Author Topic: Updated PMDX-411 firmware, now constant Motion Underrun errors in Mach4  (Read 1865 times)

devinw

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During my trying to troubleshoot my spindle sped PWM not working (which turned out to be user error in Mach4), I clicked the box in the PMDX plugin config to allow the PMDX-411 to update firmware. It reported that the new version was the exact same one as before, but I let it update anyway. The update went off without issue.

Now, whevenever I jog (key or arrow mode), it instantly hits a Motion Underrun error. I tried maxing the buffers out and it made no difference. I have been running this machine for over a year now and never saw this issue before so I don't think there's anything wrong with the PC. Literally the only thing I did was let this firmware update run. Any ideas?

mntlvr

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devinw
Many have this same problem but are not getting any response to our call for help.
So if you get help let them know others need help on this issue with 416 and 424 boards

devinw

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That is concerning. They are taking orders still and the website is up, but yeah I see zero support here. Email is no go either.

Anyone try to call their office phone yet?

devinw

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Well this is fucking crazy. I just found a fix that worked for me:

Go to device manager settings for your Pmdx COM port and click "advanced" . Then uncheck the box for "use FIFO buffers". The 2 sliders should all turn grey.

This just eliminated all underrun errors and I just ran a complex part and it worked fine.

Why did this fix my problem? How did it work for me for a year prior without ever changing anything other than updating the Pmdx firmware (to the same version)? I have no idea and I would LOVE to know why.