Duet3 SBC Power Warnings



  • With quite a few people now having and using Duet3 boards, I'm curious to know if anyone else is having any issues relating to the Pi (as the SBC) showing the under-voltage warning in the top right of the screen as shown in the image below? I have Duet3 baords running on two very differnt printers, both with Pi4s as the SBC and both display the undervoltage warning when powered trough the ribbon cable from the Duet3.

    One of them is on a machine I run at work that and was from the first batch of boards. It had random crashes and used to disconnect from the SBC with SPI errors and the occasional CAN error for the expansion boards. The Pi4 on that system has since been changed to be powered separately from an Anker USB-C adapter and hasn't skipped a beat since - no warning icons or disconnects. At the time, I put it down to the fact that it's a very experimental setup with an awful lot connected to the Duet. However...

    I've recently finished upgrading my old workhorse from an old v0.6 to a Duet3 to use as a development platform for the other setup. It's been running without issue for about 2 weeks now. But yesterday, I swapped a microswitch endstop for an optical one and it seems it's taken it over a limit such that the Pi4 on this system is now showing under-voltage warnings - the attached image is from this setup. There's nothing wrong with the endstop. Luckily, despite showing the warwning, it hasn't caused any further issue at the moment, but I'm not comfortable with it.

    So, does anyone else have these issues, or is it just me?
    You'll only know if you have a display attached to the Pi's HDMI (it won't show if you're connecting through VNC ond clearly not through the web interface) or you can check by SHHing into the Pi and typing this:

    vcgencmd get_throttled
    

    If you get throttled=0x50000as a response, then you're fine. If you get throttled=0x50005 then you're not. Try it a few times - mine sits flashing on and off, so I'm clearly right on the limit.

    IMG_20200328_152831_LI.jpg



  • @ChrisP said in Duet3 SBC Power Warnings:

    vcgencmd get_throttled

    I have a Pi4B with a Logitech C270 USB camera being powered by the "default" jumpers and ribbon cable. No throttling. (No display either, so I can't say if lightning bolt or not). It is actively printing as I'm checking.

    At various points in time, I've also had a 7" touchscreen powered from the Pi. I will put it back on when a long print finishes (about 8 hours from now), and check throttle and the lightning bolt.

    But, as a 'soft' data point for right now, no issues with Pi, touch, Camera.


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