Hi Richy,

As far as I remember the principlle of AS-I safety is the exchange of data telegrams between the monitor and the safety slaves, so that is the reason why you see these changes. As long as these changes go on, the slave is still in its working state.

You also have to take notice of the fact that this communication takes place over several inputs and outputs, two inputs and two outputs if I'm correct.

If you detect a zero (null) on these inputs at the same time than the slave is no longer in its safe state, e.g. emergency stop is pushed.

I found some documentation in my collection, see attachment. I haven't read it in a while, but I think the working principle is in it. If not, please let me know.

I found a sample program: Micro Automation: Safety-integrated switching in the AS-interface network (MAS 7)