Re: Loosing steps on a hybrid stepper/servo system
The Aliexpress link doesn't work except for you... e.g. it wants a login. Can you describe the unit you purchased? Find a sales link for it?
I ask because I'm trying to understand what is the controller for the servo. E.g. is it an all in one unit with motor, driver, encoder, and servo controller in one package? Or is it motor / encoder, and then a separate driver, encoder, and what is the controller in that case?
Because the error is apparently in the encoder signal, there are a few sources:
1. The encoder could be slipping or otherwise not putting out correct signals (unlikely)
2. The wires from the encoder could be picking up RF interference, cross talk (RF interference from each other) or just be weak. More likely if the wires are long, unshielded, or thin.
3. The controller could be losing counts. Usually there is an error indicator for this (there is on my BOB PID) but god knows what the stuff from China has in it. This is more likely if it happens more often when moving quickly or when the unit is shaking.
Once you have a likely cause, you can move on to how to resolve that issue.
James hosts the single best wiki page about steppers for CNC hobbyists on the net:
http://www.piclist.com/techref/io/steppers.htm Disagree? Tell him what's missing! ,o)