Best way to know the operating status of the CPUs of a redundant system

Hi experts!

I would like to know what is the best way to know the operating status of the CPUs of a redundant system (417H).  The objective is to know if the CPU that is waiting goes to the stop state.  Right now the way it is being used is to visualize the LEDs.  Surely there is an optimal way to do it.  Can SFC51 be used in some way or should OBs 70-72 be implemented?

Thanks un advance!

Closed cause question posted twice.

The second thread with the subject best way to know the operating status of a redundant PLC system is published within the conference STEP 7 / STEP 7 Lite.