Flame monitor, combustion chamber and method for monitoring a combustion chamber

Abstract

The invention relates to a flame monitor for monitoring a combustion chamber with respect to the presence of a flame, having a flame sensor for detecting a physical variable of the flame and for generating an electrical sensor signal, a two-channel evaluation circuit for determining whether the sensor signal corresponds to a flame and for outputting an output signal, having a first channel comprising a first analog-digital converter, a first microcontroller belonging to a digital diagnosis and comparison unit for evaluating the first signal and a first relay, and a second channel comprising a second analog-digital converter, a second microcontroller and a second relay, the diagnosis and comparison unit being designed to perform a comparison of the first evaluation result and the second evaluation result and to influence the output signal in accordance with the comparison result, characterized in that it is designed to compare the signals obtained from one channel with a desired value both by means of the first microcontroller and by means of the second microcontroller and to optionally initiate a fault continued operation mode of the evaluation circuit in accordance with the result.

Description

Technical Field

[0001] This invention relates to a flame monitor for monitoring at least one sub-region of a combustion chamber in terms of the presence or absence of a flame. The flame monitor comprises: a flame sensor for detecting physical variables of the flame, particularly the intensity of electromagnetic radiation, and for generating an associated electrical sensor signal; and a dual-channel evaluation circuit connected downstream of the flame sensor for determining whether the sensor signal generated by the flame sensor corresponds to a flame, and for outputting an output signal indicating the presence or absence of a flame in a safety-oriented manner. The dual-channel evaluation circuit further comprises: establishing a first channel for processing the sensor signal, the first channel including a second analog circuit... The system includes an analog-to-digital converter (ADC), a first microcontroller belonging to a digital diagnostic and comparison unit for evaluating a first signal obtained from the first ADC, and a first relay in a relay circuit controlled by the first microcontroller; and a second channel for processing sensor signals, the second channel including a second ADC in an analog circuit, a second microcontroller belonging to the digital diagnostic and comparison unit for evaluating a second signal obtained from the second ADC, and a second relay in a relay circuit controlled by the second microcontroller, wherein the diagnostic and comparison unit is configured to perform a comparison of a first evaluation result of the first microcontroller and a second evaluation result of the second microcontroller, and to influence the output signal based on the comparison result.

[0002] The present invention also relates to a combustion chamber having a flame detector of the type mentioned earlier.

[0003] The present invention also relates to a method for monitoring at least one sub-region of a combustion chamber regarding the presence or absence of a flame, particularly of the type mentioned above and / or having a flame detector of the type mentioned earlier, the method comprising the steps of: detecting physical variables of a flame, particularly the intensity of electromagnetic radiation, by means of a flame sensor, and generating an associated electrical sensor signal; determining whether the sensor signal generated by the flame sensor corresponds to a flame by means of a dual-channel evaluation circuit connected downstream of the flame sensor, and outputting an output signal indicating whether a flame is present or absent in a safety-oriented manner; in the first channel of the evaluation circuit, by means of an analog circuit... The sensor signal is processed by a first analog-to-digital converter (ADC), a first microcontroller belonging to the digital diagnostics and comparison unit for evaluating a first signal obtained from the first ADC, and a first relay controlled by the first microcontroller in a relay circuit; and in a second channel of the evaluation circuit, the sensor signal is processed by a second ADC in an analog circuit, a second microcontroller belonging to the digital diagnostics and comparison unit for evaluating a second signal obtained from the second ADC, and a second relay controlled by the second microcontroller in a relay circuit; a comparison is performed between a first evaluation result of the first microcontroller and a second evaluation result of the second microcontroller, and the output signal is affected according to the comparison result. Background Technology

[0004] In conjunction with this invention, the term "outputting an output signal indicating whether a flame is present or not in a safety-oriented manner" is particularly understood to mean that if the evaluation circuit no longer determines that the sensor signal generated by the flame sensor corresponds to a flame even on only one of the two channels, the evaluation circuit is preferably able to output an output signal indicating the absence of a flame after a predetermined detection time, for example, about 1 second to about 5 seconds, in the case that the flame has stopped.

[0005] In conjunction with this invention, the term "affecting the output signal based on the comparison result" is particularly understood to mean that, in the case where the comparison result of the first evaluation result of the first microcontroller and the second evaluation result of the second microcontroller is negative, the output signal can specifically signal fault cessation or interference shutdown. In conjunction with this invention, "the comparison result is negative" is particularly understood to mean that, preferably, even after considering tolerance deviations, the evaluation result of the first microcontroller deviates from the evaluation result of the second microcontroller. In conjunction with this invention, "fault cessation" or "interference shutdown" is particularly understood to mean that, due to the aforementioned deviation, due to other faults determined by the evaluation circuit, or other interference in the evaluation circuit, for safety reasons, the output signal outputs an output signal indicating the absence of a flame. Other faults or other interferences in the evaluation circuit are particularly understood to be the faults or interferences described in this disclosure.

[0006] The type of flame detector mentioned at the beginning is known from the prior art. For example, the flame detector "D-LX 201" of DURAG Group involves the type of flame detector mentioned above. Summary of the Invention

[0007] The object of this invention is to improve the flame monitors, combustion chambers, and / or methods of the type mentioned above. In particular, the object of this invention is to provide flame monitors, combustion chambers, and / or methods of the type mentioned above that can achieve improved availability of combustion chambers and combustion devices or process equipment equipped with said flame monitors without compromising the safety requirements of said flame monitors, combustion chambers, and / or methods.

[0008] The objective is achieved through the subject matter of embodiments of the present invention.

[0009] The present invention particularly provides a flame monitor of the type mentioned at the beginning, characterized in that a diagnostic and comparison unit is configured to compare a signal obtained from one of the two channels with a corresponding expected value, not only by means of a first microcontroller but also by means of a second microcontroller, and optionally activate a failure operation mode of the evaluation circuit based on the comparison result. The present invention also provides a combustion chamber having such a flame monitor.

[0010] Furthermore, the present invention also provides a method of the type mentioned above, characterized by comprising the steps of comparing a signal obtained from one of the two channels with a corresponding desired value by means of a first microcontroller and a second microcontroller, and optionally activating a fault-continued operation mode of the evaluation circuit based on the comparison result.

[0011] In conjunction with the present invention, the term "fault-continued operation mode" is particularly understood as follows: although the comparison between the first evaluation result of the first microcontroller and the second evaluation result of the second microcontroller is negative, the evaluation circuit is able to continue to indicate the presence of flame by means of the output signal, rather than forcibly triggering a fault stop signal or interference shutdown signal as the output signal of the evaluation circuit, at least for a predetermined time period.

[0012] In conjunction with this invention, the term "optionally activated" fault-continued operation mode is understood to mean that when a fault occurs in the corresponding channel, the evaluation circuit does not forcibly, or at least not immediately, output an output signal indicating the absence of a flame. More precisely, by optionally activating the fault-continued operation mode, although the evaluation circuit still has the possibility of triggering fault cessation in the specific circumstances described in this disclosure, on the other hand, according to the invention, the evaluation circuit also has the possibility that, in the fault-continued operation mode, particularly under the conditions mentioned in this invention, for example using another of the two channels, the continued operation, preferably time-limited, of at least one sub-area of ​​the combustion chamber monitored by the flame monitor, or even the entire combustion chamber, can be achieved. Therefore, during the fault-continued operation mode, the flame monitor continues to generate an output signal indicating the presence of a flame.

[0013] Furthermore, an advantage of the present invention is that, for example, by comparing the signal obtained from one of the two channels with its corresponding expected value, if the comparison shows that the obtained signal does not correspond to the expected value, the channel can be determined to be faulty. Simultaneously, according to the invention, the comparison is performed not only by means of the first microcontroller but also by means of the second microcontroller. This advantageously eliminates the possibility that the fault identified in the channel resides in one of the microcontrollers of the diagnostic and comparison unit. Therefore, the present invention can determine that the fault is in the analog section or analog portion of the channel. Here, the invention preferably also considers that a portion of the analog-to-digital converter in the corresponding channel is analog, but also has a digital portion, i.e., digital processing and forwarding of digital signals, and the fault of the digital signal is preferably also considered by the diagnostic and comparison unit or both microcontrollers, i.e., preferably also included in the area of ​​continued operation of a single channel. Thus, the present invention provides the option of initiating a fault-prone continued operation mode of the evaluation circuit without compromising the safety requirements of the flame monitor. Because, due to the present invention, the evaluation circuit can identify, in such cases, the possibility that at least only the inspected channel is faulty, but the flame still exists.

[0014] The continued operation mode has significant advantages. This is because the invention recognizes that the flame detectors mentioned earlier are almost exclusively used in the combustion chambers of large-scale technical equipment. This relates, for example, to complex combustion equipment or combustion processes involving a large quantity of viable fuels such as gas, oil, lignite, or hard coal in continuous operation. However, it can also relate to blast furnaces in the steel industry, chemical plants, waste incineration plants, or cement manufacturing plants. The invention now recognizes that, for all these large-scale technical combustion processes, it is of paramount importance, on the one hand, for safety reasons, that if the evaluation circuit no longer determines that the sensor signal generated by the flame sensor corresponds to a flame in one of the two channels, the evaluation circuit generates and outputs an output signal indicating the absence of a flame, such that, for example, the valve of the fuel delivery device to the combustion chamber can be closed by saying the output signal. In this way, fuel, such as gas, is prevented from continuing to flow in the combustion chamber, even though the flame in the combustion chamber may have been extinguished.

[0015] However, the present invention also recognizes that, as is common to all such large-scale technical combustion processes, shutting down and, in particular, starting up such equipment is associated with significant costs. Therefore, a major advantage of the present invention is that continued operation of the combustion chamber is feasible through an optional fail-safe operation mode. This improves equipment availability. During the continued operation of the combustion chamber, it can be advantageously determined, for example, whether another channel indicates the presence of a flame. If so, operation can continue in the fail-safe operation mode, for example, until maintenance of the faulty channel continues. In other words: if a fault-free channel identifies the presence of a flame (“flame present”), then even with a fault in the redundant channel, external signaling or fuel delivery can continue. In principle, there is a possibility of switching to the fail-safe operation mode, even in the state of “flame off”. The flame monitor being in the state of “flame present” makes switching to the fail-safe operation mode not a mandatory condition. Thus, the operator of the combustion chamber can advantageously start the burner or deliver fuel to the burner even if there is a fault in the flame monitor. This invention relates to a flame monitor or method for monitoring at least one sub-region of a combustion chamber in terms of the presence of a flame. Therefore, this includes any part or sub-region of the combustion chamber, but also the entire combustion chamber, i.e., the presence or absence of a flame anywhere within the combustion chamber.

[0016] Therefore, the present invention also advantageously includes different safety assessments: in one case, for example, checking whether a flame exists in a specific sub-region of the combustion chamber, such as in a sub-region of the combustion chamber associated with a specific burner of the combustion chamber, i.e., monitoring a single burner. In another case, for example, it is preferable to check whether a flame exists anywhere in the combustion chamber. Thus, combustion chamber monitoring of the entire combustion chamber is performed. For this purpose, the flame sensor can preferably observe the combustion chamber with a cone of view or field of view having a specific angle. Here, the flame sensor can preferably be configured and its sensitivity adjusted such that an electrical sensor signal is generated corresponding to the electromagnetic radiation present in the sub-region of the combustion chamber where the flame is positioned. The sub-region can preferably be a sub-region belonging to a specific burner of the combustion chamber. However, the flame sensor can also, for example, preferably be configured and its sensitivity adjusted such that if a flame is detected anywhere in the combustion chamber based on the corresponding electromagnetic radiation, an electrical sensor signal is generated, i.e., the combustion chamber is thus monitored as a whole.

[0017] In one embodiment of the invention, the comparison of a signal obtained from one of the two channels with its corresponding expected value can be triggered by a comparison of a first evaluation result and a second evaluation result from a first microcontroller or a second microcontroller with respect to a first signal obtained from a first analog-to-digital converter or a second signal obtained from a second analog-to-digital converter. In other words, in this embodiment, for example, the comparison of the evaluation results of the signals obtained from the two analog-to-digital converters indicates a difference between the two signals, preferably a difference exceeding tolerance limits, only when the comparison is made by means of two microcontrollers.

[0018] This discrepancy indicates a fault in one of the two channels. Therefore, in this embodiment, the comparison of the signal obtained from one of the two channels with the expected value according to the invention is performed only when such a fault notification occurs. In this way, processing power in the involved electronic processing components can be saved in particular, because the comparison of the signal obtained from one of the two channels with the corresponding expected value according to the invention is not performed continuously in this embodiment.

[0019] Not only in the case where the signal obtained from one of the two channels is compared with the corresponding expected value regardless of the evaluation result of the sensor signal according to the present invention, but also in the above-described embodiment where the comparison is triggered only by the result of the comparison of the evaluation result, the present invention benefits from comparing not only by means of the first microcontroller but also by means of the second microcontroller according to the present invention, so as to advantageously eliminate the presence of a fault in one of the microcontrollers of the diagnostic and comparison unit before initiating the fault-continuing operation mode.

[0020] Therefore, it is advantageous to allow at least one sub-area of ​​the combustion chamber, or even the entire combustion chamber, monitored by the flame monitor according to the invention, to continue operating in a fault-tolerant mode of the flame monitor for at least, for example, a predetermined period of about 24 hours. This is done, for example, by using one of the two channels to evaluate the sensor signal of the flame sensor. If the other channel indicates the presence of a flame, the monitored combustion chamber can continue operating preferably for the predetermined period until, for example, the faulty channel is repaired or reset. However, if the other channel does not indicate the presence of a flame, the evaluation circuit outputs an output signal indicating the absence of a flame, which can then, for example, be used to close the valve and stop fuel delivery to the monitored combustion chamber, such that the option of activating the fault-tolerant mode according to the invention does not compromise the safety level of the flame monitor according to the invention. It is also advantageous to activate the fault-tolerant mode if a fault is identified in one of the two channels in the state "Flame Stop". In this way, the operator of the combustion chamber can then advantageously start the burner or deliver fuel to the burner even if a fault exists in the flame monitor.

[0021] A preferred embodiment of the invention is characterized in that the diagnostic and comparison unit is configured to initiate a fault continuation mode only when the result of a comparison by means of both the first and second microcontrollers is, preferably after considering tolerance deviations, that the signal compared to the expected value deviates from the expected value. This advantageously ensures that, for example, when the result of a comparison by means of only one of the two microcontrollers is that the signal compared to the expected value deviates from the expected value, the fault continuation mode is not initiated. This is because in this case, a fault exists in one of the two microcontrollers in the diagnostic and comparison unit. In this situation, continued operation should not proceed.

[0022] More precisely, for safety reasons, the fault-continuation operation of the flame monitor or its operation in fault-continuation mode should preferably only be performed if the diagnostic and comparison unit is fault-free. This is, for example, when the result of the comparison by means of both the first and second microcontrollers is confirmed to be a signal compared to the expected value, preferably after considering, for example, a tolerance deviation of about 3 seconds. In this case, it is advantageous to simultaneously determine that a fault exists in one of the two channels outside the diagnostic and comparison unit. For example, if it is determined during a second measurement by means of the other channel that the two comparison results are consistent with the expected value, the implementation thus provides the possibility of explicitly associating the fault with one of the two channels, while simultaneously ruling out a fault in the diagnostic and comparison unit itself.

[0023] Another embodiment of the invention is characterized in that the diagnostic and comparison unit is configured such that, when the result of a comparison, either solely by means of the first microcontroller or solely by means of the second microcontroller, is that the signal compared to the expected value preferably deviates from the expected value after considering tolerance deviations, the fault-continued operation mode is not initiated. Instead, a fault stop is preferably triggered by the evaluation circuit after a predefined fault tolerance time. In this case, one of the two microcontrollers in the diagnostic and comparison unit, and thus the diagnostic and comparison unit, is faulty and is no longer fault-free. Therefore, this embodiment provides the advantage of indicating fault stop independently of the result of comparing the evaluations of the two sensor signals. This is because, in the case of a faulty diagnostic and comparison unit, it is no longer feasible to evaluate the sensor signal of the flame sensor in accordance with regulations.

[0024] More precisely, by means of the described embodiment, fault shutdown can advantageously be triggered regardless of whether the comparison between the first evaluation result of the first microcontroller with respect to the first signal obtained from the first analog-to-digital converter and the second evaluation result of the second microcontroller with respect to the second signal obtained from the second analog-to-digital converter indicates a difference in the first and second signals, thereby indicating the cessation of flame if necessary. In other words, the described embodiment of the invention further enhances the safety of the flame monitor according to the invention because it enables continuous monitoring of the diagnostic and comparison unit and the corresponding triggering of fault shutdown by the evaluation circuit or the flame monitor according to the invention, thereby shutting down the fuel delivery device. In this way, the described embodiment of the invention provides, within the scope of safety-oriented operation of the actuator by the evaluation circuit, not only the possibility of shutting down the fuel delivery device in the event of different evaluation results from the first and second microcontrollers, but also, additionally, the possibility of shutting down the fuel delivery device in the event of a fault in the diagnostic and comparison unit.

[0025] One embodiment of the invention is characterized in that the signal obtained from one of the two channels is a signal obtained from the analog-to-digital converter in said channel. This embodiment can advantageously achieve simple identification of faults in the signals read by the two microcontrollers, for example, by identifying signal overload or by identifying harmonic signals in the signal obtained from the analog-to-digital converter, or by identifying that no valid value is obtained from the analog-to-digital converter. For example, the latter case occurs when there is a data security indication fault in the digital communication between the analog-to-digital converter and one or both microcontrollers.

[0026] In one embodiment of the invention, a first analog switcher and a second analog switcher are provided. The first analog switcher is located upstream of a first analog-to-digital converter in a first channel in an analog loop and can be switched by a diagnostic and comparison unit. The second analog switcher is located upstream of a second analog-to-digital converter in a second channel in an analog loop and can be switched by a diagnostic and comparison unit. The diagnostic and comparison unit is configured to, by means of switching the first analog switcher and / or the second analog switcher, preferably within a predetermined test time period, replace the sensor signal and transmit a test signal for testing the analog-to-digital converter, preferably having a predetermined amplitude and / or a predetermined frequency, to the corresponding analog-to-digital converter.

[0027] In the described embodiment, it is advantageous to diagnose one of the two channels using a separate test signal. The test signal is preferably generated by at least one test signal generator in at least one of the two microcontrollers. Therefore, in the described embodiment of the invention, the sensor signal from the flame sensor, which is preprocessed by a corresponding amplifier if necessary, is not directly directed to the analog-to-digital converter (ADC) in the corresponding channel, but is instead directed to the ADC via an analog switch provided in the corresponding channel. In this way, according to the invention, it is feasible to provide the test signal to the corresponding ADC instead of the sensor signal by switching the corresponding first analog switch and / or the corresponding second analog switch, preferably limited to a predefined test period of, for example, about 100 ms to about 1000 ms. The corresponding ADC is then tested or diagnosed according to the invention using the test signal. Because, according to the invention, the digital signal converted from the test signal by the corresponding ADC is fed to the two microcontrollers of the diagnostic and comparison unit, allowing the comparison of the signal with the corresponding expected value according to the invention to be performed. Therefore, according to the present invention, it can be determined that either the channel, in particular the analog-to-digital converter being tested, is fault-free because the signal obtained from the analog-to-digital converter corresponds to the expected value, or when the obtained signal, even after deducting the corresponding tolerance deviation, does not correspond to the expected value, not only by means of the first microcontroller but also by means of the second microcontroller, the fault-continued operation mode can be initiated by the evaluation circuit.

[0028] In the described implementation, the desired value may be, for example, a specific test pattern. The desired value or test pattern is preferably exchanged via internal data exchange between the two microcontrollers, such that the two microcontrollers have the same desired value or the same test pattern.

[0029] Preferably, there is only one test signal generator or only one test signal source for the test signal. In this way, the safety level of the flame monitor according to the invention also advantageously extends to the test signal generator. Because if a fault occurs in the test signal generation, not only will the test of one of the two analog-to-digital converters fail, but due to the fault in the test signal generation, a deviation from the expected value will also occur in the subsequent test of the other channel, so that at the latest then preferably by triggering a fault stop via the evaluation circuit or the flame monitor. This is advantageous because the test signal generation or test signal generator is also incorporated into the diagnostic and comparison unit, which should be fault-free to maintain the safety level preferably sought here.

[0030] The test signal in this embodiment is directed to a corresponding analog switch. The corresponding analog switch is used to disconnect or switch the corresponding sensor signal. Preferably, before the test sequence begins, the corresponding sensor signal is disconnected via the corresponding analog switch in the channel, and instead, the test signal is directed to the corresponding analog-to-digital converter via the corresponding analog switch.

[0031] The implementation of the invention using test signals described above offers particular advantages, especially in that the testing of analog-to-digital converters in a particular channel can be performed independently of the sensor signals in the corresponding channel.

[0032] One embodiment of the invention is characterized in that a first analog switcher can be switched by a first microcontroller via a first control line, and a second analog switcher can be switched by a second microcontroller via a second control line. The state of the first control line can be monitored by the second microcontroller via a first readback line to the second microcontroller by comparing it with the desired state of the first control line. The state of the second control line can be monitored by the first microcontroller via a second readback line to the first microcontroller by comparing it with the desired state of the second control line. Wherein, when the state of the first control line preferably deviates from the desired state of the first control line after considering tolerance deviations and / or the state of the second control line preferably deviates from the desired state of the second control line after considering tolerance deviations, a fault stop of the evaluation circuit is preferably triggered after, for example, a predefined readback fault tolerance time of approximately 1 ms to approximately 100 ms. This embodiment particularly provides the advantage that the corresponding control line for the analog switcher in one of these channels can be monitored by means of the microcontroller of the other channel via its corresponding readback line. This advantageously eliminates the possibility of the corresponding analog switcher being faultily operated and causing a fault in this manner.

[0033] A preferred embodiment of the invention is characterized by having a first additional analog switch, controllable by a diagnostic and comparison unit, in the first channel to disconnect the test signal in the first channel, and a second additional analog switch, controllable by the diagnostic and comparison unit, in the second channel to disconnect the test signal in the second channel. A particular advantage of this embodiment is the provision of a second fault safety by including additional analog switches associated with the respective analog switches. This is because it is possible that the first fault remains undetected, allowing any further fault to occur within 24 hours. As a result of this, the test signal described above could, for example, simulate a flame, which is a dangerous fault, i.e., a fault that compromises the safety level of the flame detector according to the invention.

[0034] A preferred embodiment of the invention is characterized in that a diagnostic and comparison unit is configured to, by means of two microcontrollers, check in the selected channel, after the test signal in the selected channel is disconnected and before the sensor signal is turned on, whether the test signal is disconnected and whether the corresponding additional analog switcher for disconnecting the test signal in the selected channel is functioning. This embodiment provides additional safety, for example, that the test signal used to check a specific signal may not arrive at the corresponding analog-to-digital converter outside the corresponding test phase or the corresponding test time period, thus potentially malfunctioning the simulation of a flame.

[0035] A preferred embodiment of the invention is characterized in that the signal obtained from one of the two channels is a signal obtained from a relay in said channel. Thus, the relay circuit or a specific relay of the flame detector according to the invention can also be advantageously inspected or diagnosed. Preferably, the signal obtained from the relay is a signal obtained from the relay's readback contact. In this way, obtaining a signal to be compared with a corresponding desired value by means of two microcontrollers can be achieved particularly simply according to the invention. Because by means of the readback contact, it is easy to check whether the load contacts of the corresponding relays are correctly switched, and the relays communicate the flame detector's safety-related flame notifications via output signals.

[0036] A preferred embodiment of the present invention is characterized in that the first relay can be controlled by a first microcontroller via a first relay control line, and the second relay, preferably connected in series with the first relay, can be controlled by a second microcontroller via a second relay control line. The state of the first relay control line can be monitored by the second microcontroller via a first relay readback line to the second microcontroller by comparing it with the expected state of the first relay control line. The state of the second relay control line can be monitored by the first microcontroller via a second relay readback line to the first microcontroller by comparing it with the expected state of the second relay control line. Furthermore, when the state of the first relay control line preferably deviates from the expected state of the first relay control line after considering tolerances and / or the state of the second relay control line preferably deviates from the expected state of the second relay control line after considering tolerance deviations, a fault stop of the evaluation circuit is preferably triggered after, for example, approximately 3 seconds of a predetermined readback fault tolerance time.

[0037] The described embodiment offers the particular advantage of enabling the additional differentiation between faults in the relay channel and faults in one of the microcontrollers in the diagnostic and comparison unit or the microcontroller. This is because, in the described embodiment, each of the other microcontrollers in the diagnostic and comparison unit reads back the corresponding relay control circuit of the corresponding flame relay via its associated relay readback circuit. If the state of the corresponding relay control circuit read back in this manner deviates from the expected state of its associated relay control circuit, a fault is preferably considered to exist in the diagnostic and comparison unit, allowing the fault to be triggered by the evaluation circuit, preferably within a short fault tolerance time.

[0038] On the other hand, if it is determined in the relay control circuit that there is no deviation from the expected state of the corresponding relay control circuit, then when a deviation is found by comparing the signal obtained from one of the two channels with the corresponding expected value using not only the first microcontroller but also the second microcontroller, a fault continuation operation mode can be initiated. Advantageously, the operation of the corresponding relay is not changed here. Furthermore, even when the load contact of the corresponding relay is permanently closed, the flame detector can always notify the external signal of the correct flame report (Flammenmeldung) or flame extinguishment (Flammenabmeldung) via the output signal of the corresponding safety-related relay output terminal of the flame detector. On the other hand, it is advantageous that even if the corresponding readback contact fails, the corresponding relay continues to switch correctly on the load side, allowing the correct flame report to continue to be notified to the external signal via the output signal of the corresponding safety-related output terminal of the flame detector.

[0039] In the described embodiment, two forced-guided relays are preferably used in series, such that if one of these relays fails or switches incorrectly, the other relay remains available to maintain the desired redundancy.

[0040] A preferred embodiment of the invention includes a first amplifier and a second amplifier arranged in an analog circuit. The first amplifier is used to preprocess sensor signals in a first channel for use with a first analog-to-digital converter (ADC), and the second amplifier is used to preprocess sensor signals in a second channel for use with a second ADC. The signal obtained from one of the two channels is the signal obtained from the amplifier in that channel. In this way, diagnosis of the channel according to the invention can be performed in a simple manner and method by comparing the signal obtained from the channel with its corresponding expected value using two microcontrollers. Here, faults in the corresponding channels can preferably be identified by recognizing signal overload or harmonic signals.

[0041] One embodiment of the invention is characterized in that a first amplifier can be controlled by a first microcontroller via a first control line, and a second amplifier can be controlled by a second microcontroller via a second control line. The state of the first control line can be monitored by the second microcontroller via a first amplifier readback line to the second microcontroller by comparing it with a desired state of the first control line. The state of the second control line can be monitored by the first microcontroller via a second amplifier readback line to the first microcontroller by comparing it with a desired state of the second control line. Wherein, when the state of the first control line preferably deviates from the desired state of the first control line after considering tolerance deviations and / or the state of the second control line preferably deviates from the desired state of the second control line after considering tolerance deviations, a fault stop of the evaluation circuit is preferably triggered after, for example, a predetermined readback fault tolerance time of approximately 3 seconds. A particular advantage of this embodiment is that the corresponding control line for the amplifier in one of these channels can be monitored by means of the microcontroller of the other channel via its associated amplifier readback line. This advantageously prevents the corresponding amplifier from being faultily controlled and causing a fault in this manner.

[0042] Another embodiment of the invention is characterized in that the diagnostic and comparison unit is configured such that the comparison of the signal obtained from one of the two channels with the corresponding expected value can be performed alternately by means of the signal obtained from the first channel and by means of the signal obtained from the second channel.

[0043] In this context, the term "alternating" means that the two channels are sequentially subjected to the diagnostic or inspection according to the invention by comparing the signal obtained from one of the two channels with its corresponding expected value using two microcontrollers. This embodiment provides the advantage that while diagnosing a channel according to the invention by comparing the signal obtained from the channel with its corresponding expected value using two microcontrollers, the other channel can continue to evaluate the presence of redundant sensor signals using the corresponding microcontroller of that channel, preferably also using two microcontrollers, thus ensuring uninterrupted measurement overall by means of the flame monitor according to the invention. In other words, according to the invention, uninterrupted measurement during the diagnostic process is also possible, wherein only one of the two microcontrollers calculates the flame decision, i.e., whether the flame is present or absent in the monitored sub-region of the combustion chamber or anywhere in the combustion chamber, and then only informs the other microcontroller of the result. However, according to the invention, uninterrupted measurement during the diagnostic process is also possible by directing the digital signals from the AD converter to the two microcontrollers of the diagnostic and comparison units, respectively, wherein, during the diagnostic process, the signals of signals that are not tested are used by the two microcontrollers for flame decision-making. Therefore, in the latter variant, the two microcontrollers advantageously continue to compute flame decisions independently of each other, even during diagnostics.

[0044] A preferred embodiment of the invention is characterized in that the diagnostic and comparison unit is configured to maintain the fault-continuing operation mode for a predetermined time period. This time period advantageously depends on the probability of a second fault. In other words, the probability of a second fault should be as low as possible within the predetermined time period.

[0045] In a preferred embodiment of the invention, the fault-continuing operation mode includes: the evaluation circuit or flame detector continues to operate only by means of the other of the two channels, i.e., it continues to operate only in a single-channel manner. In this embodiment, it is preferable to continue checking or diagnosing the channel identified as faulty according to the invention. In this regard, a single-channel diagnostic operation of the flame detector is performed. Therefore, in this operation mode, it is not simply a matter of continuing to operate within the scope of the fault-continuing operation mode by means of the unchecked channel, but rather, it is preferable to continue guiding or repeating the checks performed within a predetermined diagnostic time. Here, a decision is made only after a certain number of repetitions of the checks or after the end of the individually predetermined diagnostic time: whether to ultimately operate in the fault-continuing operation mode without further testing of the channel identified as faulty, or whether to switch back to normal dual-channel operation of the evaluation circuit if, for example, it is confirmed during repeated testing of the initially identified faulty channel that it is indeed not faulty. Therefore, the implementation provides increased flexibility when there is a deviation between the signal obtained from one of the two channels by means of two microcontrollers and the corresponding expected value, and especially when determining the duration, continuing or ending a fault-prone operation mode.

[0046] A preferred embodiment of the invention is characterized in that the evaluation circuit only operates single-channel by means of the other channel when the diagnostic and comparison unit classifies the other channel as fault-free. This ensures that, within the fault-continuing operation mode, the circuit does not switch to or continue operating without the faulty channel.

[0047] A preferred embodiment of the invention is characterized in that the diagnostic and comparison unit is configured to, before determining the comparison result, preferably within a predetermined fault tolerance time of approximately 1 second to approximately 10 seconds, perform multiple comparisons, not only by means of a first microcontroller but also by means of a second microcontroller, of the signal obtained from one of the two channels with its corresponding expected value. By employing multiple comparisons in this embodiment, the security of the comparison result is improved.

[0048] A preferred embodiment of the invention is characterized in that the diagnostic and comparison unit is configured such that if it is determined in one of the two channels that the sensor signal generated by the flame sensor does not correspond to a flame, the comparison with the corresponding expected value is preferably performed solely by means of the signal obtained from said channel. In this embodiment, according to the invention, the comparison of the signal obtained from one of the two channels with the corresponding expected value by means of two microcontrollers is advantageously triggered in such a way that the sensor signal generated by the flame sensor does not correspond to a flame, i.e., when, by means of a comparison of the evaluation results of the two channels performed between the two microcontrollers, it is determined in one of the two channels that the evaluation result created by the corresponding microcontroller indicates that the sensor signal of the flame sensor there does not correspond to a flame. Therefore, this embodiment provides the advantage that, according to the invention, diagnosing a channel indicates that a flame is no longer present, thereby causing an output signal indicating that a flame is not present. Therefore, within a predefined fault tolerance time, the fault tolerance time can be fully utilized, that is, the maximum possible number of repetitions of the comparison of the signal obtained from one of the two channels with the corresponding expected value according to the invention can be performed by means of two microcontrollers in a safer manner within the preset fault tolerance time, without causing flame elimination during the diagnostic time, because during the diagnostic period, the sensor signal of the channel notifying "flame presence" is used by the two microcontrollers as the basis for flame decision-making.

[0049] In a preferred embodiment of the invention, each of the two channels, and at least the analog portion of the two channels, is provided with a separate voltage supply device. This advantageously ensures the independence between the channels.

[0050] The present invention requires independent protection for the combustion chamber having a flame detector according to one embodiment of the above embodiments.

[0051] Although the effects and advantages of the embodiments described above according to the invention have been described in conjunction with a flame monitor according to the invention for monitoring at least one sub-region of a combustion chamber in terms of the presence of a flame, it should be understood that the effects and advantages described above also apply to the embodiments described below of the method according to the invention for monitoring at least one sub-region of a combustion chamber in terms of the presence of a flame, wherein, to avoid repetition, the effects and advantages will not be described in detail again. Preferred embodiments of the method according to the invention particularly include the following:

[0052] A preferred embodiment of the method according to the invention is characterized in that the fault continuation mode is initiated only when the result of the comparison by means of not only the first microcontroller but also the second microcontroller is: preferably, after taking into account tolerance deviations, the signal compared with the expected value deviates from the expected value.

[0053] An embodiment of the method according to the invention is characterized in that, when the result of the comparison by means of either the first microcontroller or the second microcontroller is preferably, after taking into account tolerance deviations, a fault continue operation mode is not initiated, but rather a fault stop is preferably triggered after, for example, a predetermined fault tolerance time of approximately 3 seconds.

[0054] An embodiment of the method according to the invention is characterized in that the signal obtained from one of the two channels is a signal obtained from the analog-to-digital converter in said one channel.

[0055] One embodiment of the method according to the invention includes a first analog switcher and a second analog switcher. The first analog switcher is disposed upstream of a first analog-to-digital converter in a first channel in an analog loop and can be switched by a diagnostic and comparison unit. The second analog switcher is disposed upstream of a second analog-to-digital converter in a second channel in an analog loop and can be switched by a diagnostic and comparison unit. By switching the first analog switcher and / or the second analog switcher, preferably limited to a predetermined test time period, a test signal for testing the analog-to-digital converter, preferably having a predetermined amplitude and / or a predetermined frequency, is delivered to the corresponding analog-to-digital converter in place of a sensor signal.

[0056] An embodiment of the method according to the present invention is characterized in that a first analog switcher can be switched by a first microcontroller via a first control line, a second analog switcher can be switched by a second microcontroller via a second control line, the state of the first control line can be monitored by the second microcontroller via a first readback line to the second microcontroller by comparing it with the desired state of the first control line, and the state of the second control line can be monitored by the first microcontroller via a second readback line to the first microcontroller by comparing it with the desired state of the second control line, and has the following steps: when the state of the first control line preferably deviates from the desired state of the first control line after considering tolerance deviation and / or the state of the second control line preferably deviates from the desired state of the second control line after considering tolerance deviation, a fault stop of the evaluation circuit is preferably triggered after a predetermined readback fault tolerance time.

[0057] An embodiment of the method according to the invention is characterized in that, after the end of a predetermined test period, the test signal in the first channel is disconnected by means of a first additional analog switch provided in the first channel and controllable by a diagnostic and comparison unit, and / or after the end of the predetermined test period, the test signal in the second channel is disconnected by means of a second additional analog switch provided in the second channel and controllable by a diagnostic and comparison unit.

[0058] An embodiment of the method according to the invention is characterized in that, after disconnecting the test signal in the selected channel and before turning on the sensor signal, two microcontrollers are used to check in the selected channel whether the test signal has been disconnected and whether the corresponding additional analog switch for disconnecting the test signal in the selected channel is functioning.

[0059] An embodiment of the method according to the invention is characterized in that the signal obtained from one of the two channels is a signal obtained from a relay in said one channel.

[0060] An embodiment of the method according to the present invention is characterized in that the signal obtained from the relay is a signal obtained from the readback contact of the relay.

[0061] An embodiment of the method according to the present invention is characterized in that a first relay can be controlled by a first microcontroller via a first relay control line, and a second relay preferably connected in series with the first relay can be controlled by a second microcontroller via a second relay control line. The state of the first relay control line can be monitored by the second microcontroller via a first relay readback line to the second microcontroller by comparing it with the desired state of the first relay control line, comprising the following steps: the state of the second relay control line is monitored by the first microcontroller via a second relay readback line to the first microcontroller by comparing it with the desired state of the second relay control line; and when the state of the first relay control line preferably deviates from the desired state of the first relay control line after considering tolerance and / or the state of the second relay control line preferably deviates from the desired state of the second relay control line after considering tolerance deviation, a fault stop of the evaluation circuit is preferably triggered after a predetermined readback fault tolerance time.

[0062] One embodiment of the method according to the invention includes a first amplifier disposed in an analog circuit and a second amplifier disposed in an analog circuit, the first amplifier being used to preprocess sensor signals in a first channel for use in a first analog-to-digital converter, and the second amplifier being used to preprocess sensor signals in a second channel for use in a second analog-to-digital converter, wherein the signal obtained from one of the two channels is the signal obtained from the amplifier in said one channel.

[0063] An embodiment of the method according to the present invention is characterized in that the first amplifier can be controlled by a first microcontroller via a first control line, and the second amplifier can be controlled by a second microcontroller via a second control line, comprising the following steps: the second microcontroller monitors the state of the first control line by comparing it with the desired state of the first control line via a first amplifier readback line to the second microcontroller; the first microcontroller monitors the state of the second control line by comparing it with the desired state of the second control line via a second amplifier readback line to the first microcontroller; and when the state of the first control line preferably deviates from the desired state of the first control line after considering tolerance deviation and / or the state of the second control line preferably deviates from the desired state of the second control line after considering tolerance deviation, a fault stop of the evaluation circuit is preferably triggered after a predetermined readback fault tolerance time.

[0064] An embodiment of the method according to the invention is characterized in that the comparison between the signal obtained from one of the two channels and the corresponding expected value is performed alternately by means of the signal obtained from the first channel and by means of the signal obtained from the second channel.

[0065] One embodiment of the method according to the invention is characterized by maintaining the fault-continuing operation mode for a predetermined period of time.

[0066] One embodiment of the method according to the invention is characterized in that the fault-continued operation mode includes: the evaluation circuit still operates in a single channel by means of only the other of the two channels.

[0067] An embodiment of the method according to the invention is characterized in that the evaluation circuit only operates by means of the other channel when the diagnostic and comparison unit classifies the other channel of the two channels as fault-free.

[0068] An embodiment of the method according to the invention is characterized in that, preferably only after a predetermined fault tolerance time has elapsed, the signal obtained from one of the two channels is compared multiple times with the corresponding expected value by means of both a first microcontroller and a second microcontroller, not only by means of a first microcontroller but also by means of a second microcontroller, before determining the result of the comparison.

[0069] An embodiment of the method according to the invention is characterized in that the comparison with the corresponding desired value is preferably performed solely by means of a signal obtained from a channel in which it is determined that the sensor signal generated by the flame sensor does not correspond to a flame.

[0070] Other embodiments of the present invention are described in the examples of the present invention. Attached Figure Description

[0071] Embodiments of the invention will now be described with reference to the accompanying drawings. Identical or functionally identical components are indicated by the same reference numerals. The drawings show:

[0072] Figure 1 A schematic construction of one embodiment of a combustion chamber with a flame detector is shown;

[0073] Figure 2 A schematic construction of a first embodiment of a flame detector is shown;

[0074] Figure 3 A schematic construction of a second embodiment of the flame detector is shown;

[0075] Figure 4 A schematic construction of a third embodiment of a flame detector is shown; and

[0076] Figure 5 A schematic construction of a fourth embodiment of a flame detector is shown. Detailed Implementation

[0077] Figure 1 A schematic construction of one embodiment of a combustion chamber 1 is shown, the combustion chamber having a flame monitor 2 for monitoring the presence of a flame 4 in the combustion chamber 1. The flame 4 is located in a burner (not shown) within the housing 6 of the combustion chamber 1, the burner being supplied with fuel via a fuel delivery device 8 connected to a fuel reserve (not shown) to feed the flame 4, and the burner also supplying air.

[0078] An observation tube 14 is provided in the opening 10 of the side wall 12 of the combustion chamber 1, shown on the right side, facing the flame detector 2, and is connected to the flame detector 2. The observation tube 14 is optional, so that the flame detector 2 can also be directly connected to the housing 6.

[0079] exist Figure 1 In the illustrated embodiment, the flame detector 2 has a flame sensor 16 on the section pointing towards the observation tube, the flame sensor being used to detect flames in the observation tube. Figure 1The physical variables of the flame 4 in the sub-region 18 for which the flame 4 is disposed, as shown by shaded lines, are particularly used for detecting electromagnetic radiation. For this purpose, the flame sensor 16 can observe the internal space 22 of the combustion chamber 1, surrounded by the housing 6, through the opening 10 with a conus or field of view 20 having an angle α of, for example, 6°. Furthermore, the flame sensor 16 is configured, particularly in its sensitivity, to generate a corresponding electrical sensor signal 26 (see [reference needed]) corresponding to the electromagnetic radiation 24 present in the sub-region 18 for which the flame 4 is disposed. Figure 2 ).exist Figure 1 In the illustrated embodiment, the flame sensor 16 is, for example, equipped with spectral sensitivity for detecting electromagnetic radiation in the wavelength range of approximately 280 nm to approximately 410 nm and / or approximately 190 nm to approximately 520 nm and / or approximately 780 nm to approximately 1800 nm.

[0080] Figure 2 Show flame monitor, for example according to Figure 1 A schematic construction of a first embodiment of a flame monitor 2. According to this embodiment, it is used to monitor the flame 4 in a combustion chamber, for example, according to... Figure 1 The flame detector 2 shown in the combustion chamber 1 has a flame sensor 16, which is used to detect, for example, according to... Figure 1 The physical variables of the flame in sub-region 18 are used to generate the associated electrical sensor signal 26.

[0081] exist Figure 2 The flame monitor 2 shown also has a dual-channel evaluation circuit 28 connected downstream of the flame sensor 16. The evaluation circuit is used to determine whether the sensor signal 26 generated by the flame sensor 16 corresponds to the flame 4, and to output an output signal EXTS1 indicating whether the flame 4 exists or not.

[0082] The dual-channel evaluation circuit 28 has a first channel 28-1 and a second channel 28-2 for processing sensor signals 26. In the analog circuit 30, the first channel 28-1 includes a first analog-to-digital converter 32 with a first analog amplifier, hereinafter referred to as the first AD converter 32. The first channel 28-1 also includes a first microcontroller 36 belonging to the digital diagnostic and comparison unit 34, which evaluates the first signal 38 obtained from the first AD converter 32. Furthermore, the first channel 28-1 includes a first relay 40 controlled by the first microcontroller 36 in the relay circuit 42.

[0083] In analog circuit 30, a second channel 28-2, preferably redundant with the first channel 28-1, has a second AD converter 44 with a second analog amplifier, a second microcontroller 46 belonging to digital diagnostics and comparison unit 34 for evaluating a second signal 48 obtained from the second AD converter 44, and a second relay 50 in relay circuit 42 controlled by the second microcontroller 46. Forced-guided relays are preferably used for relays 40 and 50, which are preferably connected in series such that if one relay 40 or 50 fails or is incorrectly activated, the other relay 40 or 50 is available.

[0084] Preferably, only one photoelectric sensor 16 is provided. The photoelectric sensor 16 is preferably configured as a photodiode. Preferably, the anode of the photodiode is guided to the first channel 28-1, and the cathode is guided to the second channel 28-2.

[0085] Preferably, in the event of a failure in one of the channels 28-1 or 28-2, the pin of the photoelectric sensor 16 or photodiode is placed at a fixed potential from the faulty channel 28-1 or 28-2 by means of an analog switch (not shown) to prevent a reaction from the faulty channel 28-1 or 28-2 to the other channel 28-1 or 28-2 via the photoelectric sensor 16.

[0086] The diagnostic and comparison unit 34 is configured to perform a comparison, indicated by double arrow 52, ​​on the first evaluation result of the first microcontroller 36 and the second evaluation result of the second microcontroller 46, and to influence the output signal EXTS1 based on the result of the comparison 52.

[0087] exist Figure 2 The diagnostic and comparison unit 34 of the embodiment shown is also configured to compare the signal obtained from one of the two channels 28-1 and 28-2 with the corresponding expected value, not only by means of the first microcontroller 36 but also by means of the second microcontroller 46, and optionally activate the fault continue operation mode by means of the evaluation circuit 28 based on the comparison result.

[0088] Therefore, the diagnostic and comparison unit 34 is preferably configured such that the fault continuation mode is activated only when the result of the comparison by means of not only the first microcontroller 36 but also the second microcontroller 46 is such that, preferably after taking into account the previously defined tolerance deviation, the signal compared with the expected value deviates from the expected value.

[0089] Preferably, the diagnostic and comparison unit 34 is configured such that when the result of the comparison by means of either the first microcontroller 36 or the second microcontroller 46 is such that, preferably after taking into account tolerance deviations, the signal compared with the expected value deviates from the expected value, the fault continue operation mode is not initiated, but rather the fault stop is triggered by the evaluation circuit 28 after a predefined fault tolerance time of approximately 3 seconds.

[0090] The signal obtained from one of the two channels 28-1 and 28-2 is preferably a signal obtained from the corresponding AD converter 32 or 44 in the corresponding channel 28-1 or 28-2. Alternatively, the signal obtained from one of the two channels 28-1 and 28-2 may additionally or alternatively be a signal obtained from the corresponding relay 40 or 50 in the corresponding channel 28-1 or 28-2.

[0091] The diagnostic and comparison unit 34 is preferably configured such that the comparison of the signal obtained from one of the two channels 28-1, 28-2 with the corresponding expected value can be performed alternately by means of the signal obtained from the first channel 28 and by means of the signal obtained from the second channel 28-2.

[0092] The diagnostic and comparison unit 34 is preferably configured such that it can maintain the fault-continuing operation mode for a predetermined period of time.

[0093] The fault-continuing operation mode of the evaluation circuit 28 preferably includes: the evaluation circuit 28 continues to operate single-channel only by means of the other channel of the two channels 28-1 or 28-2. More preferably, the evaluation circuit 28 continues to operate single-channel only by means of the other channel of the two channels 28-1 or 28-2 only when the diagnostic or comparison unit 34 classifies the other channel of the two channels 28-1 or 28-2 as fault-free.

[0094] The diagnostic and comparison unit 34 is preferably configured such that, prior to the evaluation circuit 28 determining the comparison result, preferably within a predetermined fault tolerance time, the diagnostic and comparison unit performs multiple comparisons of the signal obtained from one of the two channels 28-1, 28-2 with the corresponding expected value, not only by means of the first microcontroller 36 but also by means of the second microcontroller 46.

[0095] Furthermore, the diagnostic and comparison unit 34 is preferably configured such that if it is determined in one of the two channels 28-1, 28-2 that the sensor signal 26 generated by the flame sensor 16 does not correspond to the flame 4, the comparison with the corresponding expected value is preferably performed solely by means of the signals obtained from said channels 28-1, 28-2.

[0096] Preferably, for each of the two channels 28-1 and 28-2, at least for the analog portion of the two channels in the analog loop 30, there is a [missing information - likely a typo]. Figure 2 A separate voltage supply device is not shown in the diagram.

[0097] Figure 3 A schematic construction of a second embodiment of the flame detector 2' is shown. Figure 3 The flame detector 2' of the embodiment is constructed in its basic characteristics according to the method described above. Figure 2 The structure of flame detector 2. Additionally, in Figure 3 The flame monitor 2' shown in the embodiment has a first analog switch AS1 located upstream of the first AD converter 32 in the first channel 28-1 in the analog loop 30' and switchable by the diagnostic and comparison unit 34'. Furthermore, the flame monitor 2' has a second analog switch AS2 located upstream of the second AD converter 44 in the second channel 28-2 in the analog loop 30' and switchable by the diagnostic and comparison unit 34'.

[0098] exist Figure 3 The flame detector 2' of the embodiment shown also has a first amplifier V1 and a second amplifier V2 disposed in the analog circuit 30', the first amplifier being used to preprocess the sensor signal 26 in the first channel 28-1 for use in the first AD converter 32, and the second amplifier being used to preprocess the sensor signal 26 in the second channel 28-2 for use in the second AD converter 44.

[0099] In the first analog switch AS1 Figure 3 In the ON position shown, the first analog switch sends the sensor signal 26 as a first signal S1 preprocessed by amplifier V1 to the first AD converter 32. Similarly, in Figure 3 In the ON state shown, the second analog switch AS2 sends the sensor signal 26 as the second signal S2 processed by the amplifier V2 to the second AD converter 44.

[0100] exist Figure 3 The diagnostic and comparison unit 34' of the embodiment shown is configured to, by means of switching the first analog switch AS1 and / or by means of the second analog switch AS2, preferably limited to a predetermined test time period, replace the sensor signal 26, and transmit the test signal T1, preferably having a predetermined amplitude and / or a predetermined frequency, for testing the AD converter 32 or 44 to the corresponding AD converter 32 or 44.

[0101] The test signal T1 is preferably generated by one of the first microcontrollers 36, and more preferably only one test signal generator 60.

[0102] exist Figure 3 The diagnostic and comparison unit 34' of the embodiment shown is specifically configured to compare the signal D1 obtained from channel 28-1 with the corresponding expected value, preferably stored in a memory (not shown) of the diagnostic and comparison unit 34', not only by means of the first microcontroller 36 but also by means of the second microcontroller 46, and after the test signal T1 is correspondingly switched on to channel 28-1 by the analog switch AS1, the evaluation circuit 28' may optionally activate the fault continuation mode based on the comparison result.

[0103] exist Figure 3 The diagnostic and comparison unit 34' shown in the embodiment is also configured to compare the signal D2 obtained from the second channel 28-2 with the corresponding expected value, not only by means of the first microcontroller 36 but also by means of the second microcontroller 46, and, as long as the test signal T1 is connected to the AD converter 44 of the second channel 28-2 by means of the analog switch AS2 controlled by the diagnostic and comparison unit 34', the evaluation circuit 28' can optionally activate the fault continuation mode based on the comparison result. Figure 2 In the same implementation, the diagnostic and comparison unit 34' is configured such that the fault continuation mode is activated only when the result of the comparison by means of not only the first microcontroller 36 but also the second microcontroller 46 is such that, even after taking into account the previously defined tolerance deviation, the signal D1 compared with the expected value when testing the first channel 28-1 by means of the test signal T1 deviates from the expected value, or the signal D2 compared with the expected value when testing the second channel 28-2 by means of the test signal T1 deviates from the expected value.

[0104] The diagnostic and comparison unit 34' is preferably configured to compare the signal D1 or D2 obtained from one of the two channels 28-1 with the corresponding expected value, not only by means of the first microcontroller 36 but also by means of the second microcontroller 46, and optionally activate the fault continuation mode of the evaluation circuit 28' based on the result of the comparison, using the signal obtained from the corresponding amplifier V1 or V2 in the channel 28-1 or 28-2 as a signal.

[0105] Therefore, in the described embodiment, one of the two channels 28-1 or 28-2 is diagnosed using a separate test signal T1. According to the invention, the corresponding AD converter 32 or 44 is tested or diagnosed using the test signal T1. Thus, it can be determined that either the analog portion of channel 28-1 or 28-2—that is, the analog portion of channel 28-1 consisting of the first amplifier V1 and the first AD converter 32, or the analog portion of channel 28-2 consisting of the second amplifier V2 and the second AD converter 44—is fault-free if the signal D1 or D2 obtained from the corresponding AD converter 32 or 44 corresponds to the desired value, or the obtained signal D1 or D2, even after deducting the corresponding tolerance deviation, does not correspond to the desired value, not only by means of the first microcontroller 36 but also by means of the second microcontroller 46, can be used to initiate a fault-continued operation mode via evaluation circuit 28'. The desired value here can be a specific test mode. The expected value or test mode is preferably exchanged via internal data exchange between the two microcontrollers 36 or 46 according to arrow 52, ​​so that the two microcontrollers 36 and 46 have the same expected value or the same test mode.

[0106] As in Figure 2 As in the implementation, the fault-continuing operation mode of the evaluation circuit 28' in a preferred variant also includes: the evaluation circuit 28' still operating single-channel only by means of the other channel of the two channels 28-1 or 28-2. More preferably, the evaluation circuit 28' only continues to operate single-channel only by means of said other channel of the two channels 28-1 or 28-2 when the diagnostic or comparison unit 34' classifies the other channel of the two channels 28-1 or 28-2 as fault-free. Alternatively, it is preferred that only the analog portion of the corresponding channel 28-1 or 28-2 is single-channel, while the data evaluation of the actual signal S1 or S2 in the diagnostic and evaluation unit 34' continues to be performed by two microcontrollers 36 and 46, wherein the signal D1 or D2, as in Figure 3 As shown in the diagram, they are correspondingly directed to the two microcontrollers 36 and 46.

[0107] Preferably, for the stated purpose, the first amplifier V1 can be controlled by the first microcontroller 36 via a first control line (not shown), and the second amplifier V2 can be controlled by the second microcontroller 46 via a second control line (not shown). The state of the first control line can be monitored by the second microcontroller 46 via a first amplifier readback line (not shown) to the second microcontroller 46 by comparing it with the desired state of the first control line. The state of the second control line can be monitored by the first microcontroller via a second amplifier readback line (not shown) to the first microcontroller by comparing it with the desired state of the second control line. Furthermore, when the state of the first control line preferably deviates from the desired state of the first control line after considering tolerance deviations and / or the state of the second control line preferably deviates from the desired state of the second control line after considering tolerance deviations, a fault stop is preferably triggered by an evaluation circuit or a corresponding output signal indicating the absence of flame is output after, for example, approximately 3 seconds of a predetermined readback fault tolerance time.

[0108] Figure 4 A schematic construction of a third embodiment of the flame detector 2” is shown. Figure 4 The basic structure of the flame detector 2 in the implementation method basically corresponds to that based on Figure 3 The second embodiment of the flame detector 2' is constructed as follows. For simplicity, in Figure 4 The displays for A / D converters 32 and 44 are omitted.

[0109] exist Figure 4 In a third embodiment of the flame detector 2, the first analog switcher AS1 can be switched by the first microcontroller 36 via the first control line SAS1. The second analog switcher AS2 can be switched by the second microcontroller 46 via the second control line SAS2. The state of the first control line SAS1 can be monitored by the second microcontroller 46 via the first readback line RAS1 to the second microcontroller 46 by comparing it with the desired state of the first control line. The state of the second control line SAS2 can be monitored by the first microcontroller 36 via the second readback line RAS2 to the first microcontroller 36 by comparing it with the desired state of the second control line.

[0110] According to Figure 4In the flame monitor 2” of the third embodiment, when the state of the first control line SAS1 preferably deviates from the desired state of the first control line after considering tolerance deviation and / or the state of the second control line preferably deviates from the desired state of the second control line after considering tolerance deviation, preferably after a predetermined fault readback tolerance time of, for example, about 3 seconds, the evaluation circuit 28” triggers fault stop or generates and outputs an output signal EXTS1 indicating that the flame does not exist.

[0111] Preferably, a first additional analog switch (not shown) controllable by the diagnostic and comparison unit 34” is provided in the first channel 28-1. The first additional analog switch is used to disconnect according to... Figure 3 The test signal T1 is provided, and a second additional analog switch, also not shown, is provided in the second channel 28-2, which can be controlled by the diagnostic and comparison unit 34” to disconnect the test signal T1. Here, the diagnostic and comparison unit 34” is preferably configured such that after disconnecting the test signal T1 in the selected channel 28-1 or 28-2 and before turning on the sensor signal 26, the diagnostic and comparison unit checks, by means of two microcontrollers 36 and 46, in the corresponding selected channel 28-1 or 28-2 whether the test signal T1 is disconnected and whether the corresponding additional analog switch in the selected channel 28-1 or 28-2 for disconnecting the test signal T1 is functioning.

[0112] Figure 5 A fourth embodiment of the flame detector 2”' according to the present invention is shown. Figure 5 The flame detector 2”’ shown in the fourth embodiment is substantially corresponding in its basic construction to Figure 2 The first embodiment of the flame detector 2. However, flame detector 2"' may also correspond to one of the flame detectors 2' or 2" or may be a combination of all the embodiments described above. In addition, for simplicity, in Figure 5 The diagram only shows the diagnostic and comparison unit 34”' and the relay circuit 42”'. Figure 5In the embodiment shown, the signal obtained from the corresponding relay 40 or 50 is signal FB1 or FB2 obtained from the readback contact of the corresponding relay 40 or 50. Correspondingly, the diagnostic and comparison unit 34”' in this embodiment is configured to compare the signal FB1 or FB2 obtained from one of the two channels 28-1 or 28-2 via the readback contact of the corresponding relay 40 or 50 with the corresponding expected value. This is achieved not only by means of the first microcontroller 36 but also by means of the second microcontroller 46. Similarly, in this embodiment, the diagnostic and comparison unit 34”' is also configured to optionally activate the fault continuation operation mode of the evaluation circuits 28, 28', 28” based on the comparison result.

[0113] The diagnostic and comparison unit 34"' is preferably configured such that the fault continuation mode is initiated only when the result of the comparison by means of both the first microcontroller 36 and the second microcontroller 46 is such that, preferably after considering tolerance deviations, the signal FB1 or FB2 compared with the expected value deviates from the expected value. The diagnostic and comparison unit 34"' is preferably configured such that, when the result of the comparison by means of either the first microcontroller 36 or the second microcontroller 46 is such that, preferably after considering tolerance deviations, the signal FB1 or FB2 compared with the expected value deviates from the expected value, the fault continuation mode is not initiated, but rather the fault stop of the evaluation circuits 28, 28', 28" is triggered preferably after, for example, a predetermined fault tolerance time of approximately 3 seconds.

[0114] Figure 5 The fourth embodiment further illustrates that the first relay 40 can be controlled by the first microcontroller 36 via the first relay control line C1. Similarly, the second relay 50, preferably connected in series with the first relay 40, can be controlled by the second microcontroller 46 via the second relay control line C2.

[0115] Relatedly, in Figure 5 In the fourth embodiment of the flame detector 2”' shown, the state of the first relay control line C1 can be monitored by the second microcontroller 46 via the first relay readback line CCR1 to the second microcontroller 36 by comparing it with the desired state of the first relay control line. Furthermore, the state of the second relay control line C2 can be monitored by the first microcontroller 36 via the second relay readback line CCR2 to the first microcontroller 36 by comparing it with the desired state of the second relay control line. In the flame detector 2”' according to the invention... Figure 5In the fourth embodiment shown, when the state of the first relay control line C1 preferably deviates from the desired state of the first relay control line after considering tolerance deviation and / or the state of the second relay control line C2 preferably deviates from the desired state of the second relay control line after considering tolerance deviation, the fault stop is preferably triggered by the evaluation circuit 28 after a predetermined fault tolerance time.

Claims

1. A flame monitor (2, 2', 2'', 2'''), said flame monitor for monitoring at least one sub-region (18) of a combustion chamber (1) in relation to the presence of a flame (4), said flame monitor having: A flame sensor (16) is used to detect physical variables of the flame (4) and to generate an associated electrical sensor signal (26). A dual-channel evaluation circuit (28, 28', 28'') is connected downstream of the flame sensor (16). The dual-channel evaluation circuit is used to determine whether the sensor signal (26) generated by the flame sensor (16) corresponds to the flame (4), and to output an output signal (EXTS1) indicating whether the flame (4) is present or not in a safety-oriented manner. The dual-channel evaluation circuit (28, 28', 28'') has the following characteristics: A first channel (28-1) is established for processing the sensor signal (26), the first channel comprising: The analog circuit (30) includes a first analog-to-digital converter (32); a first microcontroller (36) belonging to a digital diagnostic and comparison unit (34, 34', 34'', 34'''), the first microcontroller being used to evaluate a first signal obtained from the first analog-to-digital converter (32); and a first relay (40) in a relay circuit (42, 42''') controlled by the first microcontroller (36). A second channel (28-2) for processing the sensor signal (26) is established, the second channel comprising: a second analog-to-digital converter (44) in the analog circuit (30); a second microcontroller (46) belonging to the digital diagnostic and comparison unit (34, 34', 34'', 34'''), the second microcontroller being used to evaluate the second signal obtained from the second analog-to-digital converter (44); and a second relay (50) in the relay circuit (42, 42"') controlled by the second microcontroller (46). The diagnostic and comparison units (34, 34', 34'', 34''') are configured to perform a comparison between a first evaluation result of the first microcontroller (36) and a second evaluation result of the second microcontroller (46), and to influence the output signal (EXTS1) based on the result of the comparison. Its features are, The diagnostic and comparison units (34, 34', 34'', 34''') are configured for, The signal obtained from one of the two channels is compared with the corresponding expected value not only by means of the first microcontroller (36) but also by means of the second microcontroller (46), and Based on the results of the comparison, the fault continuation operation mode of the evaluation circuit (28, 28', 28'') is activated.

2. The flame detector (2, 2', 2'', 2''') according to claim 1. The physical variable of the flame (4) is the intensity of electromagnetic radiation.

3. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The diagnostic and comparison units (34, 34', 34'', 34''') are configured such that the fault continue operation mode is activated only when the result of the comparison by means of the first microcontroller (36) and the second microcontroller (46) is that the signal compared with the expected value deviates from the expected value.

4. The flame detector (2, 2', 2'', 2''') according to claim 3. The diagnostic and comparison units (34, 34', 34'', 34''') are configured such that the fault continue operation mode is activated only when the result of the comparison by means of the first microcontroller (36) and the second microcontroller (46) is that, after taking into account tolerance deviations, the signal compared with the expected value deviates from the expected value.

5. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The diagnostic and comparison units (34, 34', 34'', 34''') are configured such that when the result of the comparison, either by means of the first microcontroller (36) or by means of the second microcontroller (46), is that the signal compared with the expected value deviates from the expected value, the fault continue operation mode is not initiated, but the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

6. The flame detector (2, 2', 2'', 2''') according to claim 5. The diagnostic and comparison units (34, 34', 34'', 34''') are configured such that, when the result of the comparison, either by means of the first microcontroller (36) or by means of the second microcontroller (46), is that the signal compared to the expected value deviates from the expected value after taking into account tolerance deviation, the fault continue operation mode is not initiated, but the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

7. The flame detector (2, 2', 2'', 2''') according to claim 5. The evaluation circuit (28, 28', 28'') is triggered to stop faulting after a predefined fault tolerance time.

8. The flame detector (2, 2', 2'', 2''') according to claim 7. The predetermined fault tolerance time is 3 seconds.

9. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The signal obtained from one of the two channels is the signal obtained from the analog-to-digital converter in said channel.

10. The flame detector (2, 2', 2'', 2''') according to claim 9. The flame monitor has a first analog switch (AS1) located upstream of the first analog-to-digital converter in the first channel (28-1) of the analog circuit (30) and switchable by the diagnostic and comparison unit (34, 34', 34'', 34'''). The flame monitor also has a second analog switch (AS2) located upstream of the second analog-to-digital converter in the second channel (28-2) of the analog circuit (30) and switchable by the diagnostic and comparison unit (34, 34', 34'', 34'''). The diagnostic and comparison units (34, 34', 34'', 34''') are configured to, by means of switching the first analog switch and / or the second analog switch (AS2), replace the sensor signal (26) to deliver a test signal (T1) for testing the analog-to-digital converter to the corresponding analog-to-digital converter.

11. The flame detector (2, 2', 2'', 2''') according to claim 10. The diagnostic and comparison units (34, 34', 34'', 34''') are configured to, by means of switching the first analog switch and / or the second analog switch (AS2), within a predefined test time period, replace the sensor signal (26) and transmit a test signal (T1) for testing the analog-to-digital converter to the corresponding analog-to-digital converter.

12. The flame detector (2, 2', 2'', 2''') according to claim 10. The test signal (T1) mentioned therein is a test signal (T1) with a predetermined amplitude and / or a predetermined frequency.

13. The flame detector (2, 2', 2'', 2''') according to claim 10, wherein The first analog switch (AS1) can be switched by the first microcontroller (36) via the first control line (SAS1). The second analog switch (AS2) can be switched by the second microcontroller (46) via the second control line (SAS2). The state of the first control line (SAS1) can be monitored by the second microcontroller (46) via the first readback line (RAS1) by comparing it with the desired state of the first control line. The state of the second control line (SAS2) can be monitored by the first microcontroller (36) via the second readback line (RAS2) to the first microcontroller (36) by comparing it with the desired state of the second control line, and in, When the state of the first control line (SAS1) deviates from the expected state of the first control line and / or the state of the second control line (SAS2) deviates from the expected state of the second control line, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

14. The flame detector (2, 2', 2'', 2''') according to claim 13. in, When the state of the first control circuit (SAS1) deviates from the expected state of the first control circuit after considering tolerance deviations and / or the state of the second control circuit (SAS2) deviates from the expected state of the second control circuit, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

15. The flame detector (2, 2', 2'', 2''') according to claim 13. in, When the state of the first control circuit (SAS1) deviates from the expected state of the first control circuit and / or the state of the second control circuit (SAS2) deviates from the expected state of the second control circuit after considering tolerance deviations, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

16. The flame detector (2, 2', 2'', 2''') according to claim 13. The fault stop of the evaluation circuit (28, 28', 28'') is triggered after a predefined readback fault tolerance time.

17. The flame detector (2, 2', 2'', 2''') according to claim 10. The first channel (28-1) is provided with a first additional analog switch that can be controlled by the diagnostic and comparison unit (34, 34', 34''), the first additional analog switch being used to disconnect the test signal (T1) in the first channel (28-1), and the second channel (28-2) is provided with a second additional analog switch that can be controlled by the diagnostic and comparison unit (34, 34', 34'', 34'''), the second additional analog switch being used to disconnect the test signal (T1) in the second channel (28-2).

18. The flame detector (2, 2', 2'', 2''') according to claim 17. The diagnostic and comparison units (34, 34', 34'', 34''') are configured to, by means of two microcontrollers, check in the selected channel whether the test signal (T1) is disconnected and whether the corresponding additional analog switch for disconnecting the test signal in the selected channel is functioning after the test signal (T1) in the selected channel is disconnected and before the sensor signal (26) is turned on.

19. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The signal obtained from one of the two channels is a signal obtained from the relay in the one channel (FB1, FB2).

20. The flame detector (2, 2', 2'', 2''') according to claim 19. The signals obtained from the relay are signals obtained from the readback contacts of the relay (FB1, FB2).

21. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2, wherein The first relay (40) can be controlled by the first microcontroller (36) via the first relay control circuit (C1). The second relay (50) can be controlled by the second microcontroller (46) via the second relay control circuit (C2). The state of the first relay control line (C1) can be monitored by the second microcontroller (46) via the first relay readback line (CCR1) by comparing it with the desired state of the first relay control line. The state of the second relay control circuit (C2) can be monitored by the first microcontroller (36) via the second relay readback circuit (CCR2) to the first microcontroller (36) by comparing it with the desired state of the second relay control circuit, and in, When the state of the first relay control circuit (C1) deviates from the expected state of the first relay control circuit and / or the state of the second relay control circuit (C2) deviates from the expected state of the second relay control circuit, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

22. The flame detector (2, 2', 2'', 2''') according to claim 21. The second relay (50) is connected in series with the first relay (40).

23. The flame detector (2, 2', 2'', 2''') according to claim 21. in, When the state of the first relay control circuit (C1) deviates from the expected state of the first relay control circuit after considering tolerance deviations and / or the state of the second relay control circuit (C2) deviates from the expected state of the second relay control circuit, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

24. The flame detector (2, 2', 2'', 2''') according to claim 21. in, When the state of the first relay control circuit (C1) deviates from the expected state of the first relay control circuit and / or the state of the second relay control circuit (C2) deviates from the expected state of the second relay control circuit after considering tolerance deviations, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

25. The flame detector (2, 2', 2'', 2''') according to claim 21. The fault stop of the evaluation circuit (28, 28', 28'') is triggered after a predefined readback fault tolerance time.

26. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The flame monitor has a first amplifier (V1) disposed in the analog circuit (30), the first amplifier being used to preprocess the sensor signal (26) in the first channel (28-1) for use in the first analog-to-digital converter (32), and The flame monitor has a second amplifier (V2) disposed in the analog circuit (30), the second amplifier being used to preprocess the sensor signal (26) in the second channel (28-2) for use in the second analog-to-digital converter (44). The signal obtained from one of the two channels is the signal obtained from the amplifier in the one channel (S1, S2).

27. The flame detector (2, 2', 2'', 2''') according to claim 26, wherein The first amplifier (V1) can be controlled by the first microcontroller (36) via the first control circuit. The second amplifier (V2) can be controlled by the second microcontroller (46) via the second control circuit. The state of the first control line can be monitored by the second microcontroller (46) via a first amplifier readback line by comparing it with the desired state of the first control line. The state of the second control line can be monitored by the first microcontroller (36) via a second amplifier readback line to the first microcontroller (36) by comparing it with the desired state of the second control line, and in, When the state of the first control circuit deviates from the desired state of the first control circuit and / or the state of the second control circuit deviates from the desired state of the second control circuit, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

28. The flame detector (2, 2', 2'', 2''') according to claim 27. in, When the state of the first control circuit deviates from the expected state of the first control circuit after considering tolerance deviations and / or the state of the second control circuit deviates from the expected state of the second control circuit, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

29. The flame detector (2, 2', 2'', 2''') according to claim 27. in, When the state of the first control circuit deviates from the desired state of the first control circuit and / or the state of the second control circuit deviates from the desired state of the second control circuit after considering tolerance deviation, the fault stop of the evaluation circuit (28, 28', 28'') is triggered.

30. The flame detector (2, 2', 2'', 2''') according to claim 27. The fault stop of the evaluation circuit (28, 28', 28'') is triggered after a predefined readback fault tolerance time.

31. The flame detector (2, 2', 2'', 2''') according to claim 30. The predefined readback fault tolerance time is 3 seconds.

32. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The diagnostic and comparison units (34, 34', 34'', 34"') are configured such that the comparison of a signal obtained from one of the two channels with the corresponding expected value can be performed alternately by means of the signal (D1) obtained from the first channel (28-1) and by means of the signal (D2) obtained from the second channel (28-2).

33. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The diagnostic and comparison units (34, 34', 34'', 34''') are configured to maintain the fault-continuing operation mode for a predetermined period of time.

34. The flame detector (2, 2', 2'', 2''') according to claim 33. The diagnostic and comparison units (34, 34', 34'', 34''') are configured to maintain the fault-continued operation mode for a period of 24 hours.

35. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The fault-tolerant operation modes include: The evaluation circuit (28, 28', 28'') still operates in a single-channel manner only by means of another of the two channels, or the fault-continuing operation mode includes: only the analog portion of the corresponding channel is single-channel, while the data evaluation of the real signals (S1, S2) in the diagnostic and evaluation unit (34') continues to be performed by two microcontrollers, wherein the signals from the aforementioned analog portions of the corresponding channels are directed to the two microcontrollers for evaluation.

36. The flame detector (2, 2', 2'', 2''') according to claim 35. The analog portion of the respective channel includes amplifiers (V1, V2) and AD converters (32, 44).

37. The flame detector (2, 2', 2'', 2''') according to claim 35. The evaluation circuit (28, 28', 28'') only operates single-channel by means of the other channel when the diagnostic and comparison unit (34, 34', 34'', 34''') classifies the other of the two channels as fault-free.

38. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The diagnostic and comparison units (34, 34', 34'', 34''') are configured to compare the signal obtained from one of the two channels with the corresponding expected value multiple times, not only by means of the first microcontroller (36) but also by means of the second microcontroller (46), before determining the result of the comparison.

39. The flame detector (2, 2', 2'', 2''') according to claim 38. The diagnostic and comparison unit (34, 34', 34'', 34''') is configured to, before determining the result of the comparison, within a predetermined fault tolerance time of 1s to 10s, compare the signal obtained from one of the two channels with the corresponding expected value multiple times, not only by means of the first microcontroller (36) but also by means of the second microcontroller (46).

40. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. The diagnostic and comparison units (34, 34', 34'', 34''') are configured to perform a comparison with the corresponding expected value by means of a signal obtained from the channel if it is determined in one of the two channels that the sensor signal (26) generated by the flame sensor (16) does not correspond to the flame (4).

41. The flame detector (2, 2', 2'', 2''') according to claim 40. The comparison with the corresponding expected value is performed solely by means of the signal obtained from the channel.

42. The flame detector (2, 2', 2'', 2''') according to claim 1 or 2. Each of the two channels, and at least the analog portion of the two channels, is provided with a separate voltage supply device.

43. A combustion chamber (1) having a flame detector (2, 2', 2'', 2''') according to any one of claims 1 to 42.

44. A method for monitoring at least one sub-region (18) of a combustion chamber (1) in relation to the presence of a flame (4), the method comprising the steps of: The physical variables of the flame (4) are detected by means of a flame sensor (16), and the corresponding electrical sensor signal (26) is generated. The evaluation circuit (28, 28', 28'') connected downstream of the flame sensor (16) determines whether the sensor signal (26) generated by the flame sensor (16) corresponds to the flame (4), and outputs an output signal (EXTS1) indicating whether the flame (4) is present or not in a safety-oriented manner. In the first channel (28-1) of the evaluation circuit (28, 28', 28''), the sensor signal (26) is processed by means of a first analog-to-digital converter (32) in the analog circuit (30), a first microcontroller (36) belonging to the digital diagnostic and comparison unit (34, 34', 34'', 34''') for evaluating the first signal obtained from the first analog-to-digital converter (32), and a first relay controlled by the first microcontroller (36) in the relay circuit. In the second channel (28-2) of the evaluation circuit (28, 28', 28''), the sensor signal (26) is processed by means of a second analog-to-digital converter (44) in the analog circuit (30), a second microcontroller (46) belonging to the digital diagnostic and comparison unit (34, 34', 34'', 34''') for evaluating the second signal obtained from the second analog-to-digital converter (44), and a second relay (50) controlled by the second microcontroller (46) in the relay circuit (42, 42'''). The first evaluation result of the first microcontroller (36) and the second evaluation result of the second microcontroller (46) are compared, and the output signal (EXTS1) is affected according to the result of the comparison. Its features are, The signal obtained from one of the two channels is compared with the corresponding expected value not only by means of the first microcontroller (36) but also by means of the second microcontroller (46), and Based on the results of the comparison, the fault continuation operation mode of the evaluation circuit (28, 28', 28'') is activated.

45. The method of claim 44, wherein the method is a method for monitoring at least one sub-region (18) of the combustion chamber (1) in terms of the presence of flame (4) in the combustion chamber (1) of claim 43.

46. ​​The method according to claim 44, The physical variable of the flame (4) is the intensity of electromagnetic radiation.

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