Hi kentCNC,
I'm only just learning too so regard what I say with caution.
I don't know whether M3 can count but it certainly does have 4 encoder inputs. Could you
mount an encoder on the end of your stepper or maybe on the far end of the ballscrew?
If you can the you have DRO's built in to M3 that can read and manipulate them.
Do you have reason to believe that you are losing steps? Loss of steps can be measured reasonably
easily with vernier calipers or a micrometer. That method wouldn't warn you however.
I have read quite a few posts where different people have tried to use M3 to correct for loss
of steps and I believe most if not all have failed, warning yes, correction no.
Any reasonable correction strategy requires a closed loop design which is the norm for servos
but in its infancy with steppers. The vast majority of steppers are used open loop. My machine is
open loop and yet I have never lost steps unless I was trying to do something crazy or otherwise
demand more than steppers can deliver.
My recommendation is solve the loss or potential loss of steps problem then any warning/correction
strategy becomes redundant.
Craig