Axis Jitter with Spindle On

Hi everyone!
This seemed like the correct place for this post. I apologize if it is not.
I am a bit new to LinuxCNC, but I have some experience with machining in general, programming, and computers/circuits.
Here is my setup: MicroProto MicroMill 2000 with stepper motors and original driver. Previously, Windows XP with Mach 3 was used to run this machine with no problems. I am trying to run the machine with the latest Linux CNC on a Dell Optiplex 780. I am able to move all 3 axes with no problem using the jog feature of LinuxCNC. If I execute a program without the spindle running, everything works fine. However, as soon as I turn on my spindle motor, with the "machine power" on (amplifier enable high, I assume) all 3 axes start to jitter in whatever direction they were previously moving. I can still jog under these conditions. The spindle motor is completely isolated from the stepper driver. It's on its very own outlet, its own controller/RPM readout, and its own power switch. The only signals configured to go over the parallel port are Amp Enable, and Step/Direction for each of my 3 axes. Everything else is set to "Not used".

Does anyone have any idea what is going on? Any help is greatly appreciated!

Thanks,
Mativi

Sounds like electrical noise from your spindle is getting into the step signals at some point

Sometimes a line filter on the VFD can help as can making sure the step/direction signals
are wired away from spindle or AC power wiring.

PCW,

Thank you for your response. Would it be possible for noise to be present when running Linux but not when running Windows? The physical setup in each case is completely identical. To run Mach 3, I just plug in the hard drive with Win XP and Mach 3 on it and boot up. To run Linux, I plug in the hard drive with Ubuntu and LinuxCNC on it and boot up. The cable layout, routing, and power arrangements do not change from one setup to the other.

Do you have any other ideas regarding why this might be happening?

I also noticed that I was not able set the step pulse duration to exactly what was being used by Mach 3. Each time I tried to set the Step Pulse duration (in stepconf wizard) to 2000000ns (2us) it would revert to 0.1us. I do not have documentation for what the pulsing should look like other than a 2us Step Pulse duration.

I hope to replace the rather old MicroProto drivers with a Gecko G540 soon, but I haven't the funding yet.

Thanks,

Mativi

Theres a stepconf bug with the wheezy release of 2.6 that has been fixed in 2.6.1
I would update that first to get stepconf working

Hi PCW,
I updated to the latest version of LinuxCNC and Stepconf. I generated a new config using stepconf with the same parameters. I am still having the same problem. As soon as I turn on the spindle (a separate motor and speed controller) all three of my axes start to twitch. This only happens when I am connected to the LinuxCNC machine and the stepper drivers are "enabled" (via LinuxCNC). Turning on the spindle with the stepper drivers on but not enabled does not produce this problem. This makes me think it is a software problem, but I am baffled as to what it could be.

This problem was non-existent on Mach 3.

Once again, I am using the exact same hardware in the same physical configuration. The only different is which hard drive I boot from. The stepper driver is the MicroProto Systems MicroMill2000HD/LE. I can job the axes no problem using LinuxCNC. I can even run jobs. I just can't have the spindle motor on at the same time (so I can run jobs that are useless)

Thank you!

Mativi

A possible long shot is that the Mach parallel port driver sets the port into EPP mode
but the linuxcnc driver does not, and on some parallel port hardware EPP mode changes the
output pin drive strengths, so if your BOB is marginal with standard parallel port settings,
this might explain whats going on.

Information on the BOB and drive connections might help narrow this down

Update: This problem has been resolved. The driver (MicroProto Systems) was looking for an ActiveLow input signal. I was giving it an ActiveHigh input. I just set the step pins to be inverted in stepconf and this problem was solved.

Thanks everyone that helped!