c250-S: FB reports wiring error after switching on

Question?

When starting my safety program, the SF-Antivalent FB always signals that the connected sensor is actuated and there is an error. Do I have to pay special attention to the FB?

Answer:

If a TRUE is present at the start of the safety-I/O-module at the 'S_Channel1NC'-input and a FALSE at the ,S_Channel1NO'-input, the error code 49154 (16#C002) is displayed. The TRUE level at the NC input is only recognized correctly after the first signal change.

Workaround 1: Do not activate the SF_Antivalent FB until FSoE is running, e.g. by evaluating the S_InReady output of the FSoEMaster FB.

Workaround 2: Set the tolerated discrepancy time greater than the start time of the safety system (if this is acceptable in terms of safety).