Re: Phase drive stepper mode

[Jon Elson <jmelson-at-artsci.wustl.edu>]

Lawrence Glaister wrote:

> I have been experimenting with the phase drive code in the emcmot module. Is
> anyone using this on a machine? I have it hooked up to an output monitor
> (cable with a bunch of led's hanging off the parallel port) and the results
> are a little different than I would expect. During movement, both phase
> lines do toggle, but they always stop with both outputs off. The duty cycle
> while moving does not appear to be 50% (expected for quadrature phase info).
> I expect to see a signal just like the output of a quadrature encoder, so
> depending on the position, I would expect to see both lines on or both lines
> off or 1 or the other on.... Ie, both off only occurs in 1/4 of the
> positions. I realize this is very new code and I am keen to test it/work on
> it as required to get it going. I would like to hear from other users of
> quadrature drive electronics.
> I am using a TMG 3 axis drive system on a mill.

You should be able to make the control jog .0001" at a time with the
incremental jog function (in manual, hit the letter i key, then use the jog
buttons.
Every push of the jog buttons will move the position the amount indicated
in the jog mode window.  Hit the i key until the jog increment is .0001" and
then watch the lights.  Now, if the output scale is set so that .0001"
of motion equals 4 motor steps, you would always see the motor stopping
on the same phase.  You could probably enter MDI commands to make
finer moves than the GUI allows in manual mode (ie. G01 X1.234567)
to subdivide the moves fine enough to see individual phases.

Jon