Do the motors run in the same, or opposite directions?

I'm guessing that if you're using a racks, then the motors will physically run in opposite directions.
In which case, how has that been achieved?
By the wiring having been swapped for one of the motors coils, or by changing the polarity of the direction wiring to the driver?

If it's been done by swapping the direction wiring polarity, then the step/dir timing will likely be out of sync, which will result in the driver moving two steps out of position when the direction is changed (but only when the direction is changed in one way, the opposite direction change will be correct).


The simplest test for loss of position, is to setup a DTI against the axis in question. Then run a simple g-code program that simply moves the axis back and forth a short distance 50 or a 100 times, and see if the axis returns to it's original starting point against the DTI.