Mesa 5i25 skipping commands

Hi all,

I'm pretty new to linuxcnc and am hoping someone can point me in the right direction.

I have linuxcnc set up with a 5i25 card going to a G540 unit then going to my taig mill.

I've made a few parts with it, but today I made my first part that requires a few hours machining time. After about 20 minutes(it varies), the stepper motors stop working for a second or so. It looks like one command is skipped. When they start working again, the coordinates are off and the part gets ruined. A couple times I saw it happen. The servos just stopped, they didn't struggle or anything so it doesn't seem like anything is binding up. I did take the servos off to check everything out and they looked okay.

Any ideas on where to start looking for the problem?

The last three times I tried it, I moved the tool to part 0 on all three axes and the x axis was the only one that was wrong. I guess I could try swapping the x driver on the G540 with the unused driver and see if that fixes the problem. There must be a way to do that.

I was also thinking about buying a cheap parallel port card to see if the 5i25 is the problem.

What are you step timings?

The Gecko specified timings will not work with the 3.3V signals the 5I25 outputs
AFAICR you need at least 2.5 usec (2500 ns) for step time

Would I find the step time setting in the 5i25 firmware somehow, or is it a linuxcnc setting?

its set in the hal or possibly ini file

I found a parameter called steplen in the hal file that is set to 1000 on each of the three axes. I'll try setting that to 2500 to see if that helps.

eweb101 wrote:

I found a parameter called steplen in the hal file that is set to 1000 on each of the three axes. I'll try setting that to 2500 to see if that helps.

And that worked! Thanks for the help.