i have also linked my Encoder Output from spindle servo to c axis and ENC module.
but i am doing the spindle orientation (for the ATC) on the servo drive, this is enabled
by a digital Input on the servo and reported back by a digital Output from the servo.

So using the encoder signal twice does actually work?

From the vague replies i get from CSL its not to be done at any cost But i guess maybe that would affect sales of ENC modules ??

I will be trying this, my encoder will also be sharing the ENC channel1 input between main spindle and 4th axis spindle, i won't be doing dual spindle stuff so its either one or the other. I'll do the switching with a 74LS257BN quad channel, dual input switch IC, could have used relays but thats messy i think.

Yes, you can parallel the signal. Works on my setup.

Yes I can confirm it does works very well, for threading at least.

I still can't get spindle orientation to work properly - it does stop at a location, it will creep back to a location if needed, trouble is that the location it chooses is not the same each time?

Yes the encoder is 1:1 with the spindle and threading does work very well.

Do you have an index signal in your spindle encoder?

Yes, it uses the index for threading sync as far as i know.

So threading works, but orienting the spindle doesn't?

Yep thats it.

No error messages, it will creep to a stop each time but that stop is different

Which way do you orient the spindle? By setting in the plugin or M20?

Only tried the plugin, didn't know about M20?