From your video, your belts look like they are under-tensioned. Is it possible your belts are loose enough to be slipping on the drive pulleys?

At this point, I’ll take what I can get. I appreciate the feedback. Any way I can rescind the “answer” token?

Edit: marked as unsolved

I figured out a way to get a perfect heartbeat…

M307 H3 A-1 C-1 D-1 ; Disable heater 3 to make it available for Watchdog timer
M42 P3 S0.50 F2 ; Switch I/O pin 8 (HEATER3) on expansion header at 50% PWM at 2 Hz

Works great; inspired by this posting: https://www.duet3d.com/forum/thread.php?id=1866#p17119

Gotta love this forum.

Glad I made that a question then!

I would love to see these images, but alas, dropbox says 404 "file not found". Can you post them again?

M201 X3000 Y3000 Z1000 E800 ; Accelerations (mm/s^2)
M203 X20000 Y20000 Z8000 E1500 ; Maximum speeds (mm/min)
M566 X370 Y370 Z1200 E1000 ; Maximum instant speed changes mm/minute

With a Delta printer, shouldn't the X, Y & Z values for the above be the same, since they are for the servos at the towers and not the cartesian coordinate system axes?

Maybe you are missing the S parameter in your M570 statement. Did you wait 10 minutes (default S parameter time) after the heater fault for the power to be killed?

From Version 1.20beta8/New Features:

• When a heater fault occurs, the print is now paused and all heaters are turned off except bed amnd chamber heaters. After a timeout period (currently fixed at 10 minutes), the print is cancelled, all remaining heaters are turned off, and the firmware attempts to turn the power off as if M81 had been received.

From Version 1.20beta10/New Features:

• Heater fault timeout to cancelling print is now configurable (M570 S parameter, in minutes)

Original intent was a heartbeat of 1 cycle per second to prove the processor was healthy, which worked great in 1.18.1. Now the M42 has to wait for a long move to complete, which can take up to 20 seconds at first layer speeds. I would rather not wait that long to cut power to a non-responsive Duet board.

What about a M400 parameter (S-1?) that forces "do it now" rather than "wait for current moves to finish"?

Or, back to my original request of a heartbeat on the PS_ON pin…

@dc42:

If I decide to add firmware support for a heartbeat on PS_ON, what frequency would you want, and what duty cycle?

Figures; if it isn't broken, update the firmware until it is. Now that I am at 1.20RC3, my M42 commands that worked in 1.18.1 without having to wait for macros to complete, are now not working as coded. Somewhere along the way, this feature must have been "fixed".

Is this the reason that my 1.18.1 M42 commands are now waiting for macros to complete before executing?

Version 1.18.2/Bug Fixes…
"M42 gcode commands were not synchronised with movement"

If so, is there some other command I can use that will execute during a macro instead of waiting for it to complete?