If you are using a servo for the spindle with the CSMIO/IP-A you need to feed the encoder back to the IP-A so that it can close the loop to the spindle. In addition you also need to have feedback going to the Enc module if you want rigid tapping. You can do that with a separate encoder as in the diagram or you can also just feed the encoder to both the IP-A and the Enc. That is the way I have it on the Chiron and it works fine. Only thing that may be an issue is if you have the spindle geared, in that case it may be required that you have a separate encoder for the spindle, I will find that out soon as I have plans to increase my spindle speed from 3800rpm to 8500rpm using a belt and pulleys, just need time to get it done and doesnt seem to be much of that for me at the moment
Hood