I wrote:
Is your opto isolation truly opto-isolated i.e. can you ground either wire without any bad effect?. If not, you are NOT opto-isolated, just "using opto-isolators".

I should have been clear and said:
Is your opto isolation truly opto-isolated i.e. can you ground either wire without any bad effect?. If not, you are NOT opto-isolated with respect to cable noise pickup, just "using opto-isolators to avoid ground loops, which, of course is beneficial". If the two signal lines float you have the equivalent of a differential transmission which is the most noise immune signal you can have.


Above it is mentioned that your encoder may have A+ and A- outputs. In that case Use those two as differential signals from the encoder to the uC and you can do single level opto-isolation.

Erik

Erik







Erik