Flame monitor

Abstract

The invention relates to a flame monitor (2, 2′, 2″, 2′″) for monitoring at least one sub-region (18) of a combustion chamber (1) for the presence of a flame (4), comprising: a flame sensor (16) for sensing a physical variable of a flame (4), in particular an intensity of electromagnetic radiation, and for generating an associated electrical sensor signal (26), a dual-channel analyser circuit (28, 28′, 28″), connected downstream from the flame sensor (16), for determining whether the sensor signal (26) generated by the flame sensor (16) corresponds to a flame (4) and for outputting a safety-oriented output signal (EXTS1) indicating the presence or absence of a flame (4), wherein the dual-channel analyser circuit (28, 28′, 28″) comprises: a first channel (28-1) configured to process the sensor signal (26), said channel comprising a first analogue-digital converter (32) in an analogue circuit (30), a first microcontroller (36) belonging to a digital diagnostic comparator unit (34, 34′, 34″, 34′″), for analysing a first signal obtained from the first analogue-digital converter (32), and a first relay (40) in a relay circuit (42, 42″), which relay (40) is controlled by the first microcontroller (36), and a second channel (28-2) configured to process the sensor signal (26), said channel comprising a second analogue-digital converter (44) in the analogue circuit (30), a second microcontroller (46) belonging to the digital diagnostic comparator unit (34, 34′, 34″, 34′″), for analysing a second signal obtained from the second analogue-digital converter (44), and a second relay (50) in the relay circuit (42, 42″), which relay (50) is controlled by the second microcontroller (46), wherein the diagnostic comparator unit (34, 34′, 34″, 34′″) is configured to compare a first result of analysis from the first microcontroller (36) and a second result of analysis from the second microcontroller (46) and to influence the output signal (EXTS1), depending on the result of the comparison, characterised in that the diagnostic comparator unit (34, 34′, 34″, 34′″) is configured to compare a signal (D1, D2; FB1, FB2) obtained from one of the two channels (28-1, 28-2) with an associated expected value, with the aid of both the first microcontroller (36) and the second microcontroller (46), and optionally to initiate a fail-operational mode of the analyser circuit (28, 28′, 28″) depending on the result of the comparison.

Dependencies are inferred from the claim text.