Siemens Failsafe Signal Modules

For the first time I'm working with the failsafe safety modules and one little thing is annoying me in that there appears to be no information.

When you assign the addresses to the cards, there is always an output area associated with the input cards and vice versa for the output cards.

When you click in hardware profile to edit the symbols, only the inputs turn up.

I cannot see where you would use the outputs, reading the manuals they only mention the outputs in the tech specs stating how much of an allocation.

Anyone know;

Why they allocate outputs?

and How and why do you use them?

Peter

Im sure I have some detailed info
but the short of it is that it is your F safety process image

You will need to monitor the "pass_out", "qbad" etc

The Safety integrated system uses the extra I/O address space for the send/receive of a CRC based telegram. Each end monitors the telegram and if a problem is encountered, the plc can report it and the safety outputs can go to their fail safe state.

Thanks, mystery solved.

Wish they state that in plain site, had me wondering if there was supposed to be something important I should be doing with it.

Then I stand corrected
I didnt know CRC data from the message frame is there

I was looking at this

More detail

CRC data with process image

I had a peep at the contents of the safety blocks to see what was going on