ASSEMBLY CONSISTING OF A FAIL-SAFE SWITCHING DEVICE AND A DEVICE FOR AUTOMATICALLY TESTING THE FUNCTIONAL ABILITY OF THE FAIL-SAFE SWITCHING DEVICE

摘要

The invention relates to an assembly consisting of a fail-safe switching device, which is used to trip the operation of a consumer in a potentially dangerous situation or as a safety precaution in accordance with a trip signal of a monitoring device and of a device for automatically testing the functional ability of the fail-safe switching device. The aim of the invention is to also enable said test to be carried out during the operation of the consumer. To achieve this: the fail-safe switching device comprises two controllable switching circuits (106, 107; 108, 109), whose output terminals are interconnected to form the output (A7) of the fail-safe switching device; a first test switching pulse (SP4) can be fed to the first switching circuit (106, 107) in a cyclic manner and a second test switching pulse (SP5), which is staggered in relation to the first, can be fed to the other switching circuit (108, 109) in a cyclic manner; the switching circuits are designed in such a way that the output voltage (PK, PP) of the fail-safe switching device fluctuates upon receipt of the staggered test switching pulses by an amplitude that deviates from the amplitude of the output voltage upon receipt of simultaneous test switching pulses; and that the fail-safe device triggers the tripping of the consumer upon receipt of simultaneous test switching pulses.