how not to turn off Duet?

r123

Was in the middle of a bed levelling series of operations when realised it wasn't going to work. (The bed was sufficiently skewed that the probe wasn't touching at one point.) Not knowing how to stop the process just hit the "emergency stop" which then realised hadn't entirely worked: the LED lighting (connected to duet) was still on. So then turned off the machine.

On restart no DWC. Turns out the SD had been corrupted and needed to be formatted. The board was fine (though wifi had to be restarted via terminal). Did I do anything wrong (the emergency stop mid process) or was I just unlucky? Any comments?

dc42

I think you were just unlucky. An SD card may become corrupted if you turn off the power while data is being written to it.

zapta

@dc42, It seems from the description that the printer was idle when the power was turned off (per the prior emergency stop). Is it possible that the emergency stop corrupted the SD card?

(I use the emergency stop very often, sometimes even during pre-print bed leveling, since the Pause doesn't work).

dc42

@zapta said in how not to turn off Duet?:

@dc42, It seems from the description that the printer was idle when the power was turned off (per the prior emergency stop). Is it possible that the emergency stop corrupted the SD card?

Yes I think it is if the bed probing had just finished and the height map file was being written, because there are two tasks that can initiate an emergency stop, and those same two tasks can write to the SD card. I will log this as a probable bug.

zapta

@dc42, thanks.

r123

There are hardware solutions for keeping microcontrollers going just long enough to finish critical tasks (a capacitor, or something) at powerdown.

My takeaway from this:

going to maintain a duplicate carbon copy SD card
going to get a slightly less no-name micro sd adapter (discovered today that mine somehow produces interference that prevents laptop connecting to wifi, which created an hour of panicked debugging because needed internet for instructions!)

engikeneer

@r123 it's for this reason I use a separate 5v supply for the Duet and make use of the PS_ON capability. I can hit the estop (physical button or in DWC) and it will kill the 24V to motors, heaters etc, but the Duet still has 5v to run on. Also means you can get some idea what it was doing if you did have to hit the Estop. 10/10 would recommend

r123

@engikeneer that's definitely very interesting.

Someone just drew to my attention there's a neat way of backing up Duet with a script using the Reprap File Management utility. A secret too well kept.

https://railcore.org/software/backup.html

Never figured out why there isn't a one-click-download-a-backup button in DWC.

droftarts

@r123 said in how not to turn off Duet?:

Never figured out why there isn't a one-click-download-a-backup button in DWC.

That’s a good idea! @chrishamm ?

Ian

chiefmonkey

@engikeneer using the PS_ON configuration sounds like a more "typical" e-stop style setup. Quick question, how are you supplying the separate 5V for the board?

The only documentation I can find on this is supplying 5V to the board thru the SBC, is this how you are running or are you using some other means of input?

engikeneer

@chiefmonkey no I have my own small 5v PSU for my Duet WiFi (no SBC). You feed it in to the pin next to the PS_ON pin

chiefmonkey

@engikeneer Thanks for that, I'm running the 6HC so trying to figure out how to setup the jumpers to run 5V External while also feeding the SBC.