7i77 encoder split to amp and servo

Well you can do alot of things, doesn't mean it's always a good idea. Somebody just posted about those CUI encoders that according to the datasheet don't even drive enough current to operate the receivers on a Mesa card according it it's manual.....maybe it'll work, probably not a good idea. When you start having problems you have to ask "what are the things I did that were not good idea?" If it just works, why bother asking?

I have no idea what kinda drives or encoders we're even talking about here, just making suggestions specific to the questions that were asked.

PCW,
Nice board. 
I lack some fundamental electrical knowledge. In general, on a line driver type differential encoder, if the receiver is only single ended (my drive), it was my understanding that one can still read in just the A and B channels. If so, do /A and /B need further termination or can they be left floating/unconnected? 
Or is it better to just get a single ended encoder if the receiver is single ended? 

Tommylight,
I have a split setup on a lathe spindle that works very well with rigid tapping / threading and css. I'm reading in differential on both ends one to encoder card on vfd and the other to 7i77 for velocity control, so not trying something odd like current setup.

Current problem is trying to get a 4th axis indexer working. The drive (AMC ab30a200) only reads in single ended encoder for velocity feedback. I'm not sure why a new analog drive would have limited encoder channels in addition there is no encoder out from the drive to linuxcnc.
I think most of the digital drives have the additional encoder output. Unless I'm missing something, I'm forced to split it if I want encoder feedback.
One option is I can use current mode in the drive and read in the encoder on 7i77 only. Unfortunately  I can't get good shaft lock in current mode.
Best option so far is hall velocity feedback in the drive and encoder to 7i77. Shaft lock is good but runs somewhat rough. Suspecting noise and bad encoder signals. This drive is not isolated. That was an extra option.



 

I ended up using the encoder y board from mesa which seems to be working fine with the addition of having swapped the servo drive to an isolated version.