One more reply to my replies and then I gotta wait for some help!!
I've made some progress although I still don't know what's up. I set the VFD to use it's onboard pot for Hz change, Mach4/PMDX 107 still in charge of Run/Stop. Still had the problem!! So it isn't the 0-10v going out that's the issue, it's the spindle being told to stop and start. Never thought of that.
So I set the VFD back to using the onboard run button, and presto, the spindle runs and runs and runs. So I suppose the VFD isn't causing this heartache!
I guess I can go back to using Mach4/PMDX 107 to change Hz and manually start the spindle with the onboard button, but that's less handy than having Mach4/PMDX 107 control run/stop and the onboard pot handling Hz. This way an Estop in Mach4 will NOT stop the spindle, right?
So, any suggestions on how to fix the PMDX-107 starting/stopping the spindle? I have not put the scope on the 107 start/stop lines but figure my test pretty much confirms the VFD is being TOLD to stop and start randomly. I know this is probably some noise issue, but I haven't a clue how to approach it.
Thanks,
Tom