least one monitored workstation. The or each monitoring unit comprises

[0007] - at least one camera, optionally at least two cameras,

[0008] - at least one gas measuring device, optionally at least two gas measuring devices, and

[0009] - a signal processing workstation computer.

[0010] The or each camera of a monitoring unit is capable of generating an image signal from the monitored workstation. The image signal shows the workstation in full or at least in part and preferably comprises a sequence of images, in particular a video sequence, from the workstation. The or each camera is preferably designed to generate the image signal during the entire period in which the workstation is being monitored. It is possible for the monitoring system to comprise at least two cameras, with these two cameras each generating an image signal from the same workstation in one application and image signals from two different workstations in another application. A camera, a gas measuring device, and the workstation computer of a monitoring unit can each be arranged in the workstation or outside the workstation.It is possible that a camera and / or a gas detector are located in the workplace and another camera and / or another gas detector are located outside the same workplace and the latter generates signals from the workplace from outside.

[0011] The or each gas measuring device of a monitoring unit is capable of measuring the concentration of at least one target gas that occurs or can occur in or at the monitored workplace. Optionally, the or at least one gas measuring device is capable of simultaneously measuring the respective concentrations of at least two target gases. The or one target gas is in particular a flammable or toxic gas or another gas that is harmful or dangerous to humans. It is also possible for the gas measuring device to measure whether the oxygen concentration at the workplace is sufficiently high. In a first alternative, the or each gas measuring device at a workplace is capable of comparing a measured target gas concentration with a predetermined concentration limit.In a second alternative, a target gas concentration measured by a gas measuring device at a workplace is transmitted to the workstation computer of the monitoring unit for that workplace, and the workstation computer compares the target gas concentration with the concentration limit. If the measured target gas concentration is above the concentration limit or generally outside a specified value range, the gas measuring device (first alternative) or the workstation computer (second alternative) can automatically generate an alarm and trigger transmission of the alarm to a remote recipient. It is also possible for the alarm to be triggered if the target gas concentration is below the concentration limit. One example of this is the oxygen concentration at the workplace, which must not fall below a specified limit.

[0012] It is possible, but thanks to the invention not required, for a human to compare the measured target gas concentration with the concentration limit and trigger an alarm. Furthermore, it is possible, but thanks to the invention not absolutely necessary, for the central output computer or an optional central computer to receive a signal with the measured target gas concentration from the monitoring unit and apply a decision rule to this signal in order to generate an alarm. This possible embodiment would require a measured target gas concentration to be transmitted from the monitoring unit to the first central station. The invention makes it possible to transmit a measured target gas concentration to the first central station, but eliminates the need for such data transmission. The invention therefore saves data traffic, in particular data traffic from the first central station to a monitoring unit.

[0013] It is also possible for both the alarm and a message containing the measured target gas concentration, optionally including the type of detected target gas, to be transmitted to the first control center. Because the monitoring unit generates the alarm, it is possible to transmit the alarm to the first control center with a higher priority than the target gas concentration. This configuration is particularly advantageous when a public mobile network is used to transmit messages from the communication unit to the first control center. The message containing the target gas concentration makes it easier for an operator at the first control center to assess the situation at the workstation where the alarm was triggered.

[0014] If the central output computer or an optional central computer were to apply a decision rule to the measured target gas concentration, it would be necessary to store the decision rule in the central output computer or the optional central computer and keep it up to date. In particular, it would generally be necessary to maintain an upper limit value for a harmful target gas and / or a lower limit value, for example, for the oxygen concentration. There would be a risk that the decision rule might not be up to date or that no decision rule is available at the central computer for a gas measuring device in use. The invention thus reduces the risk that a target gas might not be detected or that a false alarm might be generated.

[0015] In one embodiment, at least one gas measuring device itself or the monitoring unit for the monitored workplace issues an alarm. In this embodiment, the alarm is thus issued both in or at the workplace and in the first control center. The output at the workplace and the output in the first control center are based on the same target gas measurement and the same concentration threshold. The invention eliminates the need to transmit a signal containing the target gas concentration to the central output computer or the optional central computer and then, conversely, to transmit an alarm back to the workplace. This generates additional data traffic and can lead to a time delay.

[0016] It is possible for a worker to carry the gas measuring device(s) with them at the workplace while carrying out work at the workplace. Preferably, however, the gas measuring device(s) is(are) fixed in place at a workplace, at least for as long as the workplace is monitored according to the invention. This enables the gas measuring device to measure a target gas concentration in an area of ​​the workplace even if no person with a gas measuring device is currently in this area. In particular, it is possible to warn a person in good time before entering this area. Furthermore, in many cases, fewer gas measuring devices are required in this embodiment than there are workers at the workplace. It is possible for at least one gas measuring device to be fixed in place at a workplace and for at least one further gas measuring device to be worn by a worker at this workplace.

[0017] Preferably, the or each gas measuring device is designed to measure the or each target gas concentration and compare it with the concentration limit throughout the entire period in which the workplace is monitored. It is possible for the monitoring system to comprise at least two gas measuring devices, wherein in one application the two gas measuring devices measure target gas concentrations at the same workplace, in particular of two different target gases, and in another application the target gas concentrations at two different workplaces.

[0018] The or each camera and the or each gas measuring device of a monitoring unit are or can be connected permanently or at least temporarily to the workstation computer of this monitoring unit during an operation, either by cable and / or wirelessly, in particular via radio waves. Preferably, the wired connection can be disconnected again. Thanks to this wired or wireless data connection, the or each camera and the or each gas measuring device can each transmit a signal to the workstation computer. In particular, the or each gas measuring device can transmit an alarm and, optionally, a measured target gas concentration to the workstation computer.

[0019] It is possible to establish a data connection to the workstation computer either via cable or wirelessly. If the camera or gas detector is connected to the workstation computer via cable, the cable is used to transmit the signal; otherwise, the signal is transmitted wirelessly, particularly via radio waves. Optionally, the workstation computer can initiate data transmission in the opposite direction, transmitting a message to at least one connected device in the monitoring unit.

[0020] The monitoring system according to the invention further comprises a communications unit (router) and a first control center. The first control center is spatially remote from the communications unit and the or each monitoring unit and is located outside the or each monitored workstation. In one implementation, the communications unit is located outside the or each workstation, and in another implementation, it is located at or in the or a monitored workstation. The design in which the communications unit is arranged outside the workstation often eliminates the need for the communications unit to meet high requirements for explosion protection and / or resistance to harmful gases. The feature of a separate communications unit thus makes it easier to comply with safety requirements.

[0021] A data connection is established or can be established, at least temporarily, between the or each workstation computer and the communications unit. It is possible for at least two workstation computers to be connected to the same communications unit. The or each data connection uses a cable and / or wireless data transmission, in particular via radio waves. Preferably, a connection established via cable can be terminated again. In one embodiment, this data connection is established either via a cable or wirelessly via radio waves. If a cable connection is established, this is used for data transmission; otherwise, data is transmitted via radio waves.

[0022] The or each workstation computer is capable of transmitting signals from the or each connected camera, from the or each connected gas detector, and optionally from the or each other connected device to the communications unit via this data connection. In particular, the workstation computer is capable of transmitting an alarm from a connected gas detector to the communications unit. Conversely, the workstation computer is preferably capable of transmitting a message to at least one connected device of the monitoring unit. This message concerns, for example, the setting of a sensor at the workstation.

[0023] The first control center comprises a central output computer. A data connection is established, or can be established, at least temporarily between the communication unit and the central output computer. This data connection is or comprises a wireless data connection, in particular a data connection via radio waves. In one embodiment, this data connection is established using a public mobile radio network. Via this data connection, signals can be transmitted from the or each workstation computer via the communication unit to the central output computer. Conversely, a message can preferably be transmitted from the central output computer to the or a workstation computer via the communication unit.

[0024] Both the workstation computer and the communications unit are capable of transmitting data, albeit over different distances. The workstation computer of the monitoring unit for a workstation receives the data from the sensors in or at that workstation, in particular from the gas detector and the camera, and forwards the data received from the sensors to the communications unit. Optionally, the workstation computer receives a message from the communications unit and forwards it to at least one connected sensor. In many cases, the workstation computer can be connected to at least one sensor via a cable; otherwise, or additionally, it can be connected via a wireless data connection in a local network.The data connection between the workstation computer and the communication unit also only needs to bridge a relatively short distance and can be implemented with a cable and / or in a local network.

[0025] The communication unit, on the other hand, receives data from the or each connected workstation and forwards it to the central output computer, wirelessly over at least part of the transmission path, i.e., in a wide area network. Preferably, the distance between the communication unit and the central output computer is at least twice as great, particularly preferably at least ten times as great, as the distance between the communication unit and the or each workstation computer.

[0026] The first control center further comprises at least one output unit. The or at least one output unit preferably comprises at least one screen. Optionally, an output unit comprises a voice output unit. The central output computer is capable of controlling the or each output unit. The controlled output unit is capable of outputting a signal transmitted from the monitoring unit to the central output computer in at least one form perceivable by a human, in particular the image signal from a camera and any alarm from a gas measuring device, and optionally a voice signal. The output unit is capable of outputting the signal in particular visually and / or acoustically and / or haptically (through vibrations). Preferably, the image signal is output visually and the alarm is output at least acoustically and / or haptically, and the voice signal is output acoustically.

[0027] The controlled output unit outputs a display for each monitored workstation. The display for a workstation shows, on the one hand, each alarm from the gas measuring device(s) at this workstation in at least one form that can be perceived by a person, preferably visually. On the other hand, the display shows the respective image signal from the camera(s) at this workstation at any time during monitoring. The preferred embodiment of visually outputting the alarm obviates the need to acoustically inform the operator in the control center about an alarm. Such an acoustic output can be overlooked, particularly if the operator is currently exchanging voice messages with a worker at a workstation. It is also possible to output an alarm in the first control center both visually and acoustically.It is also possible for an alarm to be issued visually in the first control center and acoustically in a further control center. The invention reduces the risk of a worker performing work at a monitored workplace being injured at that workplace without anyone else noticing. In particular, thanks to the gas detector, the monitoring unit can detect whether a target gas has escaped in or at the workplace at a concentration above the concentration limit or is present for some other reason, and then generate an alarm. Because an image signal generated by a camera at the monitored workplace is transmitted to the first control center, an operator in the first control center is able to visually monitor the workplace remotely.In particular, the operator can determine how many and which people are currently in or near the monitored workplace, whether a worker has suffered an accident or fainting spell, and whether or not each worker is wearing the required protective equipment. It is possible, but thanks to the output of the image signal, for an image analysis unit to automatically search for undesirable events in a camera's image signal.

[0028] Because the primary control center is physically removed from the monitored workstation, harmful gases, contamination, and other mechanical or chemical stresses, as well as noise, cannot have a detrimental effect on either the operator or the equipment in the primary control center. Spatial restrictions that often apply to a monitored workstation do not affect the primary control center.

[0029] The invention can be combined with the use of a security guard, i.e., a person who monitors the workstation on-site. However, the invention eliminates the need for such a security guard at the workstation. Instead, an operator can remotely monitor one workstation, optionally at least two workstations simultaneously, from the first control center.

[0030] According to the invention, a signal from a sensor of a monitoring unit is not transmitted directly to the central output computer, but rather to the workstation computer, from there to the communications unit, and from there to the central output computer. A message is transmitted in the same way in the opposite direction. This feature has the following advantages in particular:

[0031] The workstation computer can be located in or near the monitored workstation and, in one embodiment, can supply at least one sensor at the workstation with electrical power. In some cases, a sensor can be connected to the workstation computer via a cable. The workstation computer can process signals locally and optionally perform further calculations. Thanks to the workstation computer, it is not necessary to transmit measured values ​​from a sensor at the workstation to the central output computer, have the central output computer evaluate them, and optionally transmit an evaluation result back to the workstation. The embodiment with the workstation computer therefore saves data traffic compared to a embodiment in which measured values ​​are transmitted directly from the sensors at the workstation to the central output computer, and reduces the risk of delays in data transmission.

[0032] The communications unit eliminates the need to provide a device in or at a monitored workstation that can transmit data to the first control center and bridge the distance between the workstation and the first control center. It is sufficient for the workstation computer to transmit the signals from the sensors to the communications unit. The communications unit can be installed in or at a monitored workstation or near a workstation. Because only a relatively short distance needs to be bridged between the workstation computer and the communications unit, a local data network can be set up and used in many cases. The communications unit forwards signals that it has received from at least one workstation computer and does not necessarily need to perform further calculations.Thanks to the workstation computer, the communication unit also does not need to be directly connected to a sensor at the workstation. It is possible to connect the same communication unit to multiple workstation computers for different workstations. According to the invention, the data connection between the communication unit and the central workstation computer is established using a data connection, wherein this data connection comprises a wireless data connection or is configured as a wireless data connection. This feature makes it easier in many cases to position the central output computer in a desired position relative to the monitoring unit, even at a great distance from or even close to a monitored workstation.The positioning of the central output computer is not limited by the maximum possible length of a cable or by the availability of a stationary power supply network near the monitored workstation.

[0033] According to the invention, the central output computer is capable of controlling the or each output unit, and the controlled output unit generates a display for the or each monitored workstation. The display for the workstation shows the image signal of the or at least one, preferably every, camera of this workstation, as well as each alarm of the or each gas measuring device in at least one form perceivable by a human, particularly visually, acoustically, and / or haptically.

[0034] According to the invention, a display is output for each monitored workstation. This display shows the respective image signal from the camera or cameras at this workstation at any time during monitoring. An operator in the control center can therefore monitor the workstation remotely at any time. In many cases, this design offers greater security than a design in which an image signal is only displayed when a sensor or the monitoring unit at the workstation has generated an alarm. The operator in the control center can in many cases detect a potentially dangerous situation by evaluating the image signal, even if this dangerous situation has not or not yet led to an alarm.It is possible, but thanks to the invention, not necessary, for an image analysis unit to automatically evaluate the image signals from the cameras at the workstations and determine whether a dangerous situation has occurred. Such an image analysis unit may fail to detect a dangerous situation in some cases. Furthermore, such an image analysis unit could produce numerous false alarms.

[0035] In one embodiment, the monitoring system is designed to simultaneously monitor at least two workstations. For each monitored workstation, it comprises a monitoring unit with at least one camera, at least one gas detector, and a workstation computer. The communication unit of the monitoring system is connected to each workstation computer via a data connection. The communication unit is preferably located outside each monitored workstation.

[0036] In a preferred embodiment, the wireless data connection between the communication unit and the central output computer—or the wirelessly implemented part of the transmission path—is implemented using a public mobile radio network. This embodiment eliminates the need to lay a cable or set up a radio link specifically for monitoring the workstation. Instead, a generally already existing infrastructure, namely an existing public mobile radio network, is used for monitoring. The use of a public mobile radio network therefore saves the time required to set up the system and method according to the invention for monitoring the workstation and to dismantle them later if necessary. Furthermore, the public mobile radio network can often bridge a large distance between the communication unit and the central output computer.The first central station can therefore ideally be set up anywhere on earth where there is a connection to a public mobile network.

[0037] In one embodiment, this public mobile network is implemented using at least one central computer. This central computer can be located remotely from the first central station, ideally also at any location on earth with a connection to a public mobile network. Thanks to the public mobile network, the central computer maintains a permanent or at least temporary data connection with the communication unit and a permanent or at least temporary data connection with the central output computer.

[0038] In one embodiment, a monitoring system area for the monitoring system according to the invention is provided and used on this central computer. In one implementation, this monitoring system area is provided and used permanently for the monitoring system according to the invention; in another implementation, it is used only for a specific period of time during which the work at the or each monitored workstation is carried out and completed. It is possible for the monitoring system to be used for monitoring at least one first workstation in a first period of time and for monitoring at least one second workstation in a subsequent second period of time.It is also possible for a monitoring system area to be used on a first central computer during the first period, and a monitoring system area to be used on a second central computer during the second period. The two central computers can be different from each other and located at different locations. This configuration allows, for example, the same workstation to be monitored around the clock without requiring an operator to work at night.

[0039] At least one program is installed in this monitoring system area, including at least one processing program, for example, a web server implemented as software. When executed on the central computer, this processing program generates a dataset that can be presented in at least one form perceivable by a human, in particular visually and / or acoustically. To generate this dataset, the processing program uses the signals received from the or each monitoring unit. This dataset is hereinafter referred to as "processing." This processing is transmitted to the central output computer, for example, in response to a request from the central output computer. Preferably, this processing is continuously updated and transmitted.The processing includes a visually displayable or otherwise outputtable processing of each alarm from the or each gas detector, as well as a visual representation of the respective image signal from each camera. Optionally, the processing includes representations of additional signals from at least one device installed at a monitored workstation and connected to the workstation computer.

[0040] According to the embodiment just described, the central output computer generates the control for the output unit using the processing generated by the central computer and an output program installed on the central output computer, for example, a web browser. The display output by the controlled output unit shows the displayable processing generated by the processing program in at least one human-perceivable form.

[0041] Preferably, a unique internet address is assigned to the monitoring system area used on the central computer. Using the unique internet address, the output program can query data, and thus also the processing, from the monitoring system area. It is also possible for the communication unit to be assigned a unique internet address, allowing the output program to query data from the communication unit. These two configurations can be combined.

[0042] Functionally, the monitoring system area on the central computer with the or each processing program thus belongs to the first control center, even if it is installed on the central computer and not in the first control center. When specifying below what the central output computer and / or the first control center can be configured for and / or which steps they can perform, this includes the possibility that some of these configurations and steps are implemented and / or executed by the or a program on the central computer.

[0043] The design in which the processing program that generates the processing is installed on the central computer makes it possible to use a central output computer that requires less computing power and / or storage capacity than if the output computer itself were to generate the display for the output unit in the first central station and directly use the alarms and signals from the or each workstation computer for this purpose. This, in turn, makes it possible to design the central output computer as a relatively small and lightweight device, in particular as a portable computer, in particular a laptop, tablet, or smartphone. The central computer, on the other hand, can be equipped with the necessary computing power relatively easily. It does not require an output unit capable of outputting a signal from a device at a monitored workstation, nor does it require an input unit for user inputs.

[0044] Optionally, the monitoring system comprises at least one second control center in addition to the first control center. The second control center, like the first control center, is spatially separated from the communications unit and from the or each monitored workstation. Furthermore, the second control center is spatially separated from the first control center. Just like the first control center, the second control center also comprises a central output computer and an output unit. The monitoring system area of ​​the central computer is permanently or at least temporarily in data communication with the second central output computer, i.e., with the central output computer of the second control center. The second central output computer can control the output unit of the second control center and cause the second output unit to output a display. A second output program is preferably installed on the second central output computer.The display on the second output unit is generated in the same way as the display on the output unit of the first central unit, using the format generated by the formatting program on the central computer. Thus, the same format from the same formatting program is displayed twice, namely on different output units.

[0045] This configuration allows the monitoring of the workstation(s) either in the first control center or in the second control center. Each control center has a permanent or at least temporary data connection to the same monitoring system area of ​​the central computer and uses the same processing generated by the central computer's processing program. Both control centers therefore use the same display and thus the same signals from the sensors at the monitored workstations, simultaneously, except for potentially different transmission times. It is not necessary for an alarm or other signal to be transmitted from one workstation computer to the first control center and from the first control center to the second control center. Rather, the two control centers are arranged in parallel.

[0046] The design with at least two control centers creates redundancy because the workstation or each workstation is or can be monitored simultaneously by two operators in two control centers. This reduces the risk of a dangerous situation being overlooked. On the other hand, this design increases safety. It is possible that an operator in one control center can no longer monitor the workstation or each workstation, for example due to a technical defect or fainting spell, or due to human error. In this case, the other control center is still available for monitoring. The physical distance between the two control centers reduces the risk of both control centers failing simultaneously due to a technical problem or external influences.

[0047] In some cases, using two control centers makes it easier to monitor one or more workstations around the clock without requiring an operator at one control center to work at night. For this application, the two control centers are located in different time zones. Each control center is used during a period that falls within a predefined time range of the day in that time zone, for example, between 6:00 a.m. and 6:00 p.m. Of course, it is also possible to monitor the same workstations from three control centers.

[0048] It is possible for the second control center to be implemented using a portable computer, particularly a tablet or smartphone. An operator can carry this device with them and perform monitoring from any location, especially near a monitored workstation.

[0049] It is possible for an operator at the first control center to regularly request user input. If no user input is registered at the first control center within a specified period, the system automatically switches to the second control center, optionally after a request to an operator at the first control center to now provide user input. This configuration further increases the reliability of remote monitoring.

[0050] The advantages of the first control center described above as well as the advantageous embodiments of the first control center described below can also be applied to the second control center or to any second control center.

[0051] According to the invention, at least one image signal from a camera in or at a workstation is transmitted to the central output computer via the workstation computer for this workstation, the communication unit, and the wireless data connection. This transmission is preferably carried out via a public mobile radio network, optionally instead via a radio link. This transmission requires bandwidth. In a public mobile radio network used according to the preferred embodiment, other communication units generally also consume bandwidth, often at the same time, so that the monitoring system according to the invention at least temporarily competes with other communication units for the currently available bandwidth. The transmission of an image signal generally requires a greater bandwidth than the transmission of an alarm or other signal from a workstation.Therefore, the situation may arise that the currently available bandwidth is not sufficient to transmit the or each image signal with the maximum possible image quality to the central output computer.

[0052] The following describes a design that solves this problem. According to the design involving the mobile network and the central computer, signals from various devices in the monitoring unit are transmitted to the central computer and from there, as part of the processing, to the central output computer. These signals include at least one image signal generated by the camera(s) of the monitoring unit. Typically, the transmission of the image signal requires a significantly greater bandwidth than the transmission of the other signals from the devices in the monitoring unit. This is because the other signals generally do not include image data or even video data.

[0053] According to the embodiment, the or at least one, preferably every camera of the surveillance system has at least one externally modifiable and bandwidth-relevant parameter. It is possible for at least one camera to have multiple bandwidth-relevant parameters. The current value of a bandwidth-relevant parameter influences the bandwidth required to transmit an image signal from this camera to a spatially distant receiver. By controlling the camera externally, the currently used value of a bandwidth-relevant parameter can be changed. This change can be carried out during ongoing operation. During ongoing operation, the camera is used to monitor a workstation and in doing so generates an image signal. The surveillance system can automatically control the or at least one, preferably every camera that has at least one externally modifiable and bandwidth-relevant parameter.The goal of this control is to change the respective value of at least one bandwidth-relevant parameter. The change resulting from the control causes the bandwidth required to transmit the image signal from this camera to be changed. In particular, the required bandwidth is reduced, at least temporarily. It is also possible to temporarily increase the bandwidth to obtain an image signal with higher image quality.

[0054] In one embodiment, an operator in the control center causes the value of the or at least one bandwidth-relevant parameter of a previously selected camera to be changed through a corresponding user input, thereby reducing or increasing the required bandwidth. Preferably, the operator selects at least one camera, and the surveillance system automatically changes the value of the or each bandwidth-relevant parameter of the selected camera. Optionally, the operator also specifies whether the image quality of the image signal from the selected camera should be improved or whether, alternatively, a deterioration in image quality is acceptable. For example, the operator selects one camera and thereby specifies that the image signal from this camera currently only needs to have a lower image quality than other image signals.

[0055] In a preferred embodiment, however, a component of the surveillance system is capable of automatically determining a measure of the bandwidth currently available in the public mobile radio network or in a radio link used to transmit signals from the communications unit to the central output computer. In particular, the component of the surveillance system is capable of automatically detecting an indication of insufficient bandwidth. Typically, the signals are transmitted in the form of data packets. In this case, the component of the surveillance system is capable of preferentially detecting the event that data packets are lost ("packet loss", "packet drop"). The loss of data packets is an indication of insufficient bandwidth. The surveillance system is capable of automatically controlling at least one camera with the aim of changing the value of the or at least one bandwidth-relevant parameter.It is possible, but thanks to this design, it is not necessary for the camera itself to automatically detect the bandwidth measurement and change the bandwidth.

[0056] These two configurations can be combined. This combination allows the operator to select a camera, while the surveillance system can automatically control at least one camera with the aim of changing, in particular reducing, the required bandwidth.

[0057] According to the configuration just described, the component of the monitoring system is capable of automatically determining a measure of the bandwidth currently available in the public mobile network or in a radio link used to transmit signals from the communication unit to the central output computer. Different implementations are possible, depending on which component of the monitoring system is capable of determining this measure of bandwidth.

[0058] In one implementation, the central output computer can automatically determine the available bandwidth. In another implementation, the communications unit does this. In a preferred implementation, however, the workstation or at least one, preferably each, of a monitoring unit can automatically determine the currently available bandwidth. The determined bandwidth refers to the transmission path from the workstation via the communications unit to the central output computer or to an optional central computer. The determined bandwidth can be different for different workstations.

[0059] The design in which the workstation computer or a workstation computer determines the bandwidth measure has the following particular advantage: The most bandwidth is required to transmit an image signal from a camera to the central output computer. The camera's image signal is transmitted via a transmission path. This transmission path comprises a first part between the camera and the workstation computer and a second part between the workstation computer and the central output computer. The first part can be implemented using a cable and / or a local wireless network and usually provides sufficient bandwidth. Insufficient bandwidth usually only affects the second part of the transmission path, i.e. the transmission from the communications unit to the central output computer.The workstation computer is generally better able to determine the bandwidth in this second part of the transmission path than the central output computer or an optional central computer. Furthermore, this configuration eliminates the need to transmit a message with the available bandwidth to the workstation computer. Preferably, the workstation computer assigns a different value to the bandwidth-relevant parameter of the connected camera.

[0060] In one implementation, a data connection between the communications unit and the central output computer is established using a public mobile radio network, and this public mobile radio network is implemented using at least one central computer. In one embodiment, the monitoring system according to the invention utilizes a monitoring system area of ​​the central computer. The processing program described above can be installed on this central computer and belong to the monitoring system area. It is possible for the central output computer or the communications unit, or even the workstation computer or a workstation computer, to query the available bandwidth from the central computer.

[0061] The image quality with which image signals are displayed on an output unit in a control center generally depends essentially on the bandwidth currently available in the public mobile network or in a microwave link in use. The bandwidth available in the data connection between the workstation computer and the communications unit or in the data connection between the camera and the workstation computer of a surveillance unit, on the other hand, generally has little influence on the image quality. This is because other communications units do not generally compete for the bandwidth available for data transmission from the camera to the communications unit. Therefore, the workstation computer is usually able to detect insufficient bandwidth, even if the workstation computer is not directly connected to the public mobile network.

[0062] Preferably, the workstation computer is capable of controlling the camera or cameras connected to it with the aim of changing the value of the bandwidth-relevant parameter and thereby reducing or increasing the required bandwidth. Particularly preferably, the workstation computer is capable of causing the respective parameter value of the camera or cameras connected to it to be changed in response to the determination of the currently available bandwidth. The last-described implementation, in which the workstation computer itself determines the measure of the currently available bandwidth, eliminates the need to transmit a message regarding the available bandwidth to this workstation computer.Rather, each workstation reduces or increases the required bandwidth as needed, independently of the other workstation, the communications unit, the central output computer, and the optional central computer. In many cases, this ensures that the required bandwidth is reduced quickly when needed. In many cases, it is ensured that, despite lower bandwidth, every image signal is still transmitted to the central workstation, albeit possibly with lower image quality. This ensures that, even with lower bandwidth, the workstation is continuously monitored.

[0063] The design, in which the workstation computer controls the or each camera with the aim of changing the value of the bandwidth-relevant parameter, eliminates the need for the central output computer to directly control the camera. This saves data traffic and reduces the risk of high latency. On the other hand, this design eliminates the need for the camera itself to have a control unit that can change the parameter value depending on the available bandwidth. This allows for a simpler camera design. In many cases, it makes it easier for the camera to meet specified safety requirements, for example, those relating to explosion protection.

[0064] According to the embodiment just described, a component of the surveillance system, in particular the workstation computer or a workstation computer, is capable of automatically changing at least one value of a bandwidth-relevant parameter of a camera, thereby reducing or increasing the bandwidth required to transmit an image signal from this camera to a remote receiver. Preferably, the workstation computer is capable of controlling the camera and thereby changing the parameter value.

[0065] The implementation described below leads to the following result: The more people are currently at a workstation, the more bandwidth is available to transmit an image signal from a camera located in or at that workstation, and the higher the image quality of the image signal. This effect is advantageous for the following reason: The more people are at or in the workplace, the greater the risk that someone will be injured due to an accident or other incident, or the risk that someone is not wearing the prescribed personal protective equipment. Therefore, it is desirable that the image quality with which images from that workstation are displayed on the output unit is higher the more people are there. If there is no one there at the time, the image quality may be lower, and less bandwidth is required.Nevertheless, an image signal is still transmitted in this case.

[0066] Different implementations are possible for determining how many people are currently in or at a workstation. It is possible for the operator in the control center to count how many people are shown in an image signal, with this image signal originating from a camera at that workstation. It is also possible for an image evaluation unit to evaluate the or each image signal from the or a camera to determine the number of people present. The implementation described below avoids the need for an operator or an image evaluation unit to count the people. This implementation can be combined with counting by evaluating a displayed image signal.

[0067] According to this implementation, the monitoring unit includes at least one access control unit. Preferably, a person logs in to this access control unit when entering the workstation and logs out again when leaving. Each login and each logout triggers a signal from the access control unit.

[0068] Using signals from this access control unit, the monitoring system can determine how many people are currently in or at this workstation. In one implementation, the workstation computer determines how many people are at this workstation. This implementation eliminates the need to transmit signals from the access control unit to the first control center. In another implementation, the central output computer or an optional central computer determines the number of people. This implementation eliminates the need to equip the workstation computer with the necessary computing power. It is also possible for the access control unit itself to count how many people are currently in or at the monitored workstation and transmit a corresponding signal to the workstation computer or to the control center.In all implementation forms, the determined number of persons currently in or at the workplace, as well as an identifier for each person, are preferably output on the or an output unit of the control center in a form that can be perceived by a person, in particular visually.

[0069] To determine the number of people at the monitored workstation, in one implementation the central output computer uses the signals from the access control unit, whereby these signals are transmitted to the central output computer via the workstation computer and the communications unit. In a preferred embodiment, the above-mentioned optional central computer for the mobile network automatically counts how many people are currently in or at the workstation and inserts the count result into the processing described above. The central computer uses signals from the access control unit for the counting. The central workstation computer queries the central computer for the determined number of people, in particular as part of the requested processing.

[0070] In one implementation, the workstation computer determines how many people are currently at the monitored workstation based on signals from the access control unit, and optionally, which people these are. In another implementation, the workstation computer simply detects the event that a person has logged in or logged out and transmits a corresponding message to the central output computer. This message preferably includes a detected unique identifier of the person who logged in or logged out. The central output computer, or the central computer, or the workstation computer counts how many people are currently in or at the monitored workstation according to the signals from the access control unit.

[0071] A configuration has already been described above in which the surveillance system can control the camera or at least one camera at a monitored workstation with the aim of changing the value of a bandwidth-relevant parameter. Preferably, the workstation computer itself can control the camera. Suitable control of the camera reduces data traffic between the first control center and the monitoring unit for the workstation. This configuration can be combined with the configuration in which the number of people currently in or at the monitored workstation is determined. In many cases, this combination results in less bandwidth being required to transmit an image signal from the workstation without significantly reducing the reliability of the monitoring.

[0072] This combination enables the surveillance system to control the camera depending on the detected number of people. Preferably, the workstation computer of the monitoring unit for the workstation carries out the control. The control changes the value of the bandwidth-relevant parameter as needed. One aim of the control is, on the one hand, that the lower the detected number of people, the lower the required bandwidth. This is because, in many cases, the image signal may show fewer details for a small number of people than for a large number. On the other hand, the controlled camera continuously transmits an image signal during surveillance, even if the access control unit has not detected a person. This takes into account, in particular, the possibility that a person may be in or at the workstation without having been registered by the access control unit.In addition, in many cases it is possible to warn a person before entering the workplace, for example if there is a dangerously high concentration of a target gas or a mechanical hazard, especially a visually perceptible one.

[0073] Using a signal from the access control unit for a workstation, a component of the monitoring system, for example, the central workstation computer, can determine that no one is currently in or at the workstation. However, this result can be erroneous, particularly if a person has entered the workstation without checking in with the access control unit, or if the access control unit incorrectly fails to register a person's check-in, or if a signal from the access control unit is not transmitted to the workstation computer. Therefore, in this case, an image signal is preferably transmitted from the workstation to the central output computer, preferably with a relatively low image quality.

[0074] According to the configuration just described, at least one camera can be controlled with the aim of assigning a different value to a bandwidth-relevant parameter of the camera. As a result, the bandwidth required to transmit the image signal from this camera to the central output computer is changed.

[0075] As a rule, the more bandwidth used to transmit the image signal, the better the image quality. To achieve the highest possible image quality, in a preferred embodiment the image quality is increased on a trial basis. This is done by assigning a correspondingly modified value to at least one bandwidth-relevant parameter. The change is initiated by an external control while the workstation is monitored, preferably by the workstation computer. A check is automatically carried out to determine whether or not the bandwidth is currently sufficient to transmit an image signal for a higher image quality after the assignment. This check preferably checks whether any data packets are lost.If the bandwidth is insufficient, a different value is assigned to the same or another bandwidth-relevant parameter of the camera or another camera at the same workstation with the aim of reducing the required bandwidth again. In many cases, this configuration results in the available bandwidth being utilized effectively and a high-quality image signal being transmitted, even if the total available bandwidth varies over time. This step can be repeated regularly.

[0076] As already explained, in one embodiment, a component of the surveillance system, preferably the workstation computer or a workstation computer, can control the camera or at least one camera, preferably each camera, with the aim of assigning a different value to at least one bandwidth-relevant parameter of the camera and then using this value. The parameter value influences the bandwidth required to transmit the image signal from this camera to a remote receiver. As a rule, the greater the bandwidth used, the better the image quality with which the image signal is visually displayed in the control center. A preferred implementation of a camera with several bandwidth-relevant parameters is described below.

[0077] According to this implementation, the camera or at least one camera comprises a photosensor and a signal-processing image processing unit, and preferably a dedicated control unit. The photosensor is capable of generating images based on incident electromagnetic waves, in particular light rays, and storing them at least temporarily in a data memory of the camera. Two bandwidth-relevant parameters relating to the photosensor are

[0078] - the resolution (number of pixels), which is the number of pixels in an image created by the photosensor, and

[0079] - the frame rate (“frames per second”), which is the number of images per unit of time with which the photosensor creates images.

[0080] The camera can be controlled externally with the aim of changing the resolution and / or the frame rate.

[0081] The image processing unit generates the image signal, which is transmitted from this camera to the central output computer and output on the output unit in a manner perceivable by a human. To generate the image signal, the image processing unit uses images from the photosensor and applies an algorithm to these images. Another bandwidth-relevant parameter is a parameter of the algorithm that the image processing unit applies. The algorithm preferably causes the images from the photosensor to be compressed so that the image signal requires less bandwidth than if the images from the photosensor were transmitted without compression processing. The parameter for the image processing unit influences the algorithm with which the image processing unit processes images from the photosensor to generate the image signal and is therefore another bandwidth-relevant parameter.Preferably, the parameter influences the compression rate achieved by the image processing unit. A different value can be assigned to the parameter for the algorithm through external control. It is possible for multiple bandwidth-relevant parameters to influence this algorithm, and for each of these parameters to be assigned a different value independently of one another through external control.

[0082] Overall, in many cases, a camera has at least three bandwidth-relevant parameters, i.e. at least three parameters whose values ​​influence the bandwidth required to transmit an image signal from this camera to the central output computer.

[0083] At least one of the bandwidth-relevant parameters mentioned can be changed by external control, preferably at least two parameters. Particularly preferred is at least two or even all parameters that can be changed independently of one another. A camera often has the bandwidth-relevant parameters just mentioned. It is also possible that only one of these parameters can be changed by external control, while all others remain constant during use.

[0084] According to the invention, the controlled output unit outputs a display for each monitored workstation. This display for a workstation shows each alarm from the gas measuring device(s) at this workstation during monitoring, as well as the respective image signal from at least one camera, preferably every camera, at this workstation at any time during monitoring.

[0085] In one embodiment, the output unit comprises a screen. On this screen, a representation is output for the or each monitored workstation, which functions as the or a representation within the meaning of the patent claims. Thus, if n workstations are monitored simultaneously, n representations are output on this screen simultaneously. An operator at the control center can thus monitor n workstations simultaneously while viewing the screen.

[0086] For the display output, each monitored workstation is assigned an area on the screen. If there are n monitored workstations, this means n different screen areas on the same screen. The display for the workstation is displayed in this assigned screen area. The display displayed in the screen area for a monitored workstation shows, on the one hand, the respective image signal from the or each camera at this workstation. On the other hand, the display in the screen area includes visually perceptible information about whether the or at least one gas measuring device or the workstation computer at this workstation is currently generating an alarm or not. It is possible to also output such an alarm acoustically or haptically (through vibrations).In one embodiment, the display for a monitored workplace additionally includes an identification of this workplace and / or the number of persons currently in or at the workplace.

[0087] According to this design, both the image signal and the information as to whether or not an alarm is present at the workstation are visually output in the same screen area. It is possible, but not necessary, to also output a measured target gas concentration in this screen area. This design feature results in a particularly ergonomic display. An operator in the first control center can, at a glance, assign an alarm to an image signal, or vice versa, an image signal to an alarm. The operator can see at a glance at which workstations an alarm concerning a harmful target gas concentration is currently being generated and can simultaneously see at least one image signal from this workstation without having to switch their attention back and forth between two different screens or screen areas.The operator does not need to evaluate a textual description of a workstation or record an acoustic alarm to assign an alarm to an image signal, or vice versa. In many cases, this design allows for reliable monitoring of multiple workstations simultaneously from the same primary control center.

[0088] In many cases, it is not necessary to provide separate information indicating which workstation an alarm refers to. Furthermore, thanks to this design, the user does not need to switch between one visual and another display mode, in particular between a visual display of an image signal and an acoustic alarm. This feature is particularly advantageous and leads to particularly ergonomic monitoring when an operator in the control center monitors several workstations simultaneously.

[0089] It is possible for the output unit to include at least one additional screen. Preferably, more detailed information about a workstation is displayed on this additional screen if the gas measuring device(s) or the workstation computer at this workstation has generated an alarm, or if the operator has previously selected this workstation. In one implementation, the more detailed information includes the or at least one, preferably every, measured target gas concentration at this workstation.

[0090] The monitoring system according to the invention can be used to permanently monitor at least one workstation remotely. According to another application, the monitoring system according to the invention is used to remotely monitor at least one workstation only for a predetermined period of time. During this period, at least one task is carried out and completed in or at the monitored workstation. Preferably, a technician assembles the monitoring system or at least the monitoring unit up to the start of this period, enables monitoring of the workstation from the control center during this period, and dismantles the monitoring system or at least the monitoring unit again after the work has been completed. It is possible for the same monitoring system to then be used to monitor at least one other workstation.The same control center at the same location and the same monitoring unit can be used to remotely monitor a first and then a second workstation. Because the monitoring system, or at least one monitoring unit, can be assembled and disassembled, devices of the monitoring system can be reused, in particular devices of the monitoring unit(s) and the communications unit. This application requires transporting the monitoring unit to the vicinity of the workplace to be monitored, moving the workstation computer, the camera(s), the gas detector(s), and optionally at least one other device of the monitoring unit into a desired position relative to the workplace to be monitored, and then establishing the necessary data connections.This is facilitated if the entire transmission unit can be carried by one person, and no vehicle or crane is required for transport. Therefore, the devices of a monitoring unit preferably have a total mass (aggregated mass) of no more than 20 kg, particularly preferably no more than 10 kg. This design allows a person to transport the devices in a suitable container, for example, a backpack, to the workplace, and a technician to assemble the devices there.

[0091] Preferably, the control center devices and the communications unit can also be transported by a single person. Particularly preferably, the combined weight of all control center devices is no more than 50 kg, in particular no more than 20 kg. The weight of the communications unit is preferably less than 5 kg, particularly preferably less than 2 kg. This configuration makes it possible to set up the control center or a control center for use in sufficient proximity to the or at least one monitoring unit and to dismantle it again after use. “Sufficient proximity” means, in particular, that the public mobile radio network or the radio link used is sufficient for transmitting signals to the central output computer. The control center devices can be used sequentially to monitor different workstations.Preferably, the processing program described above, as well as optionally other functions of the central unit, are installed not on the central output computer, but on the central computer for the public mobile network described above. This configuration facilitates the transport of the central unit's devices.

[0092] Preferably, each device of the monitoring unit is designed as an intrinsically safe device, thus meeting explosion protection requirements. In particular, suitable components of each device ensure that the current and electrical voltage, as well as the release of heat energy, are limited at all times during operation and that no sparks escape. The device can therefore also be used in a potentially explosive environment, particularly in an environment in which at least one flammable target gas can escape. Configuring the monitoring unit exclusively with intrinsically safe devices often enables the following procedure: The devices of a monitoring unit are transported individually to the workplace to be monitored, and only at or in the workplace are the devices assembled to form the monitoring unit.Because the devices are intrinsically safe, this procedure is possible even if the workplace is in a potentially explosive atmosphere. In many cases, it is possible, but thanks to the intrinsically safe devices, to assemble the monitoring unit outside the workplace in a non-hazardous environment and then transport the assembled monitoring unit to the workplace as a whole.

[0093] It is often desired that a person in or at the monitored workstation and an operator in the control center or a central unit can exchange voice messages. In a preferred embodiment, the or at least one monitoring unit comprises a voice input unit and a voice output unit, which preferably have a microphone and a loudspeaker and are located in or at the monitored workstation. The control center also comprises a voice input unit and a voice output unit, which preferably have headphones and a microphone. Thanks to the headphones, the operator can hear voice messages without being disturbed or distracted by noises in their environment.A person in or at the monitored workstation can enter a voice message into the voice input unit at the workstation. This voice message is transmitted via the workstation computer, the communications unit, the wireless data connection and the central output computer to the voice output unit in the control center, where it is output acoustically, preferably on the headset. Conversely, an operator in the control center can enter a voice message into the voice input unit in the control center. This voice message is transmitted via the central output computer, the wireless data connection, the communications unit and the workstation computer to the workstation, where it is output acoustically, preferably on the loudspeaker. The use of a loudspeaker at the workstation eliminates the need for a worker to use headphones at the workplace.It is also possible for the voice output unit at a workstation to also include headphones so that a worker can understand the voice message even in a noisy environment.

[0094] According to the invention, the controlled output unit in the central unit is capable of outputting signals from the or each monitored workstation, in at least one form perceivable by a human. The controlled output unit generates a display for each monitored workstation. These signals include an image signal from the or each camera in or at this workstation and an alarm from the or each gas measuring device. Optionally, these signals also include target gas concentrations measured by the gas measuring device and / or voice messages from a person at the workstation and the number of people currently at the workstation. The central output computer is capable of controlling the output unit. In a preferred embodiment, the output unit comprises an overview screen and at least one further screen for a visual output of image signals and optionally of further signals.Each screen can be controlled from the central output computer. The controlled overview screen can visually display the image signals from at least two cameras simultaneously – of course, only if these two cameras generate image signals simultaneously and each have a data connection to the central output computer. The two cameras can be installed in or at the same workstation and belong to one and the same monitoring unit. They can also belong to two different monitoring units for two different monitored workstations. Thanks in particular to the overview screen, the operator can visually monitor multiple workstations simultaneously.

[0095] The central output computer can control the overview screen. The overview screen is controlled in such a way that a section of the overview screen is used for each monitored workstation. The display for this workstation is output in this screen section. Therefore, with n monitored workstations, one display is output in each of n screen sections. In particular, the respective image signal from the or each camera at the workstation is output in this screen section. Preferably, this screen section also outputs in a visually perceptible manner whether the or at least one gas detector at the monitored workstation is currently generating an alarm or not.

[0096] In one implementation, the or each additional screen is connected to the overview screen by means of a hinge, for example, like the two wings of an altarpiece. This design allows two screens to be folded together and then transported.

[0097] The additional screen, or at least one of the other screens, can display information about one workstation at a time. This workstation was previously selected. It is also possible that a gas detector at this workstation is currently generating an alarm. Preferably, the additional screen displays information about this workstation until another workstation is selected or the information display is stopped.

[0098] In one implementation, the operator in the control center has selected this workstation. In another embodiment, the central output computer has received an alarm from the or a gas measuring device or from the workstation computer or from another device in or at this workstation, and based on this alarm, the workstation is automatically selected. The information about the workstation that is output on the additional screen preferably includes the or at least one target gas concentration that the gas measuring device measured and which lies above the specified concentration limit. This target gas concentration therefore triggered the alarm. The alarm and a message with the target gas concentration were therefore transmitted from this workstation to the control center, with the alarm being transmitted with a higher priority than the target gas concentration.The additional screen displays information about this workstation with the alarm. This configuration makes it easier for the operator to determine the cause of an alarm and initiate appropriate measures. Preferably, the information displayed also includes the image signal (or at least one image signal) from a camera at this workstation and / or the number and / or names of the people present at this workstation according to the signals from the access control unit.

[0099] According to the invention, the or each gas measuring device or the workstation computer of the or a monitoring unit is capable of automatically generating an alarm if the or a measured target gas concentration lies above a concentration threshold specified for this target gas. This concentration threshold is preferably stored in a data memory of the gas measuring device or the workstation computer. This alarm is transmitted to the central output computer. In one embodiment, the central output computer, in response to receiving an alarm, is capable of controlling the output unit in such a way that the following occurs: The controlled output unit outputs a list, either visually or in another form perceivable by a human. The output list specifies the workstation to which the alarm relates, i.e. the workstation at or in which the gas measuring device that generated the alarm is located.Furthermore, the list specifies at least one action, preferably every action, that must be taken in response to the alarm at the workstation. This design makes it easier for an operator to quickly initiate the required action or actions when an alarm is generated and reported to the control center. This reduces the risk that a required action will not be taken at all or will be taken too late.

[0100] In one implementation, the list additionally includes an input field for at least one, preferably for each, measure listed in the list. By entering an input into this input field, the operator triggers the outputted measure to be executed in one implementation, without necessarily having to perform any further action. In another implementation, the operator confirms by making the input that he or she has triggered the measure. Preferably, the central output computer generates a message to the operator if the operator has not yet entered a confirmation for a measure listed in the list.

[0101] An embodiment was described above in which the output unit comprises an overview screen and at least one additional screen. Preferably, the just-described list is output on the overview screen or on an additional screen.

[0102] It is possible for the output unit to include two additional screens. This allows two different workstations to be selected simultaneously. This is particularly advantageous if a gas detector or other device has generated an alarm at two different workstations at almost the same time. It is particularly preferred to display a list for each selected workstation on an additional screen.

[0103] A design has already been described above in which a screen area is assigned to each monitored workstation on the overview screen. The display for the workstation is output in this screen area. This display includes the respective image signal from the or each camera at the workstation. Furthermore, the display is output in a first way when a gas measuring device or the workstation computer generates an alarm for this workstation, and in a second way when neither a gas measuring device nor the workstation computer generates an alarm. For example, the output image signal is surrounded by a frame, and the frame shows in a visually perceptible way whether an alarm is generated or not. This frame visually separates the screen area for a workstation from the or any other screen area on the overview screen.

[0104] The design with screen areas makes it easier for the operator to locate workstations with alarms at a glance and to link the image signals to the alarms. This design can be combined with the design described above, in which a list is displayed on another screen, with this list referring to a workstation where an alarm is generated. The combination of these two designs makes it easier for the user to link the list with the image signal. The combination thus results in a particularly ergonomic design for monitoring.

[0105] Preferably, the workstation or at least one workstation, particularly preferably each workstation, comprises its own power supply unit. This configuration avoids the need to connect the workstation to a stationary power supply network. In many applications, this is not possible or undesirable, particularly because a long cable to the monitored workstation would be too dangerous. Furthermore, in some applications, the workstation must meet explosion protection requirements.

[0106] On the one hand, it is usually desired that this dedicated power supply unit supplies the workstation computer with electrical power for as long as required. On the other hand, it is often desired that the power supply unit be relatively small and lightweight, especially so that it can be easily transported to the workstation and / or detachably attached there. This latter constraint limits the electrical energy that the power supply unit can provide. Furthermore, the dedicated power supply unit is often also required to be an intrinsically safe device. The following preferred implementation of a dedicated power supply unit meets these requirements.

[0107] According to this implementation, the power supply unit of the workstation computer comprises an internal power source and at least one external power source. Each power source is capable of supplying the electrical load(s) of the workstation computer with electrical energy, optionally also a connected sensor. Preferably, each power source is rechargeable. Preferably, the workstation computer with the internal power source and the external power source(s) are designed as intrinsically safe devices. The internal power source is arranged in a housing of the workstation computer and is thus protected to a certain degree from external influences. The external power source(s) is detachably connected to the workstation computer or can be detachably connected to it. In many cases, an external power source can thus be replaced during operation, i.e., in or at the monitored workstation, i.e.Replace with a new one. Replacement is especially necessary when the previously used external power source is largely discharged. Often, monitoring of the workstation does not need to be interrupted to replace the external power source. If the workstation computer and any external power source are designed as intrinsically safe devices, the replacement can even be carried out in a potentially explosive environment.

[0108] For as long as possible, the workstation's electrical load(s) and each connected load(s) are supplied with electrical energy from the connected external voltage source(s). "As long as possible" means: as long as the level of the connected external voltage source is greater than or equal to a predetermined first level threshold. The workstation's electrical load(s) are only supplied from the internal voltage source when no external voltage source is connected or when the connected external voltage source(s) has a level below the first level threshold. The internal voltage source thus functions as a type of buffer storage for electrical energy.One reason for preferring an external power source is the following: While an external power source can often be hot-swapped, it is generally not possible to hot-swap or recharge the internal power source, especially if the workstation is used in a potentially explosive environment. This generally applies even if the workstation is designed as an intrinsically safe device. At the very least, however, replacing the internal power source requires more time than connecting it to another external power source.

[0109] Preferably, a signal-processing control unit of the workstation computer switches between a supply from the or an external voltage source and a supply from the internal voltage source. Preferably, the control unit repeatedly checks whether at least one external voltage source with a sufficient charge level is connected and, if so, switches to this external voltage source.

[0110] Preferably, the workstation computer generates a message when the fill level of the or a connected external voltage source has fallen below a predetermined second fill level threshold. The second fill level threshold is greater than or equal to the first fill level threshold. The message is output in a form perceivable by a human, for example on an output element of the workstation computer itself or on the output unit of the control center. If the second fill level threshold is greater than the first fill level threshold, more time is available to replace the external voltage source without having to use the internal voltage source. This is because the low fill level message is output before the fill level has fallen below the first fill level threshold.

[0111] In one embodiment, the workstation computer can be connected to at least two external voltage sources simultaneously. This allows the workstation computer to be used for longer without an external voltage source having to be replaced. Preferably, the or each electrical load is supplied from a first external voltage source until the fill level of the first external voltage source has fallen below the first fill level threshold. Preferably, the second external voltage source is not used as long as the fill level of the first external voltage source is high enough. The electrical loads are then supplied from the or a second external voltage source. The period of time that elapses until the fill level of the second external voltage source has also fallen below the first fill level threshold is available for replacing the first external voltage source.

[0112] The communication unit preferably also comprises its own power supply unit. This can be constructed in the same way as the one just described with reference to the workstation computer. In one embodiment, the or each camera and / or the or each gas measuring device of a monitoring unit each comprises its own power supply unit. This can be configured as just described with reference to the workstation computer. It is also possible for at least one gas measuring device and / or at least one camera and / or an optional additional device of the monitoring unit to be supplied with electrical energy by the workstation computer. The or at least one camera is therefore an electrical consumer that is at least temporarily supplied with electrical energy by the workstation computer. These two implementations can be combined.This combination allows the workstation computer to supply at least one additional device in the monitoring unit with electrical power via a cable, provided this additional device is located close enough to the workstation computer, but the additional device can also be positioned at a more distant location. It is also possible for a device at the workstation to be powered either by the workstation computer or by its own power supply unit.

[0113] It is also possible that the gas measuring device or at least one of them is supplied with electrical energy from the workstation computer.

[0114] According to the invention, the monitoring system comprises a communications unit and a monitoring unit for each monitored workstation. In a preferred embodiment, n workstations are monitored simultaneously, where n >= 2. The monitoring system comprises at least n monitoring units, each with a workstation computer, at least one camera, and at least one gas measuring device. Preferably, the same communications unit is connected to each of these n workstation computers simultaneously. This embodiment saves on devices compared to an embodiment in which a separate communications unit is used for each monitored workstation. The embodiment also saves on data connections compared to an embodiment in which each workstation computer or even each sensor is connected directly to the central output computer.It is sufficient to establish an at least partially wireless data connection between the communication unit and the central output computer. According to a further development of this embodiment, at least two workstation computers and the communication unit are connected in series ("daisy chain") as follows: A first data connection is established or can be established, at least temporarily, between the workstation computer of the first monitoring unit and the communication unit. A second data connection is established or can be established, at least temporarily, between the workstation computer of the second monitoring unit and the workstation computer of the first monitoring unit.Signals from the remaining devices in the second monitoring unit are transmitted to the communications unit as follows: from the device at the workstation to the workstation computer of the second monitoring unit, from there via the second data connection to the workstation computer of the first monitoring unit, and from there via the first data connection to the communications unit. Optionally, all n workstation computers for the n simultaneously monitored workstations and the communications unit are connected in series. Signals from a sensor are thus forwarded through this series to the communications unit and from there to the central output computer. In many cases, the series connection requires fewer data connections than other types of circuits, for example, fewer than a star connection.

[0115] In order to be able to monitor a workstation remotely, it is necessary that a data connection is established between the devices of the assigned monitoring unit and the central output computer. The undesirable event that this data connection is interrupted during monitoring must be able to be detected quickly. In one embodiment, the central output computer generates a request message for each monitored workstation. This request message is preferably generated repeatedly, for example at fixed time intervals. The central output computer triggers the step of transmitting the request message for a workstation to the workstation computer of this workstation. In response to receiving the request message, the workstation computer generates a response message. This response message is transmitted to the central output computer.The central output computer checks whether a response message arrives from a workstation within a specified time period after the request message has been sent to that workstation. If this is not the case, the central output computer generates an alarm and displays this alarm in at least one human-perceivable form.

[0116] Preferably, the reverse sequence is performed in addition to or instead of the above. The or each workstation generates a request message at least once, and the generated request message is transmitted to the central output computer. The central output computer generates a response message, which is transmitted to the workstation. If the workstation has sent a request message but has not received a response message from the central output computer within a specified period of time, the workstation generates a warning and displays it at the workstation in a human-perceivable format. This warning warns the people at the workstation that the workstation is not currently being monitored.

[0117] These two configurations can be combined, for example, as follows: In response to receiving a response message, the central output computer generates a confirmation message. This confirmation message is transmitted to the workstation computer from which the response message originated. If the workstation computer does not receive a confirmation message from the central output computer within a specified period of time after sending the response message, the workstation computer generates an alarm at the workstation and outputs it in a human-perceivable format.

[0118] The invention is described below using an exemplary embodiment.

[0119] Figure 1 two monitoring units and the

[0120] Communication unit; Figure 2 shows the communication unit and a mobile network that provides

[0121] Data connection realized via a central computer;

[0122] Figure 3 shows a first central unit and a second central unit and their respective connection to the mobile network;

[0123] Figure 4 shows a workstation computer of Figure 1 with an internal

[0124] voltage source and two external voltage sources;

[0125] Figure 5 a housing and a trolley for transporting the remaining equipment of the control center;

[0126] Figure 6 shows the housing support and several devices of the control unit on this support;

[0127] Figure 7 shows the overview screen on the carrier and two additional screens.

[0128] Application of the invention

[0129] In the exemplary embodiment, the invention is used to remotely monitor at least one spatial area while work is being performed in or on this area. The area to be monitored is hereinafter referred to as the "workplace." The workplace can, in particular, be an enclosed space, for example, the interior of a container for fluids or a warehouse, or a space of a land vehicle, aircraft, or watercraft. A person performing at least one task at this workplace, for example, welding, is referred to as a "worker."

[0130] Gases that are harmful to humans may be released at the workplace. A worker may also suffer an accident or faint. It is also possible that a worker is not wearing the safety equipment required for that workplace.

[0131] While the worker, or at least one worker, is working at the workstation, a human monitors the workstation remotely. This monitoring human is referred to as the "operator." The area where this operator monitors the workstation is referred to as the "control center."

[0132] The system that supports the operator in remotely monitoring the workstation, optionally multiple workstations simultaneously, is called a "monitoring system." It is possible for the same operator to monitor at least two workstations simultaneously.

[0133] Components of the monitoring system

[0134] The monitoring system includes

[0135] - for each monitored workplace, one component that is installed in or on that workplace,

[0136] - a component in the headquarters and

[0137] - a communication unit (router) for bidirectional data transmission between the component at the workstation and the component at the headquarters.

[0138] The component of the monitoring system that is installed in or at the workplace is hereinafter referred to as the “monitoring unit”.

[0139] Figure 1 shows schematically

[0140] - two monitored workstations A.1, A.2,

[0141] - one monitoring unit 100.1 , 100.2 per monitored workstation A.1 , A.2 and

[0142] - a communication unit (“router”) 10.

[0143] Both workstations A.1, A.2 are each arranged in an enclosed space. Figure 1 schematically shows two entrances E.1, E.2 to the two workstations A.1, A.2. A monitoring unit 100.1, 100.2 comprises

[0144] - at least one camera, optionally several cameras, directed at the workplace, in the case of several cameras, preferably with different viewing directions,

[0145] - at least one gas measuring device, optionally several gas measuring devices, preferably for different target gases, - optionally at least one further sensor, for example a temperature sensor,

[0146] - a workstation computer,

[0147] - optionally an access control unit (“Batch-In / Batch-Out”),

[0148] - optionally a voice input unit comprising a microphone,

[0149] - optionally a voice output unit comprising a loudspeaker,

[0150] - optionally an alarm input element (“alarm button”),

[0151] - optionally an alarm element (“siren”).

[0152] Figure 1 shows the following devices, which in the exemplary embodiment belong to the monitoring unit 100.1 for the workstation A.1:

[0153] - two gas measuring devices 1.1 and 1.2,

[0154] - a camera 2.1 ,

[0155] - an optional temperature sensor 13.1 , which is attached to the gas measuring device 1 .1,

[0156] - a workstation computer 3.1 ,

[0157] - a voice input unit 4.1 ,

[0158] - a 5.1 voice output unit,

[0159] - an access control unit 6.1 and

[0160] - an alarm input element 7.1 .

[0161] In the implementation shown, the workstation computer 3.1 and the gas measuring device 1.2 are arranged outside the enclosed space A.1, while the other devices are each mounted inside on a wall within the enclosed space. A hose 8 leads from the gas measuring device 1.2 into the enclosed space A.1. The gas measuring device 1.2 can draw a gas sample from the enclosed space A.1 through the hose 8. It is also possible for all devices of the monitoring unit 100.1 to be arranged inside the enclosed space A.1. It is also possible for the workstation computer 3.1 to be arranged in the enclosed space A.1. This has the advantage that a user can read an indicator light on the workstation computer 3.1 and / or operate an actuating element without leaving the enclosed space A.1. On the other hand, the workstation computer 3.1 must then, in many cases, meet higher explosion protection requirements.

[0162] Figure 1 shows the following devices, which in the exemplary embodiment belong to the monitoring unit 100.2 for the workstation 1.2:

[0163] - a gas measuring device 1.3, which is fixed to a wall inside the workstation A.2,

[0164] - a gas measuring device 1.4, which is located on the floor outside the workstation A.2 and in front of the entrance E.2,

[0165] - a camera 2.2, which is mounted inside a wall of the workstation A.2,

[0166] - a camera 2.3, which is mounted inside the ceiling of the workstation A.2,

[0167] - an optional temperature sensor 13.2,

[0168] - a workstation computer 3.2,

[0169] - a voice input unit 4.2,

[0170] - a speech output unit 5.2,

[0171] - an access control unit 6.2 and

[0172] - an alarm input element 7.2.

[0173] Again, workstation computer 3.2 is located outside the monitored workstation A.2, while the remaining devices are located in workstation A.2. It is also possible that a workstation computer 3.1 or 3.2 is located in workstation A.1, A.2.

[0174] In the embodiment shown in Figure 1, the gas detectors 1.1 and 1.2, the temperature sensor 13.1, the camera 2.1, the voice input unit 4.1, the voice output unit 5.1, and the alarm input element 7.1 are connected wirelessly, in particular via radio waves, to the workstation computer 3.1. The gas detector 1.3, the cameras 2.2 and 2.3, the voice input unit 4.1, the voice output unit 5.1, and the alarm input element 7.1 are connected wirelessly to the workstation computer 3.2. This makes it easier to position each device in a suitable location in or at the monitored workstation A.1, A.2. In another implementation, the camera 2.1, the voice input unit 4.1, the voice output unit 5.1, the access control unit 6.1, and / or the alarm input element 7.1 are supplied with electrical power by the workstation computer 3.1. It is possible that the camera 2.1, the voice input unit 4.1, the voice output unit 5.1,1, the access control unit 6.1 and the alarm input element 7.1 are detachably inserted, for example screwed, into a housing of the workstation computer 3.1.

[0175] Preferably, each camera 2.1, 2.2, 2.3 includes its own light source to illuminate the workstation A.1, A.2. It is possible for the light source to be permanently switched on and to permanently illuminate the workstation A.1, A.2. It is also possible for a worker at the workstation A.1, A.2 or an operator in the control center to switch the light source on and off.

[0176] Preferably, each workstation computer 3.1, 3.2 comprises indicator lights and control elements. In one embodiment, each workstation computer 3.1, 3.2 additionally comprises an output unit on which alarms from a connected gas measuring device 1.1, ..., 1.4 are output, preferably visually.

[0177] The component of the monitoring system installed in the control center includes

[0178] - an overview screen,

[0179] - optionally at least one additional screen,

[0180] - optionally a voice output unit comprising a headset,

[0181] - optionally a voice input unit comprising a microphone,

[0182] - a central output computer and

[0183] - another communication unit.

[0184] Figures 2 and 3 schematically show the communication unit 10, a first central unit Z, and a second central unit T. The communication unit 10 is connected, or at least temporarily connectable, to the central units Z and T via the schematically shown Internet I. The connection via the Internet I implements a bidirectional wireless data connection. This data connection is established with the aid of a central computer 15. The communication unit 10 is located outside the workstations A.1 and A.2 and therefore does not necessarily need to meet such high explosion protection requirements as the devices in a workstation A.1, A.2.

[0185] The following devices of the first central unit Z are shown:

[0186] - a central output computer 20, which in the exemplary embodiment has the form of a laptop with its own screen, a mouse 50 and its own keyboard,

[0187] - a separate communication unit (router) 44,

[0188] - one headphone 21 ,

[0189] - a microphone 27 attached to the headphones 21,

[0190] - an overview screen 22,

[0191] - two further screens 23.1, 23.2, which in one embodiment are movably connected to the overview screen 22 and in another embodiment are located next to the overview screen 22, and

[0192] - an output program 48, for example a web browser, which is installed on the central output computer 20.

[0193] The headphones 21, the microphone 27 and the screens 22, 23.1, 23.2 are each connected to the central output computer 20 by a data connection. The output program 48 is installed on the central output computer 20 and can be executed there.

[0194] The central output computer 20 may also include a separate keyboard and / or additionally a mouse 50.

[0195] Two windows 24.1 and 24.2 are displayed on overview screen 22. Window 24.1 displays an image sequence AT from workstation A.1, and window 24.2 displays an image sequence A.2' from workstation A.2. A frame 27.1 is arranged around window 24.1, and a frame 27.2 is arranged around window 24.2.

[0196] The second central unit T is implemented using a tablet Tb. This tablet Tb functions as the second central output computer and includes a screen 28 and is connected or connectable to a headset 21. The headset 21 is connected to a microphone 27. An output program 49, for example, a web browser, is installed on the tablet Tb. Two windows 24.1 for workstation A.1 and 24.2 for workstation A.2 are also displayed on the screen 28 of the tablet Tb.

[0197] The central output computer 20 is capable of controlling the or each screen 22, 23.1, 23.2 as well as the headphones 21. For this purpose, the output computer 20 uses an output program 48, 49 and the processing 17 described above, which was generated by the central computer 15. Optionally, an image evaluation unit is installed on the central output computer 20. This image evaluation unit automatically evaluates image signals from at least one camera, preferably each camera 2.1, 2.2, 2.3. One goal of the evaluation is to detect whether the images from a workstation A.1, A.2 show at least one moving person or not. In some cases, image evaluation can also be used to detect an undesirable event, such as a fire.

[0198] In one embodiment, the entire component of the monitoring system installed in the control center is implemented on a portable computer, in particular a smartphone or tablet. Corresponding components of the portable computer function as the overview screen, the voice output unit, the voice input unit, and the central output computer. This is shown in Figure 3 as an example for the second control center T on the tablet Tb.

[0199] Functions of the devices of a monitoring unit

[0200] The functions of these devices are described below.

[0201] The or each gas measuring device 1.1, 1.2, 1.3, 1.4 measures the concentration of at least one target gas at the monitored workstation A.1, A.2, optionally the respective concentration of several target gases, and compares the or each measured target gas concentration with a predetermined upper concentration limit. If the or a target gas concentration is above the upper concentration limit, the gas measuring device 1.1, 1.2, 1.3, 1.4 automatically generates an alarm. The measured target gas concentrations and alarms are transmitted to the central units Z, T and output in at least one way that is perceptible to a person. It is also possible for only the measured target gas concentrations to be transmitted to the central units Z, T, and for the output computer 20 to evaluate the transmitted measured values ​​and generate the alarms.

[0202] In one embodiment, the or at least one gas measuring device 1.1, 1.3, 1.4 is located in or in front of the monitored workstation A.1, A.2, and gas diffuses into the interior of the gas measuring device 1.1, 1.3, 1.4 or is sucked in, e.g. by a pump of the gas measuring device 1.1, 1.3, 1.4. In another embodiment, at least one gas measuring device 1.2 is connected to a hose 8. The hose 8 is led into the interior of a workstation A.2 in the form of an enclosed space. The gas measuring device 1.2 is arranged outside this enclosed space A.2 and permanently sucks gas in from the space through the hose 8, preferably with its own pump. As a result, the gas measuring device 1.2 is not exposed to mechanical and chemical influences in the enclosed space.

[0203] The temperature sensor 131, 133, 10.2 measures the temperature at the monitored workstation A.1, A.2. In one embodiment, the temperature sensor 13.1, 13.2 can automatically generate an alarm if the measured temperature lies outside a predefined value range. This alarm indicates that the monitored workstation is too hot or too cold.

[0204] The or each camera 2.1, 2.2, 2.3 generates an image signal, preferably a sequence of images, from workstation A.1, A.2. The or each image signal of a camera 2.1, 2.2, 2.3 is transmitted to the central stations Z, T and displayed there on the respective screen or at least one screen.

[0205] In one embodiment, at least one camera 2.1, 2.2, 2.3 has a light source, wherein this light source is designed to illuminate the monitored workstation A.1, A.2. The light source preferably emits light in the visible range, but it can also emit light in the infrared range. In one embodiment, this light source can be switched on and off by an external control. In one embodiment, each camera 2.1, 2.2, 2.3 can be switched on and off by an external control in order to save energy.

[0206] Preferably, the or each camera 2.1, 2.2, 2.3 each has at least one, preferably several, parameters whose respective values ​​can be changed by external control. Examples of these parameters are:

[0207] - the refresh rate (“frames per second”),

[0208] - the resolution, i.e. the number of pixels per image,

[0209] - another parameter that affects the amount of data per unit of time required to transmit an image signal from camera 2.1, 2.2, 2.3,

[0210] - the direction of view, the angle of view, the image scale and whether the optional light source is switched on or off.

[0211] In one embodiment, each camera 2.1, 2.2, 2.3 is configured during use such that the viewing direction remains constant as long as the camera is mounted in or at the workstation A.1, A.2. In another embodiment, an actuator is assigned to at least one camera. This actuator can move the camera 2.1, 2.2, 2.3 and thereby change the viewing direction of the camera 2.1, 2.2, 2.3. This actuator can preferably be controlled externally.

[0212] In one embodiment, each camera 2.1, 2.2, 2.3 has a fixed focal length and thus a fixed image scale. In another embodiment, the focal length and thus the image scale of the camera 2.1, 2.2, 2.3 can be changed, preferably by external control.

[0213] In a preferred implementation, each camera 2.1, 2.2, 2.3 comprises a photosensor, its own image processing unit (image processor) and its own control unit, and optionally also its own power supply unit. The photosensor is capable of generating digital images as a function of electromagnetic waves, in particular light rays, that strike the camera 2.1, 2.2, 2.3. In one embodiment, the design of the camera 2.1, 2.2, 2.3 determines how many image points (pixels) a digital image has. In another embodiment, the resolution can be changed by external control. The refresh rate is the frequency at which the photosensor generates and delivers digital images. If the refresh rate is too low, the undesirable event that the image signal is displayed jerkily on a screen can occur.

[0214] The image processing unit generates an image signal from the sequence of digital images generated by the photosensor. The image processing unit preferably applies a compression algorithm. In order to transmit this image signal to a spatially distant receiver, a certain amount of data per unit of time (bit rate) is required. This required bit rate depends on the image processing unit, in particular on the compression algorithm used. At least one parameter influences the function of the image processing unit. This parameter is, in particular, a parameter of the compression algorithm. Very strong compression can result in details in a visual representation of the image signal being unrecognizable. The parameter of the image processing unit generally influences the bit rate required to transmit the image signal from the camera 2.1, 2.2, 2.3.It is possible that there are several such parameters that influence the compression algorithm and can be changed independently of each other.

[0215] A worker can enter a voice message into the voice input unit 4.1, 4.2 at workstation A.1, A.2. This voice message is output by the voice output unit 21 in the control centers Z, T to the operator, preferably via headset 21. Accordingly, the operator can enter a voice message, and this voice message is transmitted and output to the worker, preferably via loudspeaker 5.1, 5.2. This allows the worker and the operator to exchange voice messages.

[0216] When a worker enters the workstation A.1, A.2, they log in to the access control unit 6.1, 6.2, for example by holding an RFID chip on a card to an RFID reader of the access control unit 6.1, 6.2. When they leave the workstation A.1, A.2 again, they log out in the same way. When a worker logs in, the access control unit 6.1, 6.2 determines which person has logged in or logged out. In one implementation, the workstation computer 3.1, 3.2 determines how many and which people are currently at the workstation A.1, A.2 according to the access control unit 6.1, 6.2. This information is transmitted to the control centers Z, T and output there in a form that can be perceived by a person. In another implementation, the respective identification of a worker who has logged in or logged out is transmitted to the central output computer 20.The central output computer 20 uses these transmitted data to count how many workers are currently in or at the monitored workstation A.1, A.2.

[0217] It is possible that a worker enters workstation A.1, A.2 without logging in to the access control unit 6.1, 6.2. Furthermore, it is possible that the access control unit 6.1, 6.2 is defective or that data transmission is interrupted. Therefore, workstation A.1, A.2 is preferably continuously monitored during the period in which work is being or can be performed there.

[0218] Using the alarm element 7.1, 7.2, a worker can signal that an alarm should be triggered at workstation A.1, A.2 in a human-perceivable form. A corresponding alarm message is generated, transmitted to the control centers Z, T, and output to the operator. Preferably, a voice connection is also automatically established between workstation A.1, A.2 and the control centers Z, T.

[0219] Data transmission within the monitoring unit

[0220] The or each gas measuring device 1.1, 1.2, 1.3, 1.4 as well as the or each camera 2.1, 2.2, 2.3 and the or each optional temperature sensor 13.1, 13.2 are connected to the workstation computer 3.1, 3.2 via cable and / or wirelessly, in particular via radio waves. Bluetooth is preferably used as the wireless data connection between the or one gas measuring device 1.1, 1.2, 1.3, 1.4 and the workstation computer 3.1, 3.2; for the or each camera 2.1, 2.2, 2.3, WLAN, e.g. WiFi, or also Bluetooth is preferably used.

[0221] The workstation computer 3.1, 3.2 preferably comprises a plurality of indicator lights in the form of LEDs. Some of these indicator lights indicate whether or not a data connection is currently established between the workstation computer 3.1, 3.2 and the other devices of the monitoring unit 100.1, 100.2. In addition, the workstation computer 3.1, 3.2 preferably comprises a relatively small screen on which error messages and other status messages are output, for example the current fill level of a power supply unit for the workstation computer 3.1, 3.2 and / or information about which people are currently located at the workstation A.1, A.2 according to signals from the access control unit 6.1, 6.2. Optionally, an alarm from a connected gas measuring device 1.1, 1.2, 1.3, 1.4 is also output on this screen.

[0222] In one embodiment, the workstation computer 3.1, 3.2 automatically detects whether a gas measuring device 1.1, 1.2, 1.3, 1.4 and / or a camera 2.1, 2.2, 2.3 are connected with a cable. If this is not the case, the workstation computer automatically establishes a wireless data connection via radio waves. In one embodiment, a gas measuring device 1.1, 1.2, 1.3, 1.4 and / or a camera 2.1, 2.2, 2.3 can be mechanically connected to the workstation computer 3.1, 3.2, for example using a thread or a plug. This connection can preferably be removed again.

[0223] In one embodiment, the or each camera 2.1, 2.2, 2.3 is connected to the associated workstation computer 3.1, 3.2 via a cable. On the one hand, the image signal from the camera 2.1, 2.2, 2.3 is transmitted to the workstation computer 3.1, 3.2 via this cable. On the other hand, in one embodiment, the camera 2.1, 2.2, 2.3 is supplied with electrical power from the workstation computer 3.1, 3.2 via this cable. This embodiment eliminates the need to provide the camera 2.1, 2.2, 2.3 with its own power supply unit. It is also possible that the or each gas measuring device 1.1, 1.2, 1.3, 1.4 is connected to the workstation computer 3.1, 3.2 via a cable and that, on the one hand, measured values ​​of the gas measuring device 1.1, 1.2, 1.3, 1.4 are transmitted to the workstation computer 3.1, 3.2 via this cable.

[0224] In one implementation, the workstation computer 3.1, 3.2 supplies the gas measuring device 1.1, 1.2, 1.3, 1.4 with electrical energy via the cable. Preferably, however, the gas measuring device 1.1, 1.2, 1.3, 1.4 comprises its own power supply unit, and the measured values ​​of the gas measuring device 1.1, 1.2, 1.3, 1.4 are transmitted wirelessly, in particular via radio waves, to the workstation computer 3.1, 3.2.

[0225] In one embodiment, a camera 2.1, 2.2, 2.3 and / or a gas measuring device 1.1, 1.2, 1.3, 1.4 and / or the workstation computer 3.1, 3.2 are capable of automatically detecting whether they are connected to the workstation computer 3.1, 3.2 via a cable and whether or not electrical energy is being transmitted via this cable. If this is not the case, the camera 2.1, 2.2, 2.3 or the gas measuring device 1.1, 1.2, 1.3, 1.4 switches to its own

[0226] Power supply unit, or the devices are switched accordingly by external control. This embodiment further increases the flexibility of the monitoring system according to the invention. In particular, it is possible to supply the camera 2.1, 2.2, 2.3 and / or the gas measuring device 1.1, 1.2, 1.3, 1.4 with electrical energy from the workstation computer 3.1, 3.2 if the distance is short enough. On the other hand, it is possible to install the camera 2.1, 2.2, 2.3 and / or the gas measuring device 1.1, 1.2, 1.3, 1.4 at a relatively large distance from the workstation computer 3.1, 3.2, without the length of a cable limiting the distance to the workstation computer 3.1, 3.2.

[0227] Preferably, the or each workstation computer 3.1, 3.2 checks whether or not a data connection still exists to each other device of the monitoring unit 100.1, 100.2. Particularly preferably, the workstation computer 3.1, 3.2 regularly queries each connected device. If a device does not respond, the workstation computer 3.1, 3.2 preferably generates a corresponding alarm message. The alarm message is transmitted to the central output computer 20 and output there in a human-perceivable form.

[0228] As already explained, harmful gases, particularly explosive gases, can escape at a workplace A.1, A.2 to be monitored. Therefore, all components of the monitoring unit 100.1, 100.2 for this workplace A.1, A.2 are preferably designed as intrinsically safe devices. In one implementation, each device is certified according to ATEX and / or lECx and / or complies with the ISO 80079-36 and -37 standards. This fulfills a relatively high requirement for explosion protection. In an intrinsically safe device, the electrical current and electrical power are limited at all times by suitable components in the device. This means that the device cannot trigger an explosion in any situation or under any operating conditions. In particular, the device does not generate sparks that could escape to the outside and trigger an explosion. Furthermore, an intrinsically safe device does not heat up so much that the heated device could trigger an explosion.

[0229] The intrinsically safe design eliminates the need to enclose the device in a pressure-resistant metal housing and to provide a fluid-tight seal from the environment. This would often be impossible with a gas detector, for example, and would also significantly increase the weight of the device.

[0230] Design of the monitoring unit as a portable unit

[0231] In the exemplary embodiment, the workstation A.1, A.2 does not need to be monitored permanently, but only during a period in which at least one worker is carrying out work there. Outside of this period, no one is at or in the workstation A.1, A.2. Before the work to be monitored begins, a monitoring unit 100.1, 100.2 is set up at and / or in the workstation A.1, A.2 to be monitored, a data connection to the control center Z, T is established, and the workstation A.1, A.2 is monitored from the control centers Z, T. After monitoring has ended, the devices of the monitoring unit 100.1, 100.2 are disconnected from one another again. Because all devices of a monitoring unit 100.1, 100.2 are designed as intrinsically safe devices, it is possible to assemble the devices at or in the workstation A.1, A.2 to be monitored to form the monitoring unit 100.1, 100.2 and to separate them from each other later.Of course, it is also possible to combine the devices outside the workstation A.1, A.2 to form the monitoring unit 100.1, 100.2 and the.

[0232] Monitoring unit 100.1, 100.2 to be transported to the workstation A.1, A.2.

[0233] The devices of a monitoring unit 100.1, 100.2 are preferably designed as portable devices. Therefore, in many cases, neither a vehicle nor a crane is required to transport the devices to the workstation A.1, A.2. Particularly preferably, the combined weight of all devices of a monitoring unit 100.1, 100.2 is less than 20 kg, particularly preferably less than 10 kg. Therefore, a single person can carry all devices of a monitoring unit 100.1, 100.2 to the workstation A.1, A.2 to be monitored and assemble them there. A preferred contribution to this result is that each device of a monitoring unit 100.1, 100.2 is designed as an intrinsically safe device and therefore does not necessarily have a pressure-resistant housing. Such a pressure-resistant housing is often relatively heavy.

[0234] It is also possible for a person to assemble the devices into the monitoring unit 100.1, 100.2 near the workstation A.1, A.2 to be monitored and to carry the assembled monitoring unit 100.1, 100.2 to the workstation. Preferably, no aids at all or only standard tools are required to assemble the devices into the monitoring unit 100.1, 100.2.

[0235] In one embodiment, the devices belonging to a monitoring unit 100.1, 100.2 are placed on the floor at or in the workstation A.1, A.2. In a preferred embodiment, however, they are detachably attached. In particular, a device of a monitoring unit 100.1, 100.2 can be detachably attached to a component of the workstation A.1, A.2 in one of the following alternative implementations:

[0236] - The device to be fixed comprises at least one permanent magnet, and this is placed on a sufficiently large vertical or inclined magnetic surface of the workstation A.1, A.2.

[0237] - The device includes a clamp mount with a mounting plate. This clamp mount is removably mounted in a suitable recess or on a suitable fastening element of the workstation A.1, A.2.

[0238] - The device includes a fastening element that allows the device to be removably attached to a flange connection. Such a flange connection is often found at a monitored workstation A.1, A.2. - The device includes a suction element, in particular a suction cup. This suction element is pressed onto a sufficiently large, stable, and clean surface at the workstation A.1, A.2.

[0239] Preferably, at least one device comprises at least two of these possible fastening elements, i.e. a permanent magnet and / or a clamp fastening and / or a fastening element for a flange connection and / or a suction element, so that in many cases the device can be releasably fastened in at least one, preferably at least two, of the ways just described and does not need to be placed on the floor.

[0240] Data transmission between the monitoring unit and the control center

[0241] On the one hand, the communication unit 10 is in a bidirectional data connection with the workstation computer 3.1, 3.2 of a

[0242] Monitoring unit 100.1, 100.2. On the other hand, it is in a bidirectional data connection with the central output computer 20. The same communication unit 10 can simultaneously be in a bidirectional data connection with at least two workstation computers 3.1, 3.2, each of which has a bidirectional data connection, see Figure 1.

[0243] The or each connected workstation computer 3.1, 3.2 is connected to the communication unit 10 via cable or wirelessly, in particular via WiFi. In one embodiment, a 10 Mbit or 100 Mbit Ethernet connection can be established using the cable. In one embodiment, the communication unit 10 can automatically detect whether a workstation computer 3.1, 3.2 is connected to the communication unit 10 via a cable. If the communication unit 10 detects a connected cable, data is exchanged between the workstation computer 3.1, 3.2 and the communication unit 10 via this cable, otherwise wirelessly, in particular via radio waves. It is possible for the communication unit 10 to additionally supply a workstation computer 3.1, 3.2 with electrical energy via a cable.

[0244] In one embodiment, the communication unit 10 is also detachably mounted, particularly preferably in the vicinity of the monitored workstation A.1, A.2. The mounting elements described above with reference to the devices of the monitoring unit 100.1, 100.2 can also be used for the communication unit.

[0245] As already explained, it is possible to connect the same communication unit 10 to at least two different workstation computers 3.1, 3.2 and thus to at least two different monitoring units 100.1, 100.2. Preferably, a series connection is implemented according to the "daisy chain" principle: a first workstation computer 3.1 is connected on the one hand to a second workstation computer 3.2 and on the other hand to the communication unit 10, see Figure 1. The series connection eliminates the need for a star connection and requires fewer data connections. Preferably, signals from the second workstation computer 3.2 are transmitted via the first workstation computer 3.1 to the communication unit 10 and onward to the central unit Z, T, and conversely, messages from the central units Z, T are transmitted to the communication unit 10 and onward via the first workstation computer 3.1 to the second workstation computer 3.2.This series connection is indicated in Figure 1.

[0246] In the exemplary embodiment, the communication unit 10 is wirelessly connected to the central output computer 20 and to the tablet Tb of the mobile control center T via the Internet I and a public mobile radio network, for example via LTE (Long Term Evolution) or 5G. Figure 2 schematically shows the Internet I, a central computer 15 and a cloud through which the communication unit 10 is connected to both the stationary control center Z and the mobile control center T, see Figure 3. The two control centers Z, T are therefore connected in parallel. In one embodiment, the central computer 15 receives the respective signals from the or each monitoring unit 100.1, 100.2 and stores them at least temporarily.

[0247] In the exemplary embodiment, a monitoring system area 16 is provided on the central computer 15 and used to monitor the two workstations A.1, A.2. It is possible for the monitoring system area 16 to be permanently assigned to the monitoring system according to the invention. Preferably, however, this monitoring system area 16 is only used for a predetermined period of time in order to implement functions of the monitoring system according to the invention. The work at the workstations A.1, A.2 takes place within this predetermined period of time. It is of course possible to subsequently monitor at least one further workstation within this period of time and to use the same monitoring system area 16 for this purpose. Preferably, after the end of this period of time, the or each program as well as all data in the monitoring system area 16 are deleted, and the monitoring system area is made available for other applications.

[0248] The monitoring system area 16 includes a processing program 18, for example a web server. This processing program 18 can be executed on the central computer 15. When executed, it processes the signals from the devices at the workstations A.1, A.2 and generates a processing 17, i.e., a set of data that can be output in a form that can be perceived visually and / or acoustically and / or haptically by a person. An output program 48, 49, in particular a web browser, is installed on the central output computer 20. The central output computer 20 receives the processing 17 from the central computer 15 via the Internet and causes the output program 48, 49 to display the processing 17 in the first central unit Z. This is described in more detail below. The tablet Tb of the second central unit T receives the same processing 17 and displays it.

[0249] The use of a public mobile radio network I has the following advantages in particular compared to the alternative of establishing a microwave link: It is not necessary to ensure a permanent line of sight between the communication unit 10 and the central output computer 20. Furthermore, in many cases it is not necessary to precisely align the antennas of a workstation computer 3.1, 3.2 and / or the communication unit 10. Furthermore, in many cases a significantly greater distance can be bridged between the communication unit 10 and the control centers Z, T. This provides greater flexibility as to where a control center Z, T can be positioned relative to a workstation A.1, A.2 to be monitored. Furthermore, it is possible to monitor several workstations in one and the same control center Z, T, whereby these workstations are relatively far apart from one another.

[0250] The or each workstation computer 3.1, 3.2 is capable of transmitting data from the connected devices to the central computer 15. In one implementation, the central computer 15 regularly queries each workstation computer 3.1, 3.2.

[0251] In one embodiment, a web server is installed on the central computer 15. A display program in the form of a web browser 48 is installed on the central output computer 20, and a display program 49 is installed on the tablet Tb. In one implementation, the or each monitoring unit 100.1, 100.2 is assigned a unique internet address. In another implementation, a unique internet address is assigned to the communication unit 10. In a preferred embodiment, a unique internet address is assigned to the monitoring system area 16 on the central computer 15. After a user has entered this internet address into the web browser 48, 49, the central computer 15 transmits the above-described processing 17 of signals received from the workstation computer 3.1, 3.2 of this monitoring unit 100.1, 100.2 or from the communication unit 10, to the central output computer 20 and to the tablet Tb, in particular image signals, alarms, and other measurement results. This configuration makes it possible to quickly establish a connection between the central output computer 20 and the tablet Tb on the one hand, and the central computer 15 on the other.

[0252] At the start of an operation and during the operation, it must be ensured that a data connection is actually established between the or each monitoring unit 100.1, 100.2 and the control centers Z, T. If it is determined that no data connection is established between a monitoring unit 100.1, 100.2 and a control center Z, T, an alarm is automatically triggered and issued in at least one form that can be perceived by a person, preferably both at the workstation A.1, A.2 by the monitoring unit 100.1, 100.2 and in the control center Z, T. An alarm is preferably also generated and issued if a gas measuring device 1.1, 1.2, 1.3, 1.4 or a camera 2.1, 2.2, 2.3 has failed.

[0253] An alarm triggered at or for a workplace A.1, A.2 preferably includes the information that this workplace A.1, A.2 is to be evacuated.

[0254] Various configurations are possible as to how it is checked whether a data connection has been established and still exists between the central units Z, T and a workstation A.1, A.2.

[0255] In one embodiment, the or each workstation computer 3.1, 3.2 repeatedly generates a message, such that there is at most a predetermined time interval between the generation of two consecutive messages. For example, messages are generated at a fixed frequency. Each message is transmitted to the central units Z, T. The central output computer 20 in the central units Z, T detects the undesirable event that there is no data connection between a workstation computer 3.1, 3.2 and the central output computer 20 or the tablet Tb if at least one of the following events is detected:

[0256] - There is no message at all from a workstation computer 3.1, 3.2.

[0257] - The central output computer 20 / the tablet Tb has received a message from a workstation computer 3.1, 3.2, and after this reception, a period of time of a predetermined duration has elapsed without a further message being received from this workstation computer 3.1, 3.2.

[0258] In a further embodiment, the central output computer 20 / the tablet Tb repeatedly generates a message for each workstation computer 3.1, 3.2, again in such a way that the maximum time interval between the generation of two consecutive messages is the predetermined time interval. Each message is transmitted to the relevant workstation computer 3.1, 3.2. The workstation computer 3.1, 3.2 detects the event that there is no data connection to a central station Z, T if there is no message at all from the central station Z, T or if a period of time has elapsed after the receipt of the last message from the central station Z, T, which period has a predetermined time duration. The two embodiments just described can be combined with one another.

[0259] In a further embodiment, the following steps are carried out at the beginning of an operation, and these steps are preferably carried out again at least once during the operation, preferably at a fixed frequency:

[0260] - The central output computer 20 and the tablet Tb each generate a request message for each workstation computer 3.1, 3.2. This request message is transmitted to the workstation computer 3.1, 3.2 via the central computer 15 and the communication unit 10, unless a fault has occurred.

[0261] - As soon as the workstation computer 3.1, 3.2 receives this request message, it generates a response message. This response message is transmitted to the central output computer 20 and to the tablet Tb.

[0262] - The central output computer 20 and the tablet Tb check whether, after the step of transmitting a request message to a workstation computer 3.1, 3.2 and after a specified time period has elapsed, a response message has been received from this workstation computer 3.1, 3.2. If no response message has been received, the central output computer 20 / the tablet Tb generates an alarm naming this workstation A.1, A.2.

[0263] - Conversely, if a workstation 3.1, 3.2 does not receive a request message after activation, the workstation 3.1, 3.2 preferably also generates an alarm. This alarm indicates that the respective workstation A.1, A.2 may not currently be able to be monitored.

[0264] Change in required bandwidth

[0265] The wireless connection between the communication unit 10 and the control centers Z, T uses the Internet I and the public mobile network without influencing them. Therefore, this wireless connection is heavily dependent on the bandwidth currently available for data transmission between the communication unit 10 and the control centers Z, T. Various events in the vicinity of a monitored workstation A.1, A.2 can lead to other communication units consuming a lot of bandwidth and therefore significantly reducing the bandwidth still available for data transmission between the communication unit 10 and the control centers Z, T. If at all possible, the monitoring of the or each connected workstation A.1, A.2 should be maintained despite changing bandwidth.

[0266] Most of the bandwidth is required to transmit the respective image signal from the or each camera 2.1, 2.2, 2.3 to the control centers Z, T. Significantly less bandwidth is required to transmit the respective signal and, if applicable, an alarm from each gas detector 1.1, 1.2, 1.3, 1.4. The event that only a lower bandwidth is available than previously and / or the event that insufficient bandwidth is available are automatically detected. Preferably, the value of at least one data transmission parameter that correlates with the available bandwidth is determined. In particular, the following parameters are examined:

[0267] - the latency - if this is greater than a given upper limit, there is too little bandwidth available, and / or

[0268] - the loss of data packets during transmission (packet loss and packet drop).

[0269] As already explained, the image signal from the or each camera 2.1, 2.2, 2.3 at the monitored workstation A.1, A.2 requires the greatest bandwidth. The detection of insufficient bandwidth triggers the step of reducing the bandwidth of the or each camera 2.1, 2.2, 2.3 that is currently supplying an image signal to the communication unit 10. The reducing the bandwidth of the camera 2.1, 2.2, 2.3 comprises the step of controlling the camera 2.1, 2.2, 2.3 from outside and, through the control, assigning a different value to at least one bandwidth-relevant parameter of the camera 2.1, 2.2, 2.3, i.e., a parameter that influences the bit rate required to transmit the image signal from the camera 2.1, 2.2, 2.3 to the control centers Z, T.

[0270] In one implementation, at least one of the following parameters of a camera 2.1, 2.2, 2.3 is changed by controlling it with the aim of reducing the required bandwidth: - The resolution, i.e. the number of pixels per image, is reduced.

[0271] - The refresh rate, i.e. the number of images generated per second (“frames per second”), is reduced.

[0272] - The algorithm that the image processing unit applies to the images from the photosensor is modified in such a way that the images are compressed more intensively, thus making a single image occupy a smaller amount of data.

[0273] Preferably, each camera 2.1, 2.2, 2.3 is designed so that the resolution, the frame rate and the parameters for the image processing algorithm can be changed independently of one another by a corresponding external control.

[0274] As already explained, according to a preferred embodiment, each camera 2.1, 2.2, 2.3 comprises a photosensor and a

[0275] Image processing unit. The photosensor generates a sequence of digital images at a variable refresh rate ("frames per second"). The image processing unit generates the image signal from the sequence of digital images. The image signal is transmitted to the central units Z, T via the workstation computers 3.1, 3.2 and the communication unit 10. To transmit this image signal, a data volume per unit of time (bit rate) is required. This bit rate is influenced by a variable parameter of the image processing unit, in particular by a parameter of a compression algorithm that the image processing unit applies. The resolution, the refresh rate, and the parameter that affects the bit rate are three externally variable bandwidth-relevant parameters of the camera 2.1, 2.2, 2.3.

[0276] The step of assigning a possibly modified value to each of the parameters just mentioned and using this value is triggered automatically and reduces the bandwidth required to transmit image data from the respective camera 2.1, 2.2, 2.3 to the communication unit 10 and further via a public mobile network to the control centers Z, T. Such a measure is preferably triggered when an indication of low bandwidth is detected. In one embodiment, at least one measure to reduce the required bandwidth is also carried out when at least one of the following events is detected:

[0277] - According to the signal from access control unit 6.1, 6.2, there is currently no worker in or at the monitored workstation A.1, A.2. Note: It is possible that a worker is present there but has not logged in to access control unit 6.1, 6.2. Therefore, even in this situation, images are transmitted to control centers Z, T, and camera 2.1, 2.2, 2.3 is not switched off.

[0278] - An image processing unit (not shown) evaluates images from the camera

[0279] 2.1, 2.2, 2.3 and has detected through analysis that no movement has occurred in or at workstations A.1, A.2 for a specified period of time. Even in this situation, images continue to be transmitted to the central stations Z, T.

[0280] - An operator in a control center Z, T has arranged that for a camera 2.1 ,

[0281] 2.2, 2.3, the value of a bandwidth-relevant parameter is reduced. One reason may be that the operator requires an image sequence from another camera 2.1, 2.2, 2.3, whose transmission requires a higher bandwidth.

[0282] It is possible that at least two cameras 2.1, 2.2, 2.3 are connected to the same communication unit 10, for example because a monitoring unit 100.2 comprises two cameras or because two different monitoring units 100.1, 100.2, each with a camera 2.1, 2.2, 2.3, are connected to the communication unit 10 at the same time, see Figure 1. In one embodiment, the at least two connected cameras 2.1, 2.2, 2.3 are turned down in the same way. In another embodiment, a request is directed to the operator in one or each control center Z, T to select a connected camera 2.1, 2.2, 2.3. The or at least one selected camera 2.1, 2.2, 2.3 is turned down, or the or at least one non-selected camera 2.1, 2.2, 2.3 is turned down.

[0283] Various embodiments are possible as to which person or device triggers the turning down of a camera 2.1, 2.2, 2.3. As already explained, the operator can trigger the step of turning down each camera connected to a workstation computer 3.1, 3.2 selected by the user, or a camera 2.1, 2.2, 2.3 selected by the user, from a central station Z, T. Preferably, the operator is notified that there is insufficient bandwidth available, and the operator selects at least one monitored workstation A.1, A.2. The workstation computer 3.1, 3.2 of the selected workstation A.1, A.2 then turns down the camera or at least one, preferably every camera 2.1, 2.2, 2.3 of the selected workstation A.1, A.2.

[0284] In one implementation, the central output computer 20 and the tablet Tb regularly query the central computer 15 as to which bandwidth is available for a data transmission from a workstation computer 3.1, 3.2 to the central output computer 20 or the tablet Tb, respectively. The central output computer 20 and the tablet Tb transmit the requested bandwidth to the workstation computer 3.1, 3.2. It is also possible for at least one workstation computer 3.1, 3.2 to regularly query the central computer 15.

[0285] In a preferred embodiment, a workstation computer 3.1, 3.2 is capable of automatically detecting that the available bandwidth is insufficient. Lack of bandwidth generally results from the fact that the public mobile network I used does not provide sufficient bandwidth to transmit data from the communication unit 10 to the central stations Z, T. The connection between the workstation computer 3.1, 3.2 and the

[0286] Communication unit 10 is generally not impaired by a low bandwidth, in particular not by a low bandwidth in the public mobile radio network I used. After the workstation computer 3.1, 3.2 has detected the low bandwidth for a workstation A.1, A.2, it controls the or at least one, preferably every connected camera 2.1, 2.2, 2.3 at the workstation A.1, A.2 in order to regulate down the camera 2.1, 2.2, 2.3 and thereby reduce the required bandwidth.

[0287] The method just described requires neither a message exchange between different workstations 3.1, 3.2 nor a message exchange between a workstation 3.1, 3.2 and the communication unit 10 in order to reduce the bandwidth. Rather, each workstation 3.1, 3.2 reduces the bandwidth independently of every other workstation 3.2, 3.1 and also independently of the

[0288] Communication unit 10 the bandwidth required to transmit image signals from the connected cameras 2.1, 2.2, 2.3 to the central units Z, T.

[0289] If a workstation computer 3.1, 3.2 has detected a low bandwidth, it regulates down each connected camera 2.1, 2.2, 2.3 as just described with the aim of reducing the respective required bandwidth. The workstation computer 3.1, 3.2 causes a value of at least one bandwidth-relevant parameter that influences the bandwidth of a connected camera 2.1, 2.2, 2.3 to be changed with the aim of reducing the required bandwidth. The workstation computer 3.1, 3.2 preferably checks at least once what bandwidth is available after this reduction. If there is still insufficient bandwidth available, the workstation computer 3.1, 3.2 again regulates down at least one connected camera 2.1, 2.2, 2.3 with the aim of reducing the bandwidth. Preferably, the workstation computer 3.1 , 3.2 later controls the camera 2.1 , 2.2 , 2.3 in the other direction, thus changing at least one parameter value with the goal of achieving higher image quality through a higher resolution and / or higher frame rate and / or lower compression, even if this requires a higher bandwidth. In this way, each workstation computer 3.1, 3.2 automatically and continuously performs closed-loop control of the bandwidth actually required to transmit the image signals from the connected cameras 2.1, 2.2, 2.3.

[0290] According to the embodiment just described, each workstation computer 3.1, 3.2 causes the value of at least one parameter of the or at least one, preferably each connected camera 2.1, 2.2, 2.3 to be changed with the aim of reducing or increasing the bandwidth, whereby this bandwidth is required to transmit the image signals of all connected cameras 2.1, 2.2, 2.3. In one embodiment, the workstation computer 3.1, 3.2 changes the parameter value by a predetermined or randomly selected absolute or percentage value. In another embodiment, the workstation computer 3.1, 3.2 determines how many people are currently in or at the monitored workstation A.1, A.2 according to the signals from the access control unit 6.1, 6.2. The workstation computer 3.1 , 3.2 changes the parameter value with the following control objective: The larger the number of people detected in or at the workstation A.1 , A.2, the greater the bandwidth available for the transmission of the cameras 2.1, 2.2, 2.3 in or at this workstation A.1, A.2. One reason: the more people there are currently, the more important it is for the operator in a control center Z, T to detect an undesired event quickly and reliably. If, according to the access control unit 6.1, 6.2, there is no one at all in or at the workstation A.1, A.2, the workstation computer 3.1, 3.2 results in a relatively low bandwidth. As already explained, even in this case at least one image signal is transmitted from this workstation A.1, A.2 to the control centers Z, T - among other reasons because there may be a person there who has not logged on.

[0291] In one embodiment, the surveillance system comprises an image evaluation unit. This image evaluation unit is capable of automatically evaluating the image signal from at least one camera 2.1, 2.2, 2.3 and, based on the image evaluation, deciding whether the image signal currently depicts movement or not. Typically, this movement originates from a worker at the monitored workstation A.1, A.2, but it can also originate from a falling object or an object moving in some other way. According to the embodiment with the image evaluation unit, the bandwidth required to transmit the image signal from a camera 2.1, 2.2, 2.3 is then reduced if this image signal shows no movement.

[0292] As already explained, the bandwidth required to transmit the image signal from a camera 2.1, 2.2, 2.3 to the central output computer 20 and to the tablet Tb is reduced. Preferably, the workstation computer 3.1, 3.2 to which this camera 2.1, 2.2, 2.3 is assigned initiates the required bandwidth reduction. As explained above, at least one bandwidth-relevant parameter of the camera 2.1, 2.2, 2.3 is changed to reduce the bandwidth. Reducing the required bandwidth often also results in reduced image quality when displaying the image signal. In a preferred embodiment, the image quality is therefore increased again on a trial basis, even if more bandwidth is required to transmit the image signal after the increase. To increase the image quality, at least one bandwidth-relevant parameter of the camera 2.1, 2.2, 2.3 is changed accordingly. Preferably, the workstation computer 3.1, 3.2 initiates the1 , 3.2 also automatically increases the image quality.

[0293] In one implementation, the step to increase the image quality again is triggered at least when a specified period of time has elapsed since the bandwidth was reduced. Furthermore, it is possible to test the image quality even if the required bandwidth has not been reduced beforehand.

[0294] In one implementation, a workstation 3.1, 3.2 increases the image quality at random times on a trial basis. For example, each workstation 3.1, 3.2 includes a random number generator that generates random times. Or, each workstation 3.1, 3.2 increases the image quality at a predetermined frequency, with each workstation 3.1, 3.2 using a different frequency. Both embodiments reduce the risk of multiple workstations 3.1, 3.2 simultaneously increasing the image quality on a trial basis, resulting in the available bandwidth being insufficient and the bandwidth having to be reduced again, which could lead to instability.

[0295] Preferably, the workstation computer 3.1, 3.2 determines whether sufficient bandwidth is available before and / or after an increase in image quality. If sufficient bandwidth is actually available, the increased image quality is maintained. The camera 2.1, 2.2, 2.3 retains the corresponding values ​​for its bandwidth-relevant parameters. Otherwise, each bandwidth-relevant parameter is assigned its old value, i.e., the value before the increase. Preferably, a value range is specified for each camera 2.1, 2.2, 2.3 and for each bandwidth-relevant parameter of this camera 2.1, 2.2, 2.3. The parameter is only changed within this value range.

[0296] Power supply for the workstation computer As already explained, in one embodiment the workstation computer

[0297] 3.1 , 3.2 not only the internal electrical consumers, but also the or each camera 2.1 , 2.2 , 2.3 and / or the or each gas measuring device 1.1 , 1.2 , 1.3 , 1.4 with electrical energy. It is also possible that at least one camera 2.1 ,

[0298] 2.2, 2.3 and / or a gas measuring device 1.1, 1.2, 1.3, 1.4 includes its own power supply unit.

[0299] In a preferred embodiment, the workstation computer 3.1, 3.2 can be connected to a stationary power supply network and includes, for example, a corresponding cable with a corresponding plug. However, it is often not possible to supply a workstation A.1, A.2 to be monitored with electrical power via a suitable stationary power supply network. In particular, it is often not possible or at least not desirable to install long power cables.

[0300] In one embodiment, the communication unit 10 supplies the or at least one workstation computer 3.1, 3.2 with electrical energy, preferably via a cable. The above-mentioned series connection between the communication unit 10 and at least two workstation computers 3.1, 3.2 also makes it possible to supply energy to the connected workstation computers 3.1, 3.2: The communication unit 10 has its own power supply unit or is connected to a stationary power supply network. The communication unit 10 supplies the first workstation computer 3.1 with electrical energy, preferably via a cable. The first workstation computer 3.1 supplies the second workstation computer 3.2 with electrical energy. It is also possible for the first workstation computer 3.1 to permanently supply the second workstation computer 3.2 with electrical energy, i.e. without the first workstation computer 3.1 is supplied with electrical energy by the communication unit 10. Preferably, each workstation computer 3.1, 3.2 nevertheless has its own power supply unit, which is used in the event that the power supply by the communication unit 10 is interrupted or not possible due to local conditions. For the reasons stated above, the monitoring unit 100.1, 100.2 preferably has its own power supply unit, which supplies at least the workstation computer 3.1, 3.2 with electrical energy, optionally additionally the camera(s) and / or the gas measuring device(s) 1.1, 1.2, 1.3, 1.4. This power supply unit preferably comprises at least one rechargeable battery (accumulator), preferably several accumulators.

[0301] A preferred embodiment of this separate power supply unit is described below.

[0302] The preferred design meets the following limiting conditions:

[0303] - In a potentially explosive atmosphere, a device containing an electrical component must not be unscrewed.

[0304] - A power supply unit should not be charged in a potentially explosive atmosphere. In particular, a charger is often not switched off as an intrinsically safe device.

[0305] - The monitoring of the workstation A.1, A.2 must not be interrupted as long as at least one worker is present there, not even in order to replace a power supply unit of the monitoring unit 100.1, 100.2.

[0306] - A device with its own power supply unit may only be transported by air freight if the power supply unit has a maximum electrical charge of 100 Wh.

[0307] According to the preferred embodiment, the power supply unit for the monitoring unit 100.1, 100.2 comprises an internal power source and at least one external power source, preferably two external power sources. The internal power source is arranged in the housing that also houses the workstation computer 3.1, 3.2. The housing thus protects the internal power source to a certain extent from external damage.

[0308] Figure 4 schematically shows the workstation computer 3.1 of the monitoring unit 100.1 for the workstation A.1. The workstation computer 3.1 comprises - a housing 30,

[0309] - an electrical consumer in the form of a circuit board 34,

[0310] - an internal voltage source 31 and

[0311] - two external voltage sources 32.1 , 32.1 ' and 32.2, 32.2'.

[0312] The three voltage sources 31, 32.1, 32.2 together form the voltage supply unit for the workstation computer 31, optionally for the entire monitoring unit 100.1.

[0313] In one embodiment, the workstation computer 3.1 can also supply the camera 2.1 and the gas measuring devices 1.1, 1.2 with electrical power. The workstation computer 3.2 and the communication unit 10 can each comprise their own power supply unit, which in one embodiment is constructed in the same way as that of the workstation computer 3.1.

[0314] In the implementation shown by way of example in Figure 4, the camera 2.1 is mechanically connected to the workstation computer 3.1, namely detachably, preferably via a coupling point at the top of the housing 30. The lens 9 and the light source 11 of the camera 2.1 are shown by way of example.

[0315] The or each external voltage source 32.1, 32.1', 32.2, 32.2' can be detachably connected to the workstation computer 3.1. The workstation computer 3.1 is capable of determining the current fill level of each connected external voltage source 32.1, 32.1', 32.2, 32.2' and comparing it with at least one predefined lower fill level limit. For example, a first fill level limit is 3% or 5%, and a second fill level limit is 10% of the maximum fill level. Generally, the first fill level limit is less than or equal to the second fill level limit.

[0316] Preferably, the detachable electrical connection between the workstation computer 3.1 and the external voltage source 32.1, 32.1', 32.2, 32.2' is established in one of the following two ways:

[0317] - In one embodiment, at least one coupling point for an external voltage source 32.1', 32.2' is embedded in the housing 30 of the workstation computer 3.1, preferably two coupling points, each for an external voltage source. Because the workstation computer 3.1 is designed to be intrinsically safe, an external voltage source 32.1', 32.2' may be connected to the coupling point and disconnected from the coupling point during operation, even if the workstation computer 3.1, 3.2 is located in a potentially explosive environment.

[0318] - In another embodiment, a trough-shaped receptacle for an external voltage source 32.1, 32.2 is embedded in the housing 30. The receptacle includes the necessary electrical contact points for the voltage source, and a closure can selectively open or close the receptacle. Because the workstation computer 3.1 is designed to be intrinsically safe, the closure may be opened during operation, an external voltage source 32.1, 32.2 removed from the receptacle, a new external voltage source 32.1, 32.2 inserted, and the closure closed again.

[0319] In the example of Figure 4, two receptacles for two external voltage sources 32.1 and 32.2 are embedded in the housing 30. An external voltage source 32.1, 32.2 can be inserted into one of these receptacles and removed again. The two receptacles can each be closed with a closure 33.1, 33.2. Figure 4 also shows two coupling points 35.1, 35.2, to each of which an external voltage source 32.1', 32.2' can be connected, for example, using a suitable connector.

[0320] First, the configuration with a single external voltage source 32.1 is described. The workstation computer 3.1 is supplied with electrical energy by the external voltage source 32.1 until the fill level of the external voltage source 32.1 falls below the predetermined first fill level threshold. When the fill level has fallen below the first fill level threshold, the workstation computer 3.1—more precisely, a signal-processing control unit (not shown) for the workstation computer 3.1—switches the power supply unit so that the workstation computer 3.1 is now supplied by the internal voltage source 31. Furthermore, the workstation computer 3.1 generates a low fill level message. Preferably, the workstation computer 3.1 generates this low fill level message when the measured fill level has fallen below the second fill level threshold but is still above the first fill level threshold.This message is preferably transmitted to the central units Z, T and output in the central units Z, T or another spatially distant receiver in a form perceivable by a human. This message is preferably also output on a screen of the workstation computer 3.1. The workstation computer 3.1 later automatically detects the event that a new external voltage source 32.1 is connected to the workstation computer 3.1. The workstation computer 3.1 then switches back to being supplied by the connected external voltage source 32.1. The time period that elapses until the fill level of the internal voltage source 31 has also fallen below a predetermined fill level threshold is available for the process of replacing the used external voltage source 32.1 with a new external voltage source 32.1.

[0321] The embodiment with a first external voltage source 32.1 and a second external voltage source 32.2 will now be described. As long as the workstation computer 3.1 is connected to two external voltage sources 32.1, 32.2 at the same time, it is initially supplied with electrical energy from the first external voltage source 32.1, and this continues until the fill level of the first external voltage source 32.1 has fallen below the predetermined first fill level threshold. The workstation computer 3.1 then automatically switches to a supply from the second external voltage source 32.2. In addition, the workstation computer 3.1 in turn generates a message concerning the low fill level of the first external voltage source 32.1, and this preferably happens when its fill level has fallen below the second fill level threshold. The workstation computer 3.1 is supplied with electrical energy from the second external voltage source 32.1 until the fill level of the first external voltage source 32.1 has fallen below the predetermined first fill level threshold.2 until the level of the second external voltage source 32.2 falls below the first level threshold. As soon as the level of the second external voltage source 32.2 falls below the first level threshold, the system switches back to supply from the first external voltage source 32.1 - provided the exhausted first external voltage source 32.1 has been replaced by a new external voltage source while the workstation computer 3.1 was supplied from the second external voltage source 32.2. Otherwise, the internal voltage source 31 is used.

[0322] It is possible for workstation computer 3.1 to be supplied from an external voltage source 32.1, 32.2 until its level falls below the first level threshold. It is also possible for workstation computer 3.1 to be supplied preferentially from the first external voltage source 32.1, namely as long as its level remains above the first level threshold. The entire period during which the level of the second external voltage source 32.2 remains above the first level threshold is available for replacing the first external voltage source 32.1.

[0323] At any given time, the workstation computer 3.1 is supplied with electrical energy from exactly one external voltage source 32.1 or 32.2, provided the charge level of this external voltage source 32.1, 32.2 is above the first charge level threshold. The internal voltage source 31 acts as a buffer storage device that supplies the workstation computer 3.1 with electrical energy if and only if no connected external voltage source 32.1, 32.2 has a charge level above the first charge level threshold.

[0324] After use, it is possible to remove the workstation computer 3.1 from the potentially explosive environment and to charge or replace the internal voltage source 31 outside the potentially explosive environment.

[0325] As already explained, the communication unit 10, on the one hand, forwards signals from the or each connected workstation computer 3.1, 3.2 to the central units Z, T and, conversely, forwards messages from the central units Z, T to the or each connected workstation computer 3.1, 3.2. In one embodiment, the communication unit 10 can be connected to a stationary power supply network. Preferably, the communication unit 10 also has its own power supply unit. Particularly preferably, this power supply unit for the communication unit is designed exactly as described above with reference to Figure 4 for the workstation computer 3.1 with the internal power source 31 and the two external power sources 32.1, 32.2.

[0326] Figures 5, 6, and 7 show, by way of example, a configuration that enables the devices of the first central station Z to be transported quickly to a desired location. This configuration, on the one hand, enables the establishment of a radio link between the communication unit 10 and the central output computer 20. On the other hand, it facilitates the installation of the first central station Z at a location where a good connection to a public mobile radio network I, 15 can be achieved.

[0327] To transport the devices of the first control center Z, a two-part and preferably rigid housing 40 is used, comprising a removable housing section 40.1 and a support 40.2. If the two housing sections 40.1, 40.2 are mechanically connected to one another, they enclose a space which, in the exemplary embodiment, is cuboid-shaped. The removable housing section 40.1 can be detachably connected to the support 40.2 using a plurality of snap fasteners 42.1, 42.2, ... on the removable housing section 40.1 and corresponding projections 42.3, 42.4 on the support 40.2. The closed housing 40 can be placed on a trolley 41 and thus moved with relatively little effort. The housing 40 can be detachably connected to the trolley 41 using snap fasteners 43.1, 43.2. The housing 40 preferably comprises handles 44.1, 44.2 on the removable housing part

[0328] 40.1 to transport the housing 40. Figure 5 shows the housing 40, with the removable housing part 40.1 connected to the support 40.2. In Figure 5, on the left, the trolley 41 is shown in front of the housing 40. In Figure 5, on the right, the housing 40 is shown on the trolley 41.

[0329] Figure 6 shows the three screens 22, 23.1, 23.2 on the support 40.2 after the removable housing part 40.1 has been removed. The additional screen 23.1 stands on a stand 45.1, the additional screen 23.2 on a stand

[0330] 45.2. The screen surfaces of the additional screens 23.1, 23.2 face away from the viewer and toward the screen surface of the projecting overview screen 22. A transport support 46 is detachably or permanently connected to the support 40.2 and supports the additional screens 23.1, 23.2 during transport.

[0331] The two additional screens 23.1, 23.2 can be lifted from the support 40.2 and positioned to the left or right of the overview screen 22. In one embodiment, the overview screen 22 is mechanically connected to the support 40.2, so that the support 40.2 also functions as a base for the overview screen 22.

[0332] During transport, the housing 40 preferably also accommodates the central output computer 20, the headphones 21 with the microphone 27, and the communication unit 47. In one embodiment, the devices of the first control center Z are connected to one another in advance by cables and placed on the carrier 40.2 in the cabled state. The removable housing part 40.1 is placed on the carrier 40.2 and connected to the carrier 40.2, thus creating a housing 40, as shown in Figure 5. The housing 40 encloses the cabled devices of the first control center Z. At a location of use, the removable housing part 40.1 is removed from the carrier 40.2. The two additional screens 23.1, 23.2 are positioned next to the overview screen 22, a connection to a stationary power supply network or a dedicated power supply unit is established, and the communication unit 44 is connected to the Internet and in particular to the central computer 15.In many cases, only a few minutes are required to set up the first central Z.

[0333] Structure and function of the headquarters

[0334] As already explained, an operator in a control center Z, T monitors the workstation A.1, A.2. The control center Z comprises a central output computer 20. The central output computer 20 and the tablet Tb can be connected to a stationary power supply network. In one embodiment, the central output computer 20 and the tablet Tb each additionally comprise their own power supply unit or can be connected to such a unit. The separate power supply unit makes it possible to position the central output computer 20 and the tablet Tb close to the workstation or a workstation to be monitored, even if no stationary power supply network is available there. The separate power supply unit can be designed as described above for the workstation computer 3.1 with reference to Figure 4.

[0335] The first control center Z of the exemplary embodiment comprises an overview screen 22 and optionally at least one further screen 23.1, 23.2. The overview screen 22 is preferably larger than the or each further screen 23.1, 23.2. The overview screen 22 has, for example, a diagonal of 43 inches, and the or each further screen 23.1, 23.2 has a diagonal of 24 inches each. In one embodiment, two further screens 23.1, 23.2 are attached laterally and rotatably to the overview screen 22, similar to two wings of an altarpiece (retable) known from a church. It is also possible for the or each further screen 23.1, 23.2 to be set up next to the overview screen 22, in particular with the aid of a respective stand 45.1, 45.2.

[0336] It is possible for the operator to monitor several workstations A.1, A.2 simultaneously in a control center Z, T. In this embodiment, the overview screen 22 or the screen of the tablet Tb is divided into several areas 24.1, 24.2. In each area 24.1, 24.2, image signals from one camera 2.1, 2.2, 2.3 are displayed. The operator can select a displayed area 24.1, 24.2 and thereby a monitored workstation A.1, A.2. The image signals as well as measured values ​​and other information from the selected monitored workstation A.1 are displayed on a further screen 23.1, 23.2. In particular, one signal from each gas measuring device 1.1, 1.2 that is installed at the workstation A.1 is displayed there.

[0337] In one embodiment, the operator can control the or each camera 2.1, 2.2, 2.3 at a monitored workstation A.1, A.2 from the control center Z, T. In particular, the operator can cause one of the following changes to be carried out on the camera 2.1, 2.2, 2.3:

[0338] An optional actuator pivots and / or shifts the camera 2.1, 2.2, 2.3, and in particular changes the viewing direction and / or angle and / or image scale of the camera 2.1, 2.2, 2.3. - The focal length and thus the image scale of the camera 2.1, 2.2, 2.3 are changed. The camera 2.1, 2.2, 2.3 thus zooms in or out of the workstation.

[0339] - An optional light source of camera 2.1, 2.2, 2.3 is switched on or off.

[0340] - The camera 2.1 , 2.2, 2.3 is switched on or off.

[0341] - The resolution and / or frame rate at which the photosensor of camera 2.1, 2.2, 2.3 generates images is changed. This changes the bandwidth required to transmit the image signal from camera 2.1, 2.2, 2.3.

[0342] - A bandwidth-relevant parameter of an algorithm is changed, which the image processing unit of the camera 2.1, 2.2, 2.3 uses to process the images of the photosensor and to generate the image signal of the camera 2.1, 2.2, 2.3 through the processing.

[0343] The operator is notified visually and / or acoustically that one of several possible alarm situations has occurred. Or the operator detects an alarm situation themselves. Examples of alarm situations include:

[0344] - A gas measuring device 1.1, 1.2, 1.3, 1.4 has detected a target gas concentration above a specified concentration limit.

[0345] - The optional image evaluation unit has automatically detected a dangerous situation at the monitored workstation A.1, A.2, for example, a fire or a very rapid movement. Such a movement could be caused by a falling object or a worker falling.

[0346] - A workstation computer 3.1, 3.2 for a monitored workstation A.1, A.2 has detected that it is not receiving an image signal from a camera and / or a signal from a gas measuring device 1.1, 1.2, 1.3, 1.4 and / or from a voice input unit 4.1, 4.2 and / or from an access control unit 6.1, 6.2.

[0347] - The communication unit 10 has detected that it is not receiving a signal from a workstation computer 3.1, 3.2. - The operator has discovered that a dangerous situation at a monitored workstation A.1, A.2, for example an accident or a fire, is being displayed on a screen 22, 23.1, 23.2 in the control center Z, T.

[0348] - The data connection between a monitoring unit 100.1, 100.2 and a central unit Z, T is interrupted.

[0349] - A worker has signaled that an alarm should be triggered at workstation A.1, A.2.

[0350] - The operator has discovered that a worker at workstation A.1, A.2 is not wearing the prescribed protective equipment and / or has not logged in to the access control unit 6.1, 6.2. The first event can often be detected in images from at least one camera 2.1, 2.2, 2.3. The second event can result in more people being visible in an image from workstation A.1, A.2 than are currently in or at workstation A.1, A.2 according to the access control unit 6.1, 6.2.

[0351] As already shown, in one embodiment the overview screen 22 is divided into a plurality of areas 24.1, 24.1, with image signals from a camera 2.1, 2.3 being displayed in each area 24.1, 24.1. If a gas measuring device 1.1, 1.2, 1.3, 1.4 at a workstation A.1, A.2 detects an alarm, each area on the overview screen 22 on which an image signal from this workstation A.1, A.2 is displayed is highlighted. This outputs the alarm visually. For example, a frame 27.1, 27.2 around the area 24.1, 24.2 is displayed differently. In addition, an alarm is preferably output acoustically, for example by an acoustic signal on the operator's headphones 21.

[0352] The example in Figure 3 shows schematically and exemplarily how an alarm situation is presented to the operator in the control center Z:

[0353] - The frame 27.1 surrounding window 24.1 is highlighted. This indicates that an alarm situation has occurred at workstation A.1.

[0354] - An acoustic message is played on the headset 21.

[0355] - On the additional screen 23.1, two windows 25 and 26 are displayed. - Window 26 displays the measured target gas concentrations con.1 and con.2, which the two gas detectors 1.1 and 1.2 measured at workstation A.1. The target gas concentration con.1 is highlighted. This visually indicates that this value is above a concentration threshold and is therefore dangerously high. Based on this measurement, gas detector 1.1 has triggered the alarm for workstation A.1.

[0356] The operator selects the workstation(s) A.1 affected by the alarm situation. For example, if a harmful gas has leaked or a fire has broken out at workstation A.1, then the workstations above and / or adjacent to it are also affected.

[0357] For the or each selected workstation A.1, the operator triggers the step of triggering an alarm at this workstation A.1. Triggering an alarm triggers the following actions, either automatically or after appropriate confirmation by the operator:

[0358] - The alarm element emits a visual and audible alarm. A necessary consequence is that workstation A.1 is evacuated.

[0359] - The access control unit 6.1 informs a worker who wants to log in that workstation A.1 is locked and may not be entered.

[0360] - A message containing the alarm is transmitted to at least one other communication unit, for example to a

[0361] Communication unit of a factory fire brigade or a medical station.

[0362] In the event of an alarm, a notification window also opens on one screen, preferably on another screen (23.1, 23.2). The operator can initiate the actions to respond to the alarm by entering information in this notification window. The notification window displays possible actions that the operator must initiate in many cases, but not in every case. Examples include:

[0363] Workstation A.1 is locked as described above. A paramedic is notified and asked to go to the workstation.

[0364] Figure 3 illustrates this as an example: In window 25, a list is shown. This list shows measures that must be taken after an alarm occurs at workstation A.1. Three measures A, B, C are shown as examples. An input field is shown next to each measure in the list in window 25. In one implementation form, the operator makes an entry in an input field next to a measure A, B, C and thereby triggers this measure A, B, C. In another implementation form, the operator triggers measure A, B, C and then confirms by entering something in the input window that this measure A, B, C has been triggered. In both implementation forms, it is the operator's responsibility to decide which measures they actually trigger. The list in window 25 reduces the risk that the operator will not trigger a required measure A, B, C.On the other hand, a corresponding action A, B, C is only triggered after the operator has released it.

[0365] The operator at a control center Z, T is also informed of events that also require a response, but do not require the immediate interruption of work at a workstation A.1, A.2. Examples of such events are:

[0366] - Only limited bandwidth is available to transmit image signals from workstations A.1, A.2 to a central station Z, T. One possible response, namely turning down the power of one or more cameras 2.1, 2.2, 2.3 at this workstation A.1, A.2, has already been described above. As already explained, this response is triggered automatically. The operator can also initiate this action.

[0367] - The fill level of an external voltage source 32.1, 32.2 for a device in a monitoring unit 100.1, 100.2 has fallen below the specified second fill level threshold. The voltage source 32.1, 32.2 must be replaced.

[0368] Preferably, it is ensured that the operator actually monitors each workstation A.1, A.2. Of course, it can never be ruled out that an operator suffers a fainting spell or an accident and is therefore no longer able to perform the monitoring. Preferably, the central output computer 20 and the tablet Tb therefore check how much time has elapsed since the last user input in the central station Z, T. If the elapsed time is greater than a predetermined first time duration limit, the central output computer 20 and the tablet Tb preferably cause a request to be issued to the operator to make a user input now. If no user input is detected after a further period of a predetermined duration has elapsed, the central output computer 20 and the tablet Tb each generate a corresponding

[0369] Alarm message and cause this alarm message to be transmitted to a remote recipient. This recipient is, for example, a computer of another operator ("field operator"). In one embodiment, a data connection can be established between this computer, which acts as the recipient of the alarm message, and the central computer 15, so that the other operator can also remotely monitor the or each workstation A.1, A.2. Furthermore, the central output computer 20 preferably causes an alarm to be issued at each workstation A.1, A.2.

[0370] List of reference symbols

[0371]

[0372]

[0373]

Claims

Monitoring system for monitoring at least one workstation (A.1, A.2), wherein the monitoring system comprises at least one monitoring unit (100.1, 100.2) for the or each monitored workstation (A.1, A.2), wherein the monitoring system further comprises - a communication unit (10) and - a first central unit (Z, 16), wherein the first central unit (Z, 16) - is spatially removed from the communication unit (10) and the or each monitoring unit (100.1, 100.2) and - a central output computer (20) and an output unit (21, 22, 23.1 , 23.2), wherein the or each monitoring unit (100.1 , 100.2) each - at least one camera (2.1, 2.2, 2.3), - at least one gas measuring device (1 .1 , 1.2, 1.3, 1.4) and - a workstation computer (3.1, 3.2), wherein the or each camera (2.1, 2.2, 2.3) is designed to generate an image signal from the monitored workstation (A.1, A.2), wherein the or each gas measuring device (1.1, 1.2, 1.3, 1.4) is designed to measure a measure of the respective concentration (con.1, con.2) of at least one target gas at the monitored workstation (A.1, A.2), wherein in a first alternative the or each gas measuring device (1.1, 1.2, 1.3, 1.4) and in a second alternative the workstation computer (3.1, 3.2) (100.1, 100.2) of the monitoring unit (100.1, 100.2) of a monitored Workplace (A.1 , A.2) are designed to - to compare a measured target gas concentration (con.1 , con.2) with a given concentration limit and - to generate an alarm when the measured target gas concentration (con.1, con.2) is above the concentration limit, wherein the or each camera (2.1, 2.2, 2.3) and the or each gas measuring device (1.1, 1.2, 1.3, 1.4) of a monitoring unit (100.1, 100.2) are connected or connectable to the workstation computer (3.1, 3.2) of this monitoring unit (100.1, 100.2) in each case by cable and / or wirelessly, in particular by radio waves, wherein the or each workstation computer (3.1, 3.2) is or can be connected to the communication unit (10) by a data connection via cable and / or wirelessly, in particular via radio waves, wherein the communication unit (10) is or can be connected to the central output computer (20) by a data connection, wherein the data connection between the communication unit (10) and the central output computer (20) comprises a wireless data connection, in particular via radio waves, wherein the monitoring system is designed to transmit, for each monitored workstation (A.1, A.2), each image signal and each alarm via the respective workstation computer (3.1, 3.2) and the communication unit (10) to the central output computer (20), and wherein the central output computer (20) is designed to control the output unit (21, 22, 23.1, 23.2) in such a way that the controlled output unit (21, 22, 23.1, 23.2) for each monitored workplace (A.1 , A.2) outputs a representation (A.1 ', A.2') in each case, wherein the representation (A.1 ', A.2') is for a workstation (A.1 , A.2). - in at least one form perceivable by a human, preferably visually, any alarm from this workplace (A.1, A.2) and at any time during monitoring, represents the or each image signal from this workstation (A.1, A.2). Monitoring system according to claim 1, characterized in that the monitoring system comprises a first monitoring unit (100.1) for a first monitored workstation (A.1) and a second monitoring unit (100.2) for a second monitored workstation (A.2), each of these at least two monitoring units (100.1, 100.2) respectively. - at least one camera (2.1, 2.2, 2.3), - at least one gas measuring device (1 .1 , 1.2, 1.3, 1.4) and - comprises a workstation computer (3.1, 3.2), wherein the respective workstation computer (3.1, 3.2) of each of these at least two monitoring units (100.1, 100.2) is connected or connectable to the communication unit (10) by a respective data connection, and wherein the communication unit (10) is preferably arranged outside each monitored workstation (A.1, A.2). Monitoring system according to one of the preceding claims, characterized in that the data connection between the communication unit (10) and the central output computer (20) is routed entirely or at least partially via a public mobile radio network (I, 15), the public mobile radio network (I, 15) uses a central computer (15), and a region (16) of the central computer (15) is permanently or at least temporarily in a data connection with the communication unit (10) and permanently or at least temporarily in a data connection with the central output computer (20), wherein the region (16) of the central computer (15) comprises a processing program (18) which can be executed on the central computer (15), wherein an output program (48) is installed on the central output computer (20), wherein the processing program (18) is designed to generate a processing (17) when it is executed, wherein the processing (17) each monitored workstation (A.1, A.2) - each alarm from the or a gas measuring device (1.1, ..., 1.4) and the respective image signal of the or each camera (2.1, 2.2, 2.3) and - can be displayed in at least one form perceivable by a human, preferably visually, and wherein the central output computer (20) is designed to control the output unit (21, 22, 23.1, 23.2) using the output program (48) in such a way that the display (A.1', A.2') output by the controlled output unit (21, 22, 23.1, 23.2) represents the displayable processing (17). Monitoring system according to claim 3, characterized in that the monitoring system comprises at least a second central unit (T, 16), wherein the second central unit (T, 16) is spatially remote from the first central unit (Z, 16), the communication unit (10), and the or each monitoring unit (100.1, 100.2), and a further central output computer (Tb) and an output unit (21, 28), wherein the area (16) of the central computer (15) is permanently or at least temporarily in a data connection with the further central output computer (Tb), wherein an output program (49) is installed on the further central output computer (Tb), wherein the further central output computer (Tb) is designed to control the output unit (21, 28) of the second central unit (T, 16) using the displayable processing (17) and the output program (49) in such a way that the representation (AT, A.2') which the output unit (21, 28) outputs represents the displayable processing (17). Surveillance system according to one of the preceding claims, characterized in that the transmission of an image signal from the or a camera (2.1, 2.2, 2.3) to the central output computer (20) requires a bandwidth and the or each camera (2.1, 2.2, 2.3) has at least one bandwidth-relevant parameter, that is, a parameter whose value influences the bandwidth required for transmitting the image signal, wherein the monitoring system is designed to automatically control the or at least one camera (2.1, 2.2, 2.3) with the aim of changing the respective value of the or at least one bandwidth-relevant parameter in such a way that the bandwidth required for transmitting the image signal from this camera (2.1, 2.2, 2.3) is changed. Monitoring system according to claim 5, characterized in that the monitoring system is designed to automatically - to determine a measure of the bandwidth currently available for data transmission from the communication unit (10) to the central output computer (20), in particular to detect an indication of insufficient bandwidth, and - depending on the determined available bandwidth, to control the or at least one camera (2.1, 2.2, 2.3) with the aim of changing the value of the or a bandwidth-relevant parameter of the camera (2.1, 2.2, 2.3), in particular with the aim of reducing the bandwidth required for transmission. Monitoring system according to claim 6, characterized in that the or each workstation computer (3.1, 3.2) of a monitoring unit (100.1, 100.2) is designed to automatically - to determine the measure of the currently available bandwidth and - controlling the or each camera (2.1, 2.2, 2.3) of this monitoring unit (100.1, 100.2) depending on the determined bandwidth with the aim of changing the parameter value. Monitoring system according to one of claims 5 to 7, characterized in that at least one monitoring unit (100.1, 100.2) Access control unit (6.1, 6.2) for the monitored workstation (A.1, A.2), wherein the monitoring system is designed to determine, using signals from the access control unit (6.1, 6.2), how many people are currently in or at the workstation (A.1, A.2) which is monitored by the monitoring unit (100.1, 100.2), wherein the monitoring system, preferably the monitoring unit (100.1, 100.2), is designed to control the or at least one camera (2.1, 2.2, 2.3) of this workstation (A.1, A.2) depending on the determined number of people in or at the workstation (A.1, A.2), wherein the aim of the control is to determine the value of the bandwidth-relevant parameter of the camera (2.1, 2.2, 2.3). to change in such a way that - the required bandwidth is lower the smaller the number of people is, - the controlled camera (2.1, 2.2, 2.3) transmits an image signal even if the access control unit (6.1, 6.2) has not detected any person in or at the workstation (A.1, A.2).

9. Monitoring system according to one of the preceding claims, characterized in that the monitoring system is designed to transmit, when the or a monitoring unit (100.1, 100.2) has generated an alarm, both the alarm and a message with the target gas concentration leading to the alarm to the first control center (Z, 16), wherein the monitoring system is preferably designed to transmit the alarm with a higher priority than the message with the target gas concentration. Monitoring system according to one of the preceding claims, characterized in that the output unit (21, 22, 23.1, 23.2) comprises a screen (22), wherein the central output computer (20) is designed to control the output unit (21, 22, 23.1, 23.2) in such a way that the controlled output unit (21, 22, 23.1, 23.2) outputs the representation (A.1', A.2') for the or each monitored workstation (A.1, A.2) in a respective area (24.1, 27.1, 24.2, 27.2) of the screen (22), wherein the representation (A.1 ', A.2') for a workplace (A.1 , A.2) - the respective image signal from the or each camera (2.1, 2.2, 2.3) at this workstation (A.1, A.2) and - visually perceptible information about whether the or at least one gas measuring device (1.1, 1.2, 1.3, 1.4) or the workstation computer (3.1, 3.2) at this workstation (A.1, A.2) generates an alarm or not. Monitoring system according to one of the preceding claims, characterized in that the monitoring system comprises a housing (40), wherein the housing (40) - provides an enclosed space and - is designed to accommodate in the enclosed space at least the central output computer (20) and the or each output unit (22, 23.1, 23.2) of the first control center (Z, 16). Monitoring system according to claim 11, characterized in that the housing (40) comprises a removable housing part (40.1) and a carrier (40.2), wherein the removable housing part (40.1) can be detachably connected to the carrier (40.2), wherein the removable housing part (40.1) and the carrier (40.2) when connected to each other provide the enclosed space and wherein the carrier (40.2) - is connected to a component (22), preferably a screen, of the output unit and - provides a stand for this component (22). Monitoring system according to one of the preceding claims, characterized in that the output unit (21, 22, 23.1, 23.2) of the first control center (Z) has an overview screen (22) and at least one further screen (23.1, 23.2), wherein the central output computer (20) is designed to control the overview screen (22) in such a way that the controlled overview screen (22) for the or each monitored workstation (A.1, A.2) in one area each (24.1, 27.1, 24.2, 27.2) of the overview screen (22) outputs the representation (AT, A.2') for this workstation (A.1, A.2), wherein the central output computer (20) is further designed to control the or at least one further screen (23.1, 23.2) after a selection of a monitored workstation (A.1) or after receiving an alarm from a workstation (A.1) in such a way, that the controlled further screen (23.1, 23.2) outputs the or each target gas concentration (con.1, con.2) measured by the or at least one, preferably by each, gas measuring device (1.1, 1.2) arranged at the selected workstation (A.1) and which has generated the alarm. Monitoring system according to one of the preceding claims, characterized in that the central output computer (20) is designed, after receiving an alarm from a gas measuring device (1.1), to control the output unit (21, 22, 23.1, 23.2) in such a way that the controlled output unit (21, 22, 23.1, 23.2) outputs a list (25) in a form perceivable by a human, wherein the output list (25) - specifies the workstation (A.1 ) to which the alarm refers, and - at least one measure (A, B, C) is specified which is to be carried out as a result of this alarm at the or a monitored workstation (A.1). Monitoring system according to claim 14, characterized in that the output unit (21, 22, 23.1, 23.2) of the first control center (Z) comprises an overview screen (22) and at least one further screen (23.1, 23.2), wherein the central output computer (20) is designed to control the overview screen (22) in such a way that the controlled overview screen (22) for the or each monitored workstation (A.1, A.2) in one area (24.1, 27.1, 24.2, 27.2) of the overview screen (22) outputs the representation (A.1 ', A.2') for this workstation (A.1 , A.2), wherein the central output computer (20) is further designed to, after receiving the alarm - to control the overview screen (22) in such a way that the overview screen (22) displays the display for the workstation (A.1) at which the alarm was generated in the assigned screen area (24.1, 27.1, 24.2, 27.2) in a different way than the display for the or each further workstation (A.2) from which no alarm originates, and - to control the or a further screen (23.1) in such a way that the controlled further screen (23.1) outputs the list (25). Monitoring system according to one of the preceding claims, characterized in that the or at least one workstation computer (3.1, 3.2) - comprises a housing (30) and its own power supply unit (31, 32.1, 32.2) and - comprises at least one electrical consumer (34) and / or is electrically connected or at least temporarily connectable to at least one electrical consumer (1.1, 1.2, 1.3, 2.1, 2.2, 2.3), wherein preferably the or each electrical consumer comprises the camera (2.1, 2.2, 2.3) and / or the gas measuring device (1.1, 1.2, 1.3, 1.4), wherein the voltage supply unit (31, 32.1, 32.1', 32.2, 32.2') comprises an internal voltage source (31) and at least one external voltage source (32.1, 32.1', 32.2, 32.2'), wherein the internal voltage source (31) is arranged inside the housing (30), wherein the or each external voltage source (32.1, 32.1', 32.2, 32.2') is detachably connected to the workstation computer (3.1, 3.2) or can be detachably connected, wherein the workstation computer (3.1, 3.2) is designed to - to supply the or each electrical consumer (34, 1.1, 1.2, 1.3, 2.1, 2.2, 2.3) with electrical energy from the or a connected external voltage source (32.1, 32.1', 32.2, 32.2') as long as the fill level of the external voltage source (32.1, 32.1', 32.2, 32.2') is above a predetermined first fill level barrier, and - to generate a message when the fill level is below the first or below a second predetermined fill level threshold, wherein the second fill level threshold is equal to or greater than the first fill level threshold. Monitoring system according to claim 16, characterized in that the power supply unit (31, 32.1, 32.2) comprises a first external voltage source (32.1, 32.1') ​​and a second external voltage source (32.2, 32.2'), wherein the workstation computer (3.1, 3.2) is configured to - when both external voltage sources (32.1, 32.1', 32.2, 32.2') are connected to the workstation computer (3.1, 3.2) at the same time, to supply the or each consumer (34, 1.1, 1.2, 1.3, 2.1, 2.2, 2.3) with electrical energy from the first external voltage source (3.1) until the fill level of the first external voltage source (32.1, 32.1') ​​is below the fill level barrier, and - subsequently supplying the or each consumer (34, 1.1, 1.2, 1.3, 2.1, 2.2, 2.3) from the second external voltage source (32.2, 32.2'). Monitoring system according to claim 16 or claim 17, characterized in that the workstation computer (3.1, 3.2) is designed to supply the or each consumer (34, 1.1, 1.2, 1.3, 2.1, 2.2, 2.3) from the internal voltage source (31) when the respective fill level of the or each connected external voltage source (32.1, 32.1', 32.2, 32.2') is below the first fill level barrier. Monitoring system according to one of the preceding claims, characterized in that the monitoring system comprises a first monitoring unit (100.1) and a second monitoring unit (100.2), wherein the two workstation computers (3.1, 3.2) of these two monitoring units (100.1, 100.2) and the communication unit (10) are connected or can be connected in series in such a way that - the workstation computer (3.1) of the first monitoring unit (100.1) is connected or connectable to the communication unit (10) by a first data connection and - the workstation computer (3.2) of the second monitoring unit (100.2) is connected or connectable to the workstation computer (3.1) of the first monitoring unit (100.1) by a second data connection. Monitoring system according to one of the preceding claims, characterized in that the central output computer (20) is designed to automatically - to check whether at least one message has arrived at the central output computer (20) from the or each workstation computer (3.1, 3.2) within a predetermined time period, wherein the message is an alarm from the or a gas measuring device (1.1, 1.2, 1.3, 1.4) connected to the workstation computer (3.1, 3.2) and / or the image signal from the or a camera (2.1, 2.2, 2.3) connected to the workstation computer (3.1, 3.2) and / or a message generated by the workstation computer (3.1, 3.2), and - if at the end of the time period no such message has been received from the or a workstation computer (3.1, 3.2), to generate an alarm and output it on the output unit (21, 22, 23.1, 23.2) in a form perceivable by a human, wherein the alarm identifies the workstation (A.1, A.2) to which this workstation computer (3.1, 3.2) is assigned. Monitoring system according to claim 20, characterized in that the central output computer (20) is designed to - to generate a request message for the or each connected workstation (3.1, 3.2) at the beginning of the time period and - to cause the request message to be transmitted to this workstation (3.1, 3.2), the monitoring system is designed to transmit the or each request message to the associated workstation (3.1, 3.2), and the or each workstation (3.1, 3.2) is designed to generate a response message in response to receiving a request message and to arrange for the response message to be transmitted to the central output computer (20). Monitoring system according to one of the preceding claims, characterized in that the or each workstation computer (3.1, 3.2) is designed to automatically - to check whether at least one message from the central output computer (20) has arrived at this workstation computer (3.1, 3.2) within a predetermined period of time, and - if no message has arrived at the workstation computer (3.1, 3.2) within the specified time period, to generate a warning and to output this warning at the monitored workstation (A.1, A.2) in a form perceivable by a human. Monitoring system according to claim 22, characterized in that the central output computer (20) is designed to - to generate a request message for the or each workstation (3.1, 3.2) within the time period and - to ensure that the request message is transmitted to the assigned workstation computer (3.1, 3.2). Monitoring method for monitoring at least one workstation (A.1, A.2) using a monitoring system which comprises a monitoring unit (100.1, 100.2) for the or each monitored workplace (A.1, A.2), wherein the monitoring system further comprises - a communication unit (10) and - a first central unit (Z, 16), wherein the first central unit (Z, 16) - is spatially removed from the communication unit (10) and the or each monitoring unit (100.1, 100.2) and - a central output computer (20) and an output unit (21, 22, 23.1, 23.2), wherein the or each monitoring unit (100.1, 100.2) - at least one camera (2.1, 2.2, 2.3), - at least one gas measuring device (1 .1 , 1.2, 1.3, 1.4) and - a workstation computer (3.1, 3.2), wherein during the monitoring of the or a workstation (A.1, A.2) the steps are carried out that the or each camera (2.1, 2.2, 2.3) generates an image signal from the monitored workstation (A.1, A.2), the or each gas measuring device (1.1, 1.2, 1.3, 1.4) measures a measure of the respective concentration (con.1, con.2) of at least one target gas at the monitored workstation (A.1, A.2), wherein in a first alternative the or each gas measuring device (1.1, 1.2, 1.3, 1.4) and in a second alternative the workstation computer (3.1, 3.2) of the monitoring unit (100.1, 100.2) of a monitored workstation (A.1, A.2) - compares a measured target gas concentration (con.1 , con.2) with a given concentration limit and - when the measured target gas concentration (con.1, con.2) is above the concentration threshold, an alarm is generated, the respective image signal of the or each camera (2.1, 2.2, 2.3) and each alarm from the monitored workstation (A.1, A.2) are transmitted via the workstation computer (3.1, 3.2) of the workstation (A.1, A.2) and the communication unit (10) to the central output computer (20), the central output computer (20) controls the output unit (21, 22, 23.1, 23.2) and the controlled output unit (21, 22, 23.1, 23.2) outputs a display (A.1', A.2') for each monitored workstation (A.1, A.2), wherein the display (AT, A.2') for a workstation (A.1 , A.2) comprises in at least one form perceivable by a human each alarm and the or each image signal from this workstation (A.1 , A.2), wherein the or each image signal from camera (2.1 , 2.2, 2.3) is transmitted to the workstation computer (3.1, 3.2) by means of a data connection by cable and / or wirelessly, in particular by radio waves, wherein in the first alternative each alarm is transmitted from the or a gas measuring device (1.1, 1.2, 1.3, 1.4) to the workstation computer (3.1, 3.2), wherein the or each image signal and each alarm. - is transmitted from the workstation computer (3.1, 3.2) to the communication unit (10) by means of a data connection via cable and / or wirelessly, in particular via radio waves, and - is transmitted from the communication unit (10) to the central output computer (20), wherein the transmission from the communication unit (10) to the central output computer (20) takes place at least over a part of the The transmission path is wireless, in particular by means of radio waves, and wherein the transmission from the communication unit (10) to the central output computer (20) is preferably conducted entirely or at least partially via a public mobile radio network (1, 15). Surveillance method according to claim 24, characterized in that the or each camera (2.1, 2.2, 2.3) has at least one bandwidth-relevant parameter, that is, a parameter whose value influences the bandwidth required for transmitting the image signal from this camera (2.1, 2.2, 2.3) to the central output computer (20), wherein the method further comprises the automatically performed steps of - a measure of the bandwidth currently available for data transmission from the communication unit (10) to the central output computer (20) is determined, and - when it is detected that the available bandwidth is too low, - at least one camera (2.1, 2.2, 2.3) is controlled with the aim of changing the value of a bandwidth-relevant parameter of this camera (2.1, 2.2, 2.3) and, by means of this change, reducing the bandwidth required to transmit the image signal from this camera (2.1, 2.2, 2.3), wherein the steps of determining the measure of the bandwidth and controlling the camera (2.1, 2.2, 2.3) are preferably carried out by the workstation computer (3.1, 3.2) of the workstation (A.1, A.2) which is monitored with the aid of this camera (2.1, 2.2, 2.3). Monitoring method according to claim 25, characterized in that the steps are carried out automatically at least once that - at least one camera (2.1, 2.2, 2.3) is controlled with the aim of changing the value of a bandwidth-relevant parameter of this camera (2.1, 2.2, 2.3) and, by means of the change, of temporarily increasing the image quality of the image signal from this camera (2.1, 2.2, 2.3), - checking whether sufficient bandwidth is available to transmit the image signal with the enlarged image quality to the central output computer (20), - if sufficient bandwidth is available, the changed parameter value is retained and - otherwise the camera (2.1, 2.2, 2.3) is controlled with the aim of changing the value of this or another bandwidth-relevant parameter of this camera (2.1, 2.2, 2.3) and reducing the required bandwidth again by the change, wherein these steps are preferably carried out by the workstation computer (3.1, 3.2) of the workstation (A.1, A.2) which is monitored with the aid of this camera (2.1, 2.2, 2.3).

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