dray,
Only one axis running, namely the Z for the testing. Later you can swap the axis by using the X and or Y drive in place of the Z.
The X & Y should not be run while doing the test because of the inadequate power supply you have. We are trying to isolate the problem from other influences. You don't do a loop back and forth / up and down, but should first see how the number of pulses / indication in one direction is as compared to the number of pulses in the opposite direction.
Pulses .....one pulse sent to the drive is equal to the resolution in terms of linear movement. So 1/25600=.000040" of "possible" linear movement. Each move per pulse can and will vary some from each other and it can take more than one pulse to change the rotor position, etc. The rotor of the motor requires 200x 8= 2000 pulses to turn it one revolution. So 1/2000 x 360 deg=0.18 degrees =10.8 min which
is the approx equivilant of .0094" of circumferential movement on a 3" disc. So if the scribe line / mark was .005" wide ( a razor blade cut) you
would see the rotor rotate by one mark.
RICH