Originally Posted by
skrubol
There are 2 different basic ways to communicate with a servo, step/dir (control isn't in the loop, behaves just like stepper,) and encoder/pwm (servo drive tells the control where it is and the control tells the servo drive how fast to go or how much torque to generate.)
Servos still won't 'miss steps', even in step/dir mode. They may fall behind a bit where more torque than they can generate is needed, but they will either catch up when the load lightens or fault and stop completely. You will definitely want the fault line properly wired back to your control.
I'm not sure what it takes to mix step/dir and closed loop in LinuxCNC. I'd guess it's possible, but maybe difficult? (I'm still in the research phase on my LinuxCNC projet as well.)