The servo drive is a Yaskawa SGD08AP and it is referred to as being a positioning drive (as opposed to torque/speed drives that are controlled by analog voltage). It can be controlled by three different forms of logic one of which is Step & Direction. Whereas the typical stepper drive system is open loop the servo drive system is closed loop. There are closed loop stepper drive systems but they close the loop in the drive. When a precision point error occurs (encoder feedback trails pulses output) then the stepper drive shuts down and displays an alarm. The typical servo drive systems rely on a DSP board to monitor the encoder feedback and raise an error when the encoder feedback is trailing the output signals by a predetermined number.
I know that the Arduino is capable of controlling a stepper drive. What I want to know is whether or not the Arduino is capable of reading and processing the encoder input. If that is insufficient input then advise me of such and I'll move on.
Ron