[Darc]

I mostly ask if for example an Allen bradley motor can communicate with a Omron drive (example only)...........

[ynneb]

I dont know about your example, but I do know that there are a few types of servos and you need different cards to drive them.
Brush and brushless servos, AC servos, different types of encoders attached to them. All these variances can require certain types of drivers. Some drivers can drive more than one type of servo too.

[Al_The_Man]

I have found generally DC servo components are much easier to mix-and-match, principally because the components are easier to 'reverse engineer' in the absence of any data.
With proprietary sytems from people like Allen-Bradley it is harder as their stuff is intended to be sold with their own controls, in the case of DC brushless and AC servo's there is a wider variation of feedback devices for commutation etc, so the 'reverse engineering' is a bit more involved, but manufacturers of motors like Kolmorgen and ElectroCraft and amplifier makers like AMC and Copley Controls issue all the data on their products so it is easier to mix and match.
The bottom line is see if you can get the technical data before you aquire an item.
Al.

[Kookaburra]

Check to see if it a resolver feedback or an encoder feed back. If it is a simple encoder feedback, chances are you can mix and match. A lot of the bigger companies are going back to a resolver type feed back where you can program the resolution you want rather than being stuck with a fixed CPR on an encoder. This resolver type system usually requires a matching drive and motor combination as they talk with each other. I agree with AL, best to do some initial research before buying anything.