"Splitting" an SSI input ?

I have an application where I need a single SSI encoder to connect to both a safety controller (SICK Flexi Soft) and a general-purpose PLC (S7-1500 with ET200SP I/O).

The safety vendor can set up their input modules as either an SSI master or SSI "listener".

They suggest that I might be able to connect the ET200SP module as an SSI Master and connect the Flexi Soft as an SSI "listener".

Has anyone done that ? I am not familiar with "splitting" SSI signals.

It is my understanding that anything connected to a safety system has to be "owned" by the safety system. If someone else needs the signal, you can re-transmit, spit etc.. but the power and control must come from the fail safe system.

Will the Flexi Soft listen to the clock signal generated by the ET200SP and the data at the same time?

Our product will be a listener or monitor as we call it. This allows several RMCs to by synchronized to one encoder without communication delays.

This doesn't help you though except for to know it has been done.

The FlexiSoft user manual describes the input signals levels for the Clock and the Data lines when operating in "SSI Listener" mode, and then separately describes the output signal for the Clock when acting in "SSI Master" mode. SICK has verified that the Flexi Soft can act as a "Listener" and still perform its safety functions for speed mismatch and overspeed.

The Siemens module is an ET200SP "Technology Module TM PosInput 1", p/n 6ES7138-6BA00-0BA0.

It only shows the Clock and Data connections and doesn't mention "Master" or "Listener" modes.

Because SSI is electrically RS-422, it makes sense that I can connect it in a "multi-drop" configuration as long as the "Listener" device doesn't attempt to control the Clock signal.

It may be that this just can't go forward until I test it.

Thanks, Peter, for the vote of confidence in the feasibility of such a connection.