Method and circuit arrangement for continuous fail-safe testing of an infrared sensor device

摘要

Method for continuous fail-safe testing of an infrared sensor device of an alarm transmitter. The analog output signals of the infrared sensor device, for example the fundamental signals which always occur even in the absence of a dangerous situation and are caused to the thermal currents of the surrounding air, are highly amplified and converted into digital signals by level limitation. The temporal occurrence of these digital signals is monitored, it being assumed, when during a certain time interval no digital signals occur, that the infrared sensor device is faulty. In this case, a corresponding fault alarm is triggered.