Optical monitoring system for optical display elements

Abstract

A monitoring system for an optical display element of an emergency stop switch, the monitoring system comprising an operating element with an optical display element, an optical sensor and a safety electronic device, the safety electronic device being connected to the optical display element and the optical sensor, the safety electronic device comprising a safety output and a safety input, being connected to the optical display element via the safety output and to the optical sensor via the safety input, it can thus be ensured that the optical display element is functioning reliably or is not defective in order to avoid consequences that are fatal to life and limb, the optical display element may comprise one or more display elements.

Description

Technical Field

[0001] [Cross-reference to Related Applications] This application claims priority to German Application No. 102021114870, filed on Jun. 9, 2021, the entire content of which is incorporated herein by reference.

[0002] The invention of this application relates to the field of control technology or safety technology.

Background Art

[0003] The so-called "emergency stop switch" serves to reliably protect people from injury and machines, systems or vehicles from damage. In German usage, the term "Not-Aus" often has two functions, namely, emergency-shut-off [=switch off, cut off the energy supply, cut off the power of the connected machine drive] and emergency-stop [=stop, shut down movable machine parts while the power of the connected machine drive is maintained]. The German "Not-Aus" is used as the equivalent word for the English word "emergency switching off". However, then and now, in the normal German usage (German standard edition), the expression "Not-Aus" has also been wrongly reproduced as the English word "emergency stop". To date, for example, in the German version of DIN EN 60947-5-5, the word "Not-Aus" has been wrongly used for the English word "emergency stop" (it should actually be expressed as "Not-Halt").

[0004] Machine malfunctions can lead to risks to people. To ensure that the machine in question can be stopped immediately and at any time when the risk is directly imminent or approaching, the Machine Directive 2006 / 42 / EC of the European Parliament and of the Council stipulates that each machine must be equipped with one or more emergency stop switches. Furthermore, this machine directive imposes design requirements on these components. One requirement is that the emergency stop switch must have control components that are clearly recognizable, easily visible, and readily accessible. For example, in the case of an active emergency stop switch with an additional display element such as an LED (Light Emitting Diode), the function of the switch is visually indicated. If the emergency stop switch is installed in a detachable, wireless, or mobile operating station, the DIN EN ISO 13850 standard specifically requires measures to avoid confusion between active [i.e., illuminated] and inactive [i.e., non-illuminated] emergency stop switches.

[0005] German Patent Application Publication No. 19919012 teaches a method for identifying an activated, separable emergency shut-off command device. The method is characterized by adding an additional device to the emergency shut-off command device to make the emergency shut-off command device one or more specific colors only when the emergency shut-off command device is properly connected in some way to a system and / or machine and is connected to a power source (voltage). As a result, a visual signal is generated indicating that the emergency shut-off command device is ready for operation.

[0006] International Publication 2017 / 139817 discloses a control system for electrically controlled systems. The control system comprises at least one portable, mobile, handheld operating device for displaying information and for an operator to input control commands. The handheld operating device has at least one manually operable safety switch element, to which a lighting device is assigned. The control system comprises a lighting control device designed to electrically and / or electronically control the visually perceptible luminous intensity of the lighting device.

[0007] Therefore, emergency stop switches equipped with indicator elements are known. Figure 1 shows a further example of an emergency stop switch. The emergency stop switch comprises two switches S1 and S2 that can be operated from an operated position to a non-operated position via an operating element 5. The two switches S1 and S2 are connected to safety electronics. An optical indicator element LM (usually an LED) is provided within the operating element 5, and the optical indicator element LM is driven by two channels and monitored while being dynamically controlled by two-channel voltage feedback. The optical indicator element LM may comprise one or more indicator elements. Monitoring is performed by a first probe M1 and a second probe M2. The first probe M1 measures the current of the optical indicator element LM. The second probe M2 measures the voltage of the optical indicator element LM. Thus, the safety electronics SE monitors the function of the optical indicator element LM by driving it with current or voltage and measuring the current or voltage with the first probe M1 or the second probe M2. If a discrepancy occurs between the drive and measurement, the safety electronic device SE will conclude that the emergency stop switch has malfunctioned.

[0008] However, this type of monitoring inherently carries risks regarding a reliable statement of the function of the optical display element (LM). For example, it is known that if an optical display element such as an LED becomes defective due to various factors, current or voltage can be determined via feedback or feedback signals even though the LED does not emit an optical signal.

[0009] This significantly impacts the level of safety required for the application, because the requirements from the risk assessment for current risks lead to specific requirements regarding the level of safety. Standards provide designations for levels of safety, such as "performance level" PL a to e, or "safety integrity level" SIL1 to SIL3. Based on these safety designations and associated levels, misrepresentation of the function of the optical display element LM can lead to safety-related difficulties. Misrepresentation of the function of the optical display element LM would prevent the meeting of the high requirements for the implementation of a mobile emergency stop system.

[0010] In particular, this type of monitoring poses a high risk in the case of emergency stop switches in mobile emergency stop systems. Such mobile emergency stop systems are quite rare and must meet particularly high safety requirements. In addition to having higher safety requirements than fixed emergency stop systems, mobile emergency stop systems must also meet particularly high standards and guidelines according to appropriate and well-known standards. In this case, the reliable functionality of the optical display element is a particularly important safety feature. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] German Patent Application Publication No. 19919012 [Patent Document 2] International Publication No. 2017 / 139817 [Overview of the project]

[0012] This application discloses a monitoring system for an optical display element of an emergency stop switch, the monitoring system comprising an operating element having an optical display element and an optical sensor. The safety electronic device is connected to the optical display element and the optical sensor. Therefore, it is possible to ensure that the optical display element is functioning reliably or not malfunctioning in order to avoid fatal consequences to human life and limbs. The optical display element LM may comprise one or more display elements.

[0013] Depending on the configuration, the safety electronic device includes a safe output and a safe input, and is connected to an optical display element via the safe output. The optical sensor is connected via the safe input. Therefore, the optical display element and the optical sensor are mechanically and electrically connected to the safety electronic device so that the safe input detects the switch process whenever the safe output switches.

[0014] Therefore, a safe output section means that, despite a fault on the output side, it can still be safely switched off and the fault on the output side can be reliably detected. This could be, for example, if one channel of a safety electronic device has a fault (from low impedance to high impedance) and can no longer be switched. This type of fault is clearly detected by the feedback signal. Nevertheless, it can still be safely switched off by the other channels. Similarly, a safe input section means that the inputs can still be read and a fault in the safety input section can be reliably detected. A fault may be understood as, for example, the absence of a feedback signal in the safety electronic device through at least one channel. In this case, a fault in one of the safety input sections of the safety electronic device is detected by a deviation in the feedback signal between the two channels, and the safety input section is continuously confirmed by interrupting and measuring the signal and comparing [dynamization] to detect the fault.

[0015] Depending on the configuration, the monitoring system may further include an optical fiber cable that guides the optical signals from the optical display element to the optical sensor. As a result, the constraint of a specific distance between the optical display element and the optical sensor can be eliminated.

[0016] In further embodiments, the optical sensor comprises at least one of a photoresistor, a photodiode, and a phototransistor. Thus, the optical sensor can be optimally adapted for individual applications.

[0017] In further embodiments, an optical display element may comprise multiple display elements, and an optical sensor may comprise multiple optical sensors. Therefore, the number of optical display elements and optical sensors is not limited. The number of optical sensors or optical display elements depends on the safety requirements and potential risks in the system being monitored [installation, machinery, motor, etc.]. Risk assessment determines the required PL (performance level) or SIL (safety integrity level). These are determined by the structure of the safety electronic device, the reliability of its components, fault detection, etc.

[0018] In a further embodiment, the safety output section comprises at least one first output contact and at least one second output contact. The safety input section comprises at least one first input contact and at least one second input contact. As a result, it becomes possible to connect multiple components to the safety electronic device.

[0019] The present invention discloses a method for a monitoring system for an optical display element of an emergency stop switch. The method comprises generating an optical signal by supplying current or voltage to the optical display element via a safety electronic device. The method further comprises measuring the optical signal via an optical sensor using the safety electronic device. In this case, the optical signal of the emitted optical display element is measured. The method further comprises interrupting the generation of the optical signal for a period of time and measuring the interruption of the optical signal via an optical sensor using the safety electronic device. This step may or may be repeated to enhance the safety of the system. The method further comprises comparing the generated optical signal with the measured optical signal when current or voltage is applied by the safety electronic device. Based on the comparison, conclusions are drawn about the functionality of the optical display element and, consequently, the system. The method further comprises comparing the generated optical signal with the measured optical signal when current is applied and outputting a warning signal if there is a deviation.

[0020] This method ensures that the optical display element LM is illuminated or activated when it should be illuminated. In return, this method ensures that the optical display element LM is not illuminated when it should not be illuminated or is not activated. If a deviation occurs while comparing the generated optical signal with the measured optical signal, the optical display element LM can no longer be relied upon as a source of information regarding the operating status of the system. As a result, the system's emergency stop function can no longer be relied upon, leading to a wide variety of consequences. These consequences can range from, for example, the output of an alarm to a complete shutdown of the system. For example, but not limited to, if the safety electronic device SE detects a failure in the display element LM, the emergency stop function of the actual emergency stop switch will be triggered, and therefore, this mobile emergency stop system can no longer be relied upon.

[0021] Depending on the configuration, if the connection between the safety electronic device and the optical display element is single-channel, interruptions in optical signal generation may occur sequentially over time. As a result, the safety of the system may be improved.

[0022] Depending on the configuration, if the connection between the safety electronic device and the optical display element is multi-channel or n-channel, interruptions in optical signal generation may occur repeatedly and simultaneously. As a result, the safety of the system may be further improved.

[0023] Depending on the embodiment, while measuring the optical signal, at least one parameter of the optical signal or the presence of the optical signal is measured by a safety electronic device. The parameters of the optical signal include at least one of the following: light spectrum, light flux, illuminance, or specific modulation. As a result, it becomes possible to set different configurations of the optical signal and detect them by optical sensors.

[0024] In some embodiments, the output of the alarm or the detection of a fault is effected at a receiving point, either wirelessly or by wire. As a result, in order to improve safety, the alarm can be transmitted to a specific location where there is an alarm.

[0025] By referring to the accompanying drawings and the detailed description given hereinafter, the present invention will be more fully understood, and many advantages of the present invention will be appreciated.

Brief Description of the Drawings

[0026] [Figure 1] A schematic diagram of an emergency stop switch according to the background of the present invention is shown. [Figure 2] A schematic diagram of a monitoring system for an emergency stop switch according to a first aspect is shown. [Figure 3A] A first aspect of a safety electronic device is shown. [Figure 3B] A first aspect of a safety electronic device is shown. [Figure 3C] A first aspect of a safety electronic device is shown. [Figure 3D] A first aspect of a safety electronic device is shown. [Figure 4A] A second aspect of a safety electronic device is shown. [Figure 4B] A second aspect of a safety electronic device is shown. [Figure 5] A schematic diagram of a monitoring system for an emergency stop switch according to a second aspect is shown. [Figure 6] An example of an optical sensor is shown. [Figure 7] A flowchart of a method for a monitoring system for an emergency stop switch according to FIGS. 2 and 5 is shown.

Modes for Carrying Out the Invention

[0027] Next, the present invention will be described with reference to the drawings. It goes without saying that the embodiments of the present invention described herein are merely illustrative and do not in any way limit the scope of protection of the claims. The present invention is defined by the claims and their equivalents. It goes without saying that features of one embodiment of the present invention may be combined with features of another embodiment or other embodiments of the present invention, provided they are not mutually exclusive.

[0028] Figure 2 shows a schematic diagram of a monitoring system 100 for an emergency stop switch according to the first embodiment. The monitoring system 100 includes an operating element 5 and a safety electronic device SE. The operating element 5 includes a first switch S1, a second switch S2, an optical display element LM, and an optical sensor OS. The operating element 5 is at least one of a switch, lever, button, or push button for rotation [shifting], pushing, or pulling.

[0029] The first switch S1 and the second switch S2 are connected to the safety electronic device SE. The configuration of the first switch S1 and the second switch S2 depends on the operating element 5. The first switch S1 and the second switch S2 of the operating element 5 of the type described above are known, and therefore no further details will be given here.

[0030] An optical display element LM can generate or convert an optical signal based on an electrical signal, such as current and / or voltage. An example, but not limited to, the optical display element LM is an LED or a bulb. In this case, the optical display element LM comprises at least one individual optical display element. The optical display element LM may comprise multiple individual optical display elements LM. The frequency spectrum of the optical signal extends from visible light to near-infrared and mid-infrared light and may be modulated by a safety electronic device SE.

[0031] The optical display element LM is connected to the single-channel or multi-channel safety output section of the safety electronic device SE in a single-channel or multi-channel configuration. The safety electronic device SE controls the optical display element LM with an electrical signal, which may be influenced and modulated. By influencing the electrical signal, one or more parameters of the optical signal may be set. The adjustable parameters of the optical signal are at least one of the following: light spectrum, luminous flux, illuminance, or specific modulation. As a result, the safety of the emergency stop switch is improved, and the application of the emergency stop switch may be individually adapted.

[0032] Here, we will describe a typical structure of a safety electronic device SE with reference to Figures 3A to 3B.

[0033] Figures 3A to 3D, without limiting the invention, illustrate selected examples and possibilities of how a safety electronic device SE may be configured as a two-channel or multi-channel system with respect to the switching off of equipment or machinery at the safety output unit A. When the safety electronic device SE comprises multiple safety input units E and multiple safety output units A, these inputs E and outputs A may constitute channels K. This is referred to as a multi-channel or n-channel implementation. Even if switching off fails on multiple channels, for example, n-1 channels, the equipment can still be reliably switched off via the remaining channels. For example, even if four out of five channels fail, the equipment can still be reliably switched off. Therefore, the more channels that are adapted, the greater the safety in the case of a multi-channel implementation. When the safety electronic device SE comprises only one safety input unit E and one safety output unit A, forming a channel, this is referred to as an external single-channel implementation consisting of a display element LM and / or an optical sensor OS. That said, any multi-channel implementation may be internally.

[0034] At each channel K or after each channel K, a feedback signal BACK is tapped off and fed back to the safety electronic device SE to monitor the switching of channel K with respect to safety or the degree of safety. In one embodiment, the feedback signal BACK represents a basic implementation of safety output unit A. In a further embodiment, the feedback signal BACK is required for a basic implementation of safety output unit A. Through the feedback signal BACK, the safety electronic device SE reliably detects faults, thereby forming safety output unit A.

[0035] As shown in Figure 3A, the safety electronic device SE is implemented with two channels: a first channel K1 and a second channel K2. The first safety output unit A includes the first channel K1 and the second channel K2. The display element LM is connected to output contact A1+ via channels K1 and K2, and on the other hand, to the safety electronic device SE at the second output contact A1-.

[0036] Figure 3B shows a second embodiment of the assembly based on Figure 3A, the difference being that the second channel K2 is located at the second output contact A1- of the safety output unit A.

[0037] Figure 3C shows a further embodiment in which a first display element LM1 and a second display element LM2 are connected to the safety electronic device SE for monitoring. In this case, the illustrated configuration corresponds to the configuration in Figure 3A, except that it is a two-channel configuration. The first display element LM1 is separately connected to output contact A1+ via both channels K1 and K2, and on the other hand to the safety electronic device SE at the second output contact A1-. The second display element LM2 is separately connected to output contact A2+ via both channels K1 and K2, and on the other hand to the safety electronic device SE at the second output contact A2-. This example illustrates how multiple display elements LM can be separately connected and monitored at the safety output section of the safety electronic device SE.

[0038] Figure 3D shows a second embodiment of the assembly based on Figure 3B, the difference being that the first display element LM1 and the second display element LM2 are connected in series and connected to the safety electronic device via the first output contact A1+ and the second output contact A1-. In this case, the first channel K1 is provided at the first output contact A1+, and the second channel K2 is provided at the second output contact A1-.

[0039] Figures 4A and 4B, without limiting the invention, illustrate selected examples and possibilities of how the safety electronic device SE may be configured as a single channel or an n-channel system in the safety input section E. Input E may be monitored via switches and feedback. If a failure occurs in n-1 channels, a valid input is still detected. For example, even if two of the three channels fail, the safety electronic device SE can still reliably detect the input signal via the feedback signal BACK.

[0040] Figure 4A shows a safety electronic device SE equipped with channels K1 and K2 for single-channel connection of an optical sensor OS. The optical sensor OS is connected to the safety electronic device SE via a first safety input section E1, whose input contacts E1+ and E1- are connected to the first channel K1 and the second channel K2, respectively.

[0041] Figure 4B shows a further embodiment of how multiple optical sensor OSs can be connected to the safety input section E of the safety electronic device SE. In this case, the first optical sensor OS1 is connected to the safety electronic device SE via the first channel K1. The second optical sensor OS2 is connected to the safety electronic device SE separately from the first channel K1 via the second channel K2. As a result, a complete two-channel system with internal and external two-channel implementations is achieved.

[0042] The examples and possibilities of how the display element LM may be connected to one or more safety output units A and the optical sensor OS may be connected to one or more safety input units E using SE, as shown in Figures 3A to 4B, can be combined with each other in a manner that is convenient, desirable, or not mutually exclusive.

[0043] Figure 5 is a schematic diagram of the monitoring system 100 for an emergency stop switch according to the second embodiment. In this case, the monitoring system 100 according to the second embodiment differs from the monitoring system 100 according to the first embodiment in that the optical sensor OS is not housed in the operating element 5. The optical sensor OS of the monitoring system 100 according to the second embodiment is provided in the safety electronic device SE. The optical signal of the optical display element LM is sent from the optical display element LM to the optical sensor OS via the optical fiber cable LWL. The structure of the remaining components corresponds to that of the monitoring system 100 according to the first embodiment. For this reason, the same reference numerals are used for the same components and are not repeated here.

[0044] Figure 6 shows another example of the optical sensor OS of the monitoring system 100 according to the first and second embodiments. The optical sensor OS comprises at least one of a photoresistor OSa, a photodiode OSb, and a phototransistor OSc.

[0045] The more light that shines on the photoresistor OSa, the lower its electrical resistance becomes. This function is due to the internal photoelectric effect in the layer composed of amorphous semiconductor material. Compared to other light sensors, the response of a photoresistor is very slow.

[0046] A photodiode OSb is a semiconductor diode that converts light in the visible, infrared, or ultraviolet region into an electric current or voltage at a pn junction or pin junction by the internal photoelectric effect in order to receive information transmitted along with an optical signal.

[0047] The phototransistor OSc comprises a photosensitive photodiode connected to an amplifier transistor. From a circuit perspective, the photosensitive photodiode is in parallel with the collector-base terminal of the transistor. Incident light generates a weak current due to the internal photoelectric effect. This current is amplified in the transistor by the current amplification factor to become a collector current.

[0048] For more information on this point, please refer to the known literature on the photoelectric effect.

[0049] Figure 7 shows flowcharts of the monitoring system 100 for an emergency stop switch according to the first and second embodiments. In step S1, an optical signal is generated by a safety electronic device SE by driving an optical display element LM with an electrical signal. Simultaneously, in or after each channel K, the electrical signal is fed back to the safety electronic device SE with a feedback signal BACK tapped off to monitor the switching of channel K regarding safety or the degree of safety. In step S2, at least one of the parameters of the optical signal or the presence of the optical signal is measured. In this case, at least one of the optical spectrum, luminous flux, illuminance or specific modulation of the optical signal is measured. In step S3, the optical display element LM is driven by an electrical signal via the safety electronic device SE during a period t DThe connection between the safety electronic device SE and the optical display element LM is single-channel, and the interruptions may occur sequentially in time. If the connection between the safety electronic device SE and the optical display element LM is multi-channel (see Figures 3A and 3B), the interruptions may occur simultaneously or with a time offset. The time offset of the interruptions may allow for the detection of cross-connections between safety output units A, between safety input units E, and between safety output unit A and safety input unit E. One or more of these interruptions are measured by at least one optical sensor OS. In step S4, the safety electronic device SE compares the generated electrical signal with the measured optical signal. The interruption and measurement / comparison of the electrical signal is called "dynamization". Thus, dynamization allows one or more safety input units E and one or more safety output units A to continuously monitor their function. Therefore, all possible failures can be detected at the latest during the next dynamization period. The degree of dynamization, i.e., how often and when it is repeated, is proportional to the level of safety requirements for the system. Safety requirements depend on the risk potential or risk situation, respectively. Therefore, for example, safety electronic devices and functions in a nuclear power plant are, in effect, continuously and dynamically controlled and monitored. Thus, dynamization may be considered a type of functional test. Dynamization may be completely omitted if the system is configured as an extra system implemented in isolation and secrecy, and as a result, it is technically guaranteed that it cannot be mechanically cross-connected or ground-connected, for example.

[0050] In step S5, if the generated optical signal (which may be an electrical signal) deviates from the measured optical signal, an alarm is output. The alarm output is sent to a receiving point wirelessly or via a wired connection. The alarm may be an analog or digital signal. The receiving point may generate a control command and / or an acoustic or optical signal from the alarm. For example, the control command may be to shut down the machine. [Explanation of Symbols]

[0051] 100 Monitoring Systems 5 Operating parts LMx display element OSX Optical Sensor SE safety electronic equipment A Safety output section Ax+, Ax- output contacts E Safety Input Section Ex+, Ex- input contacts LWL Fiber Optic Cable Sx Switch Mx probe OSa Photoresistor OSb photodiode OSc phototransistor t D period PL Performance Level SIL safety level

Claims

1. A monitoring system for the optical display element of an emergency stop switch, The monitoring system is near An operating element equipped with the aforementioned optical display element, An optical sensor configured to sense the optical signal of the aforementioned optical display element, The system comprises a safety electronic device connected to the optical display element and the optical sensor, The aforementioned safety electronic device comprises a safety output unit and a safety input unit. The safety electronic device is connected to the optical display element via the safety output unit. The safety electronic device is connected to the optical sensor via the safety input unit in the monitoring system.

2. A monitoring system for the optical display element of an emergency stop switch, The monitoring system is near An operating element equipped with the aforementioned optical display element, At least one fiber optic cable, A safety electronic device equipped with an optical sensor, The aforementioned safety electronic device comprises a safety output unit and a safety input unit. The safety electronic device is connected to the optical display element via the safety output unit. The safety electronic device is connected to the optical sensor via the safety input unit. A monitoring system in which at least one of the optical fiber cables leads the optical signal of the optical display element to the optical sensor.

3. The monitoring system according to claim 1 or 2, wherein the safety electronic device is connected to the optical display element via a first channel and a second channel.

4. The monitoring system according to claim 1 or 2, wherein the safety electronic device is connected to the optical sensor via a first channel and a second channel.

5. The monitoring system according to claim 3 or 4, wherein the current or voltage from the safety electronic device is fed back to the safety electronic device as a feedback signal via at least one of the first channel and the second channel.

6. The monitoring system according to claim 1 or 2, wherein the optical sensor comprises at least one of a photoresistor, a photodiode, and a phototransistor.

7. The optical display element comprises at least one display element and / or, The monitoring system according to claim 1 or 2, wherein the optical sensor comprises at least one optical sensor.

8. The monitoring system according to claim 1 or 2, wherein the safety output unit comprises at least one first output contact and at least one second output contact.

9. The monitoring system according to claim 1 or 2, wherein the safety input unit comprises at least one first input contact and at least one second input contact.

10. A method for a monitoring system for an optical display element of an emergency stop switch, The aforementioned method, The steps include generating an optical signal by applying current or voltage to the optical display element via a safety electronic device, The safety electronic device measures the optical signal via an optical sensor, The steps include interrupting the generation of the optical signal for a certain period of time and measuring the interruption of the optical signal via the optical sensor using the safety electronic device, The safety electronic device, when the current or voltage is applied, performs the step of comparing the generated optical signal with the measured optical signal, A method comprising the step of outputting an alarm if there is a deviation in the comparison between the generated optical signal and the measured optical signal when the aforementioned current is applied.

11. The method according to claim 10, further comprising the steps of: interrupting the generation of the optical signal for a certain period of time and measuring the interruption of the optical signal via the optical sensor by the safety electronic device; and continuously monitoring at least one of the safety input and safety output sections of the safety electronic device by repeating the steps of: comparing the generated optical signal with the measured optical signal when the current or voltage is applied by the safety electronic device.

12. The method according to claim 10, wherein, when the connection between the safety electronic device and the optical display element is single-channel, the generation of the optical signal is repeatedly interrupted in a time-sequential manner.

13. The method according to claim 10, wherein, when the connection between the safety electronic device and the optical display element is multi-channel, the generation of the optical signal is repeatedly interrupted simultaneously.

14. While the optical signal is being measured, at least one of the parameters of the optical signal or the presence of the optical signal is measured by the safety electronic device. The method according to claim 10, wherein the parameters of the optical signal include at least one of a light spectrum, luminous flux, illuminance, or specific modulation.

15. The method according to claim 10, wherein the output of the alarm is transmitted to a receiving point wirelessly or via a wire.

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