Stepper motor runaway at startup

[jpbarad7]

Tom,

After a little tweaking to customize it to my system, WatchDogStatusRequests works perfectly to disable all drives whenever Mach3 closes.

I also brought the 12V that is used to activate the SSR which switches on the drives, in series with a manual switch (which allows me to cut power to the drive circuit while keeping KFLOP powered), to one of KFLOP opto-inputs.

Now KFLOP knows when the drives are powered ON or OFF, and if power is cycled, it won't re-enable the drives unless/until Mach3 is loaded or KFLOP is rebooted/power cycled.

Although it is true that we still do not know exactly why the drives sometimes ranaway after powerup, with the changes we made to the hardware and software, it can/will never happen again.

Your suspicion that the drives were probably receiving electrical interference from somewhere ('noisy' contactor circuit perhaps?), causing them to think they had received input, is most likely the case. I'm not sure how to actually determine if this is the case, but again, finding the cause of something that is no longer a problem isn't very high on my list.

Thanks again for all your help!

Jim