Safety system for a plant comprising a test signal path with return path

摘要

The system has a termination element (32) which is provided to connect a forward path (38) to a return path (40) of a test signal path (36). A safety unit (10) is provided to transmit an output signal at an output connected to the forward path. The termination element is comprised to receive output signal from forward path and to output a test signal to return path of test signal path. The test signal is changed based on the received output signal in dependence on the output signal received from forward path.