Rpi Left on while the Duet-3 board is off ?



  • One for at @dc42

    The extended boot times of the Duet-3/SBC really p*** me off so much so I am really considering running them in standalone mode.

    So I had a thought I which might over come the boot time, and I would like confirmation (or not) on the thought.

    Would the Duet-3/SBC complain much if the SBC was left powered on (to reduce boot times) or does everything require to be in sync (i.e both on at the same time) as I can separate their power supplies and control them independently of each other no problem.



  • @CaLviNx leaving it left on should be fine.
    The pi will just continue looking for duet until its on.
    You could also just supply 5v power to pi and duet all the time and then switch the 24v on when required.
    I've got the boot time to ~20 seconds by using a cheap SSD (60Gb) connected to USB 3. This is on a pi 4.
    I can also check the boot time of a pi 3 using an external hard drive if required.



  • When I worked at Logic PD, we optimized a Linux boot process so it was up and running with LCD, and a camera in less than 1 second.

    If you're interested in going that way, there are several articles that show the steps to reduce Linux boot times out there.



  • @jay_s_uk

    My main issue is that I need to send a shutdown -h now from a real computer every time I want to shut down the printer. Keeping the PI powered on will also solve that.

    However, how would I switch on the 24v supply? I cant use the GPIO, since they are all used to talk to the Duet... Is there a pin-header on the duet that could be used for this (assuming we power the duet's 5v logic from the RPI side)?



  • Leaving the RPi always on is essentially what we are doing. Below is a link to a power toggle script which uses M80 to toggle an SSR connected to a 24v power supply. While we are currently still using this, it needs variable support to be really robust.. fingers crossed I get to expand on this soon.

    https://forum.duet3d.com/topic/18848/duet-3-rpi-power-toggle-script



  • @sylvaindc or you could use execonmcode to shutdown the pi, triggering using a macro.
    Or you can just turn the pi off. I have 3 different duet+SBC machines and always just turn them off.



  • @jay_s_uk running using the execonmcode plugin sounds a bit safer then just pulling the power on the PI ;). It would make sense for this to be a normal part of the DWC framework wouldnt it?

    @dc42, would it be possible to do a remote shutdown of the PI from a standard M-code in the future?

    Cheers



  • @jay_s_uk said in [Rpi Left on while the Duet-3 board is off ?]

    Or you can just turn the pi off. I have 3 different duet+SBC machines and always just turn them off.

    But turning the Rpi off is contrary to the whole point the initial post and is therefore going off topic.



  • @CaLviNx said in Rpi Left on while the Duet-3 board is off ?:

    But turning the Rpi off is contrary to the whole point the initial post and is therefore going off topic.

    Maybe he meant turn the RPi off and leave it off 🙂 . That's what I do. The boot up time isn't an issue if you disconnect the bloody thing 🙂



  • @deckingman said in Rpi Left on while the Duet-3 board is off ?:

    @CaLviNx said in Rpi Left on while the Duet-3 board is off ?:

    But turning the Rpi off is contrary to the whole point the initial post and is therefore going off topic.

    Maybe he meant turn the RPi off and leave it off 🙂 . That's what I do. The boot up time isn't an issue if you disconnect the bloody thing 🙂

    In light of the forum recently becoming littered with people having quite numerous issues with their Duet-3's when used on conjunction with an SBC, removal of the SBC and running all my Duet-3 boards in standalone is an viable option.

    I also expect or resident moderator to be along soon getting upset about me voicing the truth.....



  • I've only recently started using a Duet 3 with Rpi but I do find it odd that's there is no power down procedure.

    I was a marlin person before getting the Duet and always used Octoprint and shut down the pi to avoid damaging the SD card.

    Was it always the idea to just turn the power off when using the Duet 3 with a SBC?

    I hoping not to have the issue I've read about on here.



  • @CaLviNx The RPi is a solution - the trouble is, the problem that it will solve is yet to manifest itself. 🙂

    When Duet 3 was being talked about, lots of people were jumping up and down saying "we must have an SBC to do all the "peripheral stuff". But now that they've got the SBC, nobody knows what practical use they can make of it. We keep getting told about the exiting new features but it's been what 18 months or so? - and not an glimmer of anything remotely useful that needs an SBC as a pre-requisite.



  • @deckingman said in Rpi Left on while the Duet-3 board is off ?:

    @CaLviNx The RPi is a solution - the trouble is, the problem that it will solve is yet to manifest itself. 🙂

    When Duet 3 was being talked about, lots of people were jumping up and down saying "we must have an SBC to do all the "peripheral stuff". But now that they've got the SBC, nobody knows what practical use they can make of it. We keep getting told about the exiting new features but it's been what 18 months or so? - and not an glimmer of anything remotely useful that needs an SBC as a pre-requisite.

    You are 100% correct, but the harsh reality is that the powers that be are (to be brutally honest) playing to the crowd instead of using logic.

    I know my next paragraph is going to ruffle more than a few feathers but hey I always tread where angels fear.

    The Duet team needs to recognise (and acknowledge) there is a very real problem. And they should notify users that there is a very real provable problem and that in the interim that it would be advisable to run the Duet-3 in standalone mode until such time that it is proven that the problem is solved.

    And it would be advisable for them to actually listen to some of long term power users (such as your self) who have the correct analytical skills, and those who are willing to assist them in testing the Duet-3/SBC combination, AFTER they have any meaningful features that the everyday user can see and see that those features are of use.

    Until we see any meaningful (useful) features the Duet-3/SBC combination is nothing but a complete waste of time.

    And the party line "of in the future" is bull**** we are here and now not in the future.



  • @CaLviNx there's now an addon for MQTT that's only available to use with an SBC attached.
    Can't think of any more benefits at this point in time.

    On the other hand, the SBC addon is very beneficial to LPC port users as results in a much more robust network connection.


  • Moderator

    @CaLviNx said in Rpi Left on while the Duet-3 board is off ?:

    I also expect or resident moderator to be along soon getting upset about me voicing the truth.....

    😰

    For what it's worth I often recommend people stick to standalone mode unless there is something specific about the SBC they want. It's still under heavy development and doesn't currently offer a lot. But that will change.

    There was a rather lengthy thread a while ago started by Danal (bless his soul) about shutting down the pi before removing power. While that's probably the ideal, the Pi OS is very resilient to having power removed abruptly.

    https://forum.duet3d.com/topic/15767/can-o-worms-pi-shutdown-vs-power-off?_=1604949943895



  • @CaLviNx I would say the biggest problem is that people are being pushed steered into buying an RP1 needlessly. On the Duet 3D web site, the description for the Duet 3 main board states..........

    "The flexibility of configuration and advanced features are enabled by our innovative RepRapFirmware 3 running on the Duet 3 Mainboard and our customised DuetSoftwareFramework running on a single board computer."...............

    There is no mention that the mainboard can be used in stand alone mode. That's why I mistakingly bought an RPi at the outset. I was also told at the time, that the Panel Due wouldn't work with Duet 3 so an SBC + HDMI touch screen would be the only way to control the machine "locally".

    So for anyone not familiar with Duet products, it is somewhat implicit that an SBC is a necessity. Whereas the reality is that an SBC is by no means necessary but might be a useful accessory to add at some time in the future when somebody has thought of some practical use for it.


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