Thanks for the reply Hood,
Attached is my XML file.
I tried disabling the Y axis and this is what happens:
config ports pins - motor output
click check mark to disable
click apply
click ok
the reset button on screen flashes for a reset and the Y axis moves .002"
if I then re-enable the axis, apply, ok
the reset button on the screen flashes (just like the first time) but this time the axis does not move,
I jog the axis back to the same start point and do the same thing, disable, apply, ok
and the reset button flashes and the y axis has moved .002"
So leaving the Motor Output settings page causes the same type of motor movement problem as the Ref Y button.
So I think you may be right with the noise idea, I think the stepper motor is happier at certain positions and that if it is in between a little noise makes it jump to the next pole.
Now my question is why does Mach do anything at all if I click Ref Y if I do not have homing enabled on that axis?
Do you know what logic is followed when you ref an axis? If so maybe that would help me to determine where the noise is being interjected.
I really do not want to go thru all the wiring to figure this out since I am using all the original Bridgeport wiring from my BOB to the machine.
Additionally I noticed that if I am on the Diagnostics page and click ref X or ref Z they do not cause the Y axis to move, it is only if I click ref Y or ref all that the Y axis will move. So that has me a little confused as to where the noise is coming from, I would have thought the noise would be coming from the Z axis motor moving, (since it is the only thing moving when I do a ref all) but that is not the case. So what the heck does Mach do when you click REF Y if homing is not enabled on that axis that would cause noise in the circuit???
Is there some other way to "zero" the machine coordinates without using the ref button?
Since I do not use Homing on the x and Y I do not need to ref x and y but i would like to be able to zero them.
Because the Bridgeport has very accurate mechanical counters on the X and Y axis, what I like to do is jog the x and y to some position on the counters and then zero the machine coordinates. this way I can check during tool changes if the steppers have lost any steps.
Thanks again for the help,
John