Question:
Are there any normative specifications which must be observed when configuring the AIS input at SM301, SM302 or extended safety?
Answer:
The AIS input (Acknowledge In Start) is used to acknowledge the manual restart after STO / SS1 or SS2 / SOS via a single-channel hardware input.
Since (re-) start acknowledgements are relevant to safety, but the input is only designed as a single-channel input, the safety components evaluate both the rising and the falling edge. Between the edges, there must be a time interval of 0.3 s to 10 s. If the AIS input is to be controlled via a standard machine component (e. g. digital output of the controller or I/O system), the customer must ensure that the (re-) start will not be unexpectedly automatically acknowledged incorrectly as a result of an error in the standard component (e. g. toggling of the output).
In chapter 9.2.5.4.2, DIN EN 60204-1:2006 explicitly states that systems must only be manually restarted after an emergency stop.
