Monitoring device

Abstract

Monitoring device (100) with a safety sensor (1) designed to monitor a protective field, wherein the safety sensor (1) triggers a safety function when it registers an object (15) in the protective field, and with a bridging unit (20) by means of which the safety function of the safety sensor (1) can be bypassed, characterized in that a communication system (2) is provided by means of which communication is carried out between the safety sensor (1) and at least one external unit, that the bridging unit (20) is arranged in the safety sensor (1), and that input information is transmitted to the sensor via the communication system (2), wherein a bridging signal is generated in the bridging unit (20) depending on the input information, by means of which the safety function of the safety sensor (1) is bypassed.

Description

[0001] The invention relates to a monitoring device according to the preamble of claim 1.

[0002] Such monitoring devices are used in the field of safety technology, whereby a safety sensor is generally used to monitor the danger zone of a hazardous system, whereby the term system generally also includes machines, robots and the like.

[0003] In particular, the monitoring device is used as access control to a hazardous area of ​​a plant, with access to the hazardous area being via a conveying device.

[0004] The monitoring device typically uses a light curtain as a safety sensor to monitor a protective field lying in a plane. The light curtain generates a switching signal, the switching states of which indicate whether an object is present in the protective field or not. If the light curtain detects an object in the protective field, the corresponding switching signal triggers a safety function. For example, the switching signal activates a control unit of the system, thereby shutting it down so that no further hazards can emanate from the system.

[0005] The conveyor system also generally feeds permissible objects, such as palletized goods, into the system, as required for carrying out the system's operations. Since such permissible objects are not safety-critical, triggering the safety function when these objects move through the protective field of the light curtain would lead to an unnecessary machine shutdown.

[0006] To prevent this, known monitoring devices incorporate muting sensors upstream of the safety sensor in the conveying direction. If the muting sensors detect an object as permissible, the safety sensor is bypassed for a period of time dependent on the object's size, so that it no longer triggers the safety function when the permissible object passes through the protective field.

[0007] Such muting sensors are typically formed from light barrier arrangements. Permissible objects often cannot be reliably detected with such light barrier arrangements.

[0008] Furthermore, a disadvantage is that the coordination of the timing and the evaluation of the signals from the muting sensors is complex and prone to errors, since the time interval until the permissible object has actually passed the safety sensor has to be extrapolated from the times of the object detections of the muting sensors.

[0009] The invention is based on the objective of providing a monitoring device of the type mentioned above, which has a high level of functionality despite its simple design.

[0010] The features of claim 1 are provided to solve this problem. Advantageous embodiments and expedient further developments of the invention are described in the dependent claims.

[0011] The invention relates to a monitoring device with a safety sensor designed to monitor a protective field. The safety sensor triggers a safety function when it detects an object within the protective field. This safety function can be bypassed by a bridging unit. A communication system is provided for communication between the safety sensor and at least one external unit. The bridging unit is located within the safety sensor. The communication system transmits input information to the sensor, and a bridging signal is generated in the bridging unit based on this input information. This bridging signal overrides the safety function of the safety sensor.

[0012] The monitoring device according to the invention is used in the field of security technology, in particular in the field of personal protection.

[0013] The monitoring device includes a safety sensor, i.e., a sensor with a fail-safe design, ensuring compliance with relevant safety engineering standards. For example, the safety sensor incorporates an evaluation unit with a multi-channel computer architecture for processing the sensor signals.

[0014] The safety sensor monitors a protective field. In normal operation, when the safety sensor detects an object intrusion within the protective field, it generates a switching signal as an output signal, which triggers a safety function, for example, shutting down a system monitored by the safety sensor.

[0015] To avoid unnecessary shutdowns of the system, a bypass unit is provided in the safety sensor, which allows the safety sensor to be muted, i.e., the safety function is bypassed, so that an object intrusion into the protective field does not lead to the generation of the switching signal that triggers the safety function.

[0016] This muting mode is activated when a permitted object, i.e., a non-safety-critical object, passes through the protected area. The permitted object could, for example, be a pallet containing material required by the system for processing operations.

[0017] The monitoring device according to the invention has a communication system with which the safety sensor is connected to at least one external unit.

[0018] It is advantageous to have a secure communication system that ensures error-free data transmission.

[0019] Data transmission can be made error-free through the use of checksums and similar safeguards. Additionally, the input and output structures of the communication system can be tested by sending and receiving test signals.

[0020] For example, the communication system is an IO-Link-Safety, a ProfiSafe or an FSOE (FailSafe over EtherCAT).

[0021] A key advantage of the communication system is that it can transmit not only general binary or analog signals, which may include, for example, parameterization signals for the safety sensor or status signals of the safety sensor.

[0022] Rather, according to the invention, input information is also transmitted to the safety sensor via the communication system, whereby a bridging signal is generated in the bridging unit depending on this input information, with which the safety sensor is muted, i.e., the triggering of the safety function of the safety sensor is bridged, i.e., silenced.

[0023] This means that no additional connecting cables are required at the sensor to perform the muting.

[0024] Another advantage is that the input information allows for muting precisely tailored to each permissible object. This ensures that even with changing boundary conditions, such as the speed at which a permissible object enters the protected area, the muting duration can be precisely defined. This guarantees that the safety function is only overridden when a permissible object, and not another safety-critical object, is present in the protected area. Furthermore, the input information allows for flexible and precise adjustment of the muting operation to different objects that may vary in shape, size, and position.

[0025] This ensures that a faulty muting operation, which could lead to dangerous situations, can be avoided with a high degree of certainty.

[0026] Muting can bypass the entire shielded area. Alternatively, partial muting is also possible.

[0027] Partial muting means that only the part of the protected area containing the permitted object is muted. The remaining part of the protected area is not muted, so any object interference within this part of the protected area will trigger the safety function.

[0028] This expands the functionality of the muting operation and, in particular, optimally adapts it to the size of a permissible object that passes through the protected field.

[0029] According to an advantageous embodiment, different input information is transmitted to the safety sensor via the communication system, whereby the bridging signal is generated in the bridging unit depending on this input information.

[0030] The input information can be security-related and / or non-security-related information.

[0031] By transmitting multiple input pieces of information to the safety sensor and contributing to the generation of the bridging signal, the bridging function, i.e., the muting operation, can be precisely adapted to the respective application conditions, especially to permissible objects that should pass through the protective field without triggering the safety function.

[0032] This functionality can be further improved by combining input information transmitted via the communication system and sensor information stored in the sensor in the bridging unit to generate the bridging signal.

[0033] Particularly advantageous is the storage of object information of a permissible object as sensor information in the safety sensor or its transmission as input information to the safety sensor.

[0034] It is of course also possible to transmit some of the object information to the safety sensor via the communication system and to store further object information as sensor information in the safety sensor.

[0035] This object information can include sizes, geometries, gap structures, and positions of permissible objects.

[0036] Furthermore, object information can include speeds and / or dwell times within the protected area.

[0037] Based on this comprehensive object information, the generation of the bypass signal, and thus the activation of the muting mode, can be precisely tailored to permissible objects that are intended to pass through the safety sensor's protective field without triggering the safety function. In particular, it is possible to adapt the muting mode to different permissible objects that pass through the safety sensor's protective field at different times.

[0038] To ensure the most error-free operation of the safety sensor, and in particular error-free muting operation, it is necessary that the muting operation is activated by the bridging signal precisely when a permissible object is located in the protected field.

[0039] This requirement is met by forming capture information from temporal correlations of the input information in the safety sensor and object movements.

[0040] This establishes a defined temporal relationship between the input information received by the safety sensor and the movement of a permitted object. As a result, the safety sensor, upon receiving this input information, possesses precise timing data, allowing it to determine when a permitted object enters and leaves the protected area, based on the time of receipt. This enables the muting duration to be precisely adjusted to the movement of a permitted object.

[0041] Furthermore, it is possible that input information is formed from minimum and / or maximum time windows between the receipt of the input information in the safety sensor and the entry and / or exit of a permissible object from or into the protected field.

[0042] This information also defines temporal correlations between the receipt of input information and the object movements contained therein.

[0043] In addition to the aforementioned object information and time correlations, the input information can also include further information.

[0044] For example, input information is formed from a restart signal or acknowledgment of faults.

[0045] According to an advantageous embodiment, the safety sensor is an optical sensor.

[0046] In particular, the optical sensor forming the safety sensor is a light curtain, an area distance sensor, or a camera sensor.

[0047] According to an advantageous embodiment of the invention, bridging signals or related information are output from the safety sensor to the external unit.

[0048] This is particularly advantageous when the monitoring device has several safety sensors, especially several light curtains, forming a multiple arrangement by means of which several protective fields can be monitored. In this case, bridging signals sent by the first safety sensor to the other safety sensors can be used to coordinate the muting operation of the individual safety sensors.

[0049] In the monitoring device according to the invention, the safety sensor can be connected to different external units via the communication system.

[0050] The first external units can be a control unit, an array of muting sensors and / or a fieldbus system.

[0051] According to one initial variant, only one external unit is directly connected to the safety sensor via the communication system.

[0052] According to a second variant, at least one further external unit is present, which is connected to the communication system and to which at least one first unit is connected, so that the first external unit is connected to the communication system via the further external unit.

[0053] In particular, the additional external unit can be a computer unit, a communication master, a controller (PLC) or a communication gateway to their communication systems / levels.

[0054] Furthermore, the additional external unit can be an electronic module consisting only of a circuit board and electronic components arranged on it.

[0055] According to another variant, the additional external unit is connected to a human-machine interface (HMI).

[0056] Then an operator can specify input information or change it if necessary.

[0057] The invention will be explained below with reference to the drawings. The drawings show: Fig. 1: First embodiment of the monitoring device according to the invention. Fig. 2: First example of a safety sensor for the monitoring device according to the invention. Fig. 3: Second example of a safety sensor for the monitoring device according to the invention. Fig. 4: Third example of a safety sensor for the monitoring device according to the invention. Fig. 5: Second embodiment of the monitoring device according to the invention. Fig. 6: Third embodiment of the monitoring device according to the invention. Fig. 7: Application example for the monitoring device according to the invention a) with a valid object in a first position. b) with a permissible object in a second position.

[0058] Fig. Figure 1 schematically shows an embodiment of the monitoring device 100 according to the invention.

[0059] The monitoring device 100 includes a security sensor 1 which is connected to an external unit 3 via a communication system 2.

[0060] Safety sensor 1 is designed to perform protective field monitoring. In particular, safety sensor 1 monitors a protective field to safeguard a hazardous area at a plant.

[0061] The monitoring device 100 has the advantage of a secure communication system 2, which enables fail-safe data transmission.

[0062] In particular, the communication system 2 is an IO-Link-Safety, a ProfiSafe or an FSOE (FailSafe over EtherCAT).

[0063] In this case, the external unit is formed by a control unit 3, which is formed, for example, by the safety controller that controls the plant.

[0064] The Fig. Figures 2 to 4 show different examples of the safety sensor 1 of the monitoring device 100.

[0065] Fig. Figure 2 schematically shows the sensor components of a light curtain 4. The light curtain 4 comprises a series of light beams 5 emitting transmitters 6 in a first housing 4a and a series of light beams 5 receiving receivers 7 in a second housing 4b. The housings 4a and 4b are arranged at opposite edges of a monitoring area. The light beams 5 monitor a planar protective field. When the protective field is clear, the light beams 5 from the transmitters 6 strike an assigned receiver 7, as shown in Figure 2. Fig. Figure 2 shows that if an object is disturbed within the protective field, the light rays 5 of at least one transmitter 6 are interrupted.

[0066] The light curtain 4 can also be designed as a reflective light curtain. In this case, all transmitters 6 and receivers 7 are housed in a common enclosure 4a, 4b, wherein this enclosure 4a, 4b is arranged at one edge of the monitoring area and a reflector is arranged at the opposite edge of the monitoring area.

[0067] Fig. Figure 3 shows the sensor components of a safety sensor 1 in the form of an area distance sensor 8. The area distance sensor 8 has a distance sensor with a transmitting element 10 that emits light beams 9 and a receiving element 12 that receives light beams 11. The distance sensor is located in a rotating measuring head 13, which is rotatably mounted on a base 14 about a rotational axis D. The rotation of the measuring head 13 periodically guides the transmitted light beams 9 within an area of ​​monitoring. The distance sensor determines the distance to objects 15 within the monitoring area, whereby the distance measurement can be performed using a pulse-time-of-flight method or a phase-measurement method. A protective field is stored in the area distance sensor, which is monitored for object intrusions.

[0068] Alternatively, the area distance sensor 8 can have a stationary distance sensor integrated in a housing 4a, 4b. In this case, the transmitted light beams 9 are periodically guided in the monitored area by means of a deflection unit.

[0069] Fig. Figure 4 shows a security sensor 1 in the form of a camera sensor. This security sensor 1 has an illumination unit 16 as its transmitter unit and an image sensor 17 as its receiver unit, which has a matrix-shaped arrangement of receiving elements. In particular, the image sensor 17 can be formed by a CCD or CMOS array. The camera sensor can be configured as a 3D camera. In this case, distance measurements are performed for all receiving elements using a pulse-time method.

[0070] In general, the safety sensor 1 has an evaluation unit for evaluating the sensor signals generated by the sensor components. To meet the normative requirements for replacement in the field of safety technology, the evaluation unit has a fail-safe, multi-channel design. In particular, the evaluation unit has two mutually monitoring processors.

[0071] The functionality of the monitoring device 100 is explained using the application example according to the Fig. 7a, Fig. 7b explained.

[0072] There is an access point to a danger zone at a facility in the form of a conveying unit 18.

[0073] In this case, access to the danger zone is monitored by a safety sensor 1 in the form of a light curtain 4, whose housings 4a, 4b are oriented in a vertical direction.

[0074] In normal operation, safety sensor 1 generates a switching signal upon detection of an object, triggering a safety function. Specifically, the switching signal is output to the safety controller that manages the system, causing it to shut down as a safety function.

[0075] As the Fig. 7a, Fig. Figure 7b shows that 18 pallets 19 are transported on the conveyor unit in a conveying direction F. These pallets 19 constitute permissible objects 15, i.e., non-safety-critical objects 15. Therefore, they should be able to pass through the protective field of the safety sensor 1 without the safety sensor 1 triggering the safety function.

[0076] For this purpose, a bridging unit 20 is integrated into the safety sensor 1, as shown. Fig. 1 and also the Fig. 5 and Fig. Show 6.

[0077] In the bridging unit 20, a bridging signal is generated, which activates a muting mode in which the protective field of the safety sensor 1 is completely or partially muted, so that an object entering the field does not trigger the switching signal that would activate the safety function. The muted area of ​​the protective field is adapted to the respective permissible object 15 such that, when passing through the protective field, the object lies entirely within the muted area.

[0078] According to the invention, input information is sent to the safety sensor 1 via the communication system 2, depending on which the bridging unit 20 generates the bridging signal.

[0079] Advantageously, different input information is transmitted via the communication system 2 to the safety sensor 1, whereby the bridging signal is generated in the bridging unit 20 depending on this input information.

[0080] The input information can be security-related and / or non-security-related information.

[0081] Security-related information includes: - Object velocity - Time until the object enters the monitored area - Expected duration of the object's stay in the monitored area - Object dimensions (height / length) - Object with stepped contour (height) - Any gaps in the object (the light path of individual rays is briefly cleared again when passing through the object) - Object type, for predefined objects stored in the sensor

[0082] Non-security-related or individual pieces of information with a lower security level are: - Input signals from 2 or 4 muting sensors (the temporal correlation of the signals creates a safety-oriented expectation) - Signals from the conveyor control system. A safety-oriented expectation is built from a non-safety-based signal (object movement) from the conveyor control system, together with internal object detection by the sensor and a temporal expectation.

[0083] According to an advantageous further development, input information transmitted via the communication system 2 and sensor information stored in the sensor are combined in the bridging unit 20 to generate the bridging signal.

[0084] In particular, object information of a permissible object 15 is stored as sensor information in the safety sensor 1 and / or is transmitted as input information to the safety sensor 1.

[0085] Object information can include sizes, geometries, gap structures and positions of permissible objects.

[0086] Furthermore, object information can include speeds and / or dwell times within the protected area.

[0087] With this object information, the size of the muted area of ​​the protective field and also the duration of the muting operation can be precisely adjusted to the objects passing through the protective field 15.

[0088] In particular, precise timing of the muting operation can be carried out such that the muting operation is only activated when the permissible object 15 is located in the protected field.

[0089] Advantageous for this purpose are the acquisition of temporal correlations of the input information in the safety sensor 1 and object movements.

[0090] Furthermore, it is possible that input information is formed from minimum and / or maximum time windows between the input of the input information in the safety sensor 1 and the entry and / or exit of a permissible object 15 from or into the protected field.

[0091] The input information can generally be in the form of binary or analog signals. The input signals can also consist of signals that are unrelated to the muting of safety sensor 1.

[0092] For example, input information is formed from a restart signal or acknowledgment of faults.

[0093] It is also possible that bridging signals or related information are output from safety sensor 1 to the external unit.

[0094] This is particularly advantageous for monitoring devices 100 with multiple safety sensors 1, which can exchange muting information in this way.

[0095] Fig. Figure 5 shows a further embodiment of the monitoring device 100 according to the invention.

[0096] This monitoring device 100 includes several first external units in the form of a fieldbus system 21, an arrangement of muting sensors 22 and a control unit 3.

[0097] The muting sensors detect permissible objects 15 before they enter the protective field of the safety sensor 1. Input information from more distant units can be read via the fieldbus system 21.

[0098] These first external units are connected to another external unit, which may be a computer unit 23 or the like.

[0099] Signals from the first external units are transmitted by the computer unit 23 to the safety sensor 1 as input information via the communication system 2. Alternatively or additionally, signals from the first external units are processed into input information in the computer unit 23 and then sent to the safety sensor 1 via the communication system 2.

[0100] Fig. Figure 6 shows a further embodiment of the monitoring device 100 according to the invention.

[0101] In this case, an electronic module 24 is connected to the safety sensor 1 via the communication system 2. In its simplest form, the electronic module 24 consists only of a circuit board with electronic components mounted on it.

[0102] An HMI 25, i.e. a human-machine interface, is connected to the electronics module 24.

[0103] The HMI 25 can be operated by one person, in particular to output and input information, especially for generating, changing and controlling input information.

[0104] The HMI 25 can, in particular, establish a connection to an end device such as a smartphone or tablet. This allows, for example, connected sensors, such as muting sensors, to be parameterized.

[0105] It is also possible to output status or error messages via the HMI 25.

[0106] The HMI 25 can feature a display for showing menus with device selection of connected devices, error messages, and configuration parameters. The HMI 25 can also include a keyboard.

[0107] The HMI 25 and the communication to the electronic module 24 are advantageously designed to be fault-safe. Reference symbol list 1 safety sensor 2 Communication system 3 Control unit 4 Light curtain 4a first housing 4b second case 5 light beam 6 channels 7 recipients 8 Area distance sensor 9 transmitted light beam 10 transmitting element 11 Receiving light beam 12 Receiving element 13 Measuring head 14 sockets 15 objects 16 lighting units 17 Image sensor 18 conveying units 19 pallets 20 bridging units 21 Fieldbus system 22 Muting processor 23 computer unit 24 Electronic module 25 HMI (Human-Machine Interface) 100 monitoring device D axis of rotation F Funding facility

Claims

[1] Monitoring device (100) with a safety sensor (1) designed to monitor a protective field, wherein the safety sensor (1) triggers a safety function when it detects an object (15) in the protective field, and with a bridging unit (20) by means of which the safety function of the safety sensor (1) can be bypassed, characterized by , that a communication system (2) is provided by means of which communication is carried out between the safety sensor (1) and at least one external unit, that the bridging unit (20) is arranged in the safety sensor (1), and that input information is transmitted to the sensor via the communication system (2), wherein a bridging signal is generated in the bridging unit (20) depending on the input information, by means of which the safety function of the safety sensor (1) is bridged. [2] Monitoring device (100) according to claim 1, characterized by , that a secure communication system (2) is available, through which fail-safe data transmission takes place. [3] Monitoring device (100) according to one of claims 1 or 2, characterized by , that the communication system (2) is an IO-Link-Safety, a ProfiSafe or an FSOE (FailSafe over EtherCAT). [4] Monitoring device (100) according to one of claims 1 to 3, characterized by , that a bridging signal is activated when a permissible object (15) is located in the protective field. [5] Monitoring device (100) according to claim 4, characterized by , that in the case of a permissible object (15) located in the protective field, the protective field is completely or partially bridged. [6] Monitoring device (100) according to any one of claims 1 to 5, characterized by, that different input information is transmitted via the communication system (2) to the safety sensor (1), whereby the bridging signal is generated in the bridging unit (20) depending on this input information. [7] Monitoring device (100) according to claim 6, characterized by that the input information is security-related and / or non-security-related information. [8] Monitoring device (100) according to any one of claims 1 to 7, characterized by , that input information transmitted via the communication system (2) and sensor information stored in the sensor are combined in the bridging unit (20) to generate the bridging signal. [9] Monitoring device (100) according to any one of claims 4 to 8, characterized by, that object information of a permissible object (15) is stored as sensor information in the safety sensor (1) or is transmitted as input information to the safety sensor (1). [10] Monitoring device (100) according to claim 9, characterized by , that object information consists of sizes, geometries, gap structures and positions of permissible objects (15). [11] Monitoring device (100) according to one of claims 9 or 10, characterized by that object information includes velocities and / or dwell times within the protected field. [12] Monitoring device (100) according to any one of claims 1 to 11, characterized by , that capture information is formed from temporal correlations of the input of the input information in the security sensor (1) and object movements. [13] Monitoring device (100) according to any one of claims 1 to 12, characterized by, that input information is formed from minimum and / or maximum time windows between the input of the input information in the safety sensor (1) and the entry and / or exit of a permissible object (15) from or into the protected field. [14] Monitoring device (100) according to any one of claims 1 to 13, characterized by that input information is formed from a restart signal or from acknowledgments of faults. [15] Monitoring device (100) according to any one of claims 1 to 14, characterized by , that the safety sensor (1) is an optical sensor. [16] Monitoring device (100) according to claim 15, characterized by that the optical sensor forming the safety sensor (1) is a light curtain (4), an area distance sensor (8) or a camera sensor. [17] Monitoring device (100) according to any one of claims 1 to 16, characterized by, that bridging signals or related information are output from the safety sensor (1) to the external unit. [18] Monitoring device (100) according to any one of claims 1 to 17, characterized by , that the first external units are a control unit (3), an arrangement of muting sensors and / or a fieldbus system (21). [19] Monitoring device (100) according to claim 18, characterized by , that only a first external unit is directly connected to the safety sensor (1) via the communication system (2). [20] Monitoring device (100) according to claim 18, characterized by , that at least one further external unit is available which is connected to the communication system (2) and to which at least one first unit is connected, such that the first external unit is connected to the communication system (2) via the further external unit. [21] Monitoring device (100) according to claim 20, characterized by , that the other external unit is a computing unit (23). [22] Monitoring device (100) according to claim 20, characterized by , that the further external unit is an electronic module (24) consisting only of a circuit board and electronic components arranged on it. [23] Monitoring device (100) according to one of claims 21 or 22, characterized by that the additional external unit is connected to a human-machine interface (HMI).

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