Bipolar Stepper + encoder, does Granite support?

[snoman70]

I am in the process of learning this whole servo control thing, and I have some servo motors on another machine, but I really don't have access to them for a bit. I want to order a drive, but I want to make sure I'll have something to play with on my stepper machines. I know the VSD-XE supports steppers, but I can't find confirmation that they support steppers WITH encoder feedback...essentially just turning the stepper motor into a PM DC servo motor.

If it will, I'll place my order for a drive as soon as I get confirmation.

Thanks!

[Xerxes]

The answer for controlling stepper as high pole count servo motor is yes (theoretically). However in practice this may give poor performance because:

* Steppers have high voltage constant and top speed you will get probably will be only 100 to 500 rpm
* Encoders and steppers have some linearity error which makes this setup stepper to have uneven torque sensitivity over rotation angle. Only if you're lucky you'll get very linear encoder & stepper when there's no this problem.

So in other words, its not currently recommended to use this control mode. However open loop stepper mode works ok.