I also vote on this feature, an script that runs when temp fail occurs. With m81 by default would be ok?
Maybe some conditions to choose whether it is over maxtemp, or any heater fault. Also a command to temporarily disable it in case someone is doing some tweaks and does not have an extra 5Vstandby source.
Many thanks for the clarification, so no risk of ground loops using a common 2-pin phone chargers.
To join the V- terminals on the PSU socket instead of on the Duet looks better also
Hi everyone,
I got myself a duet recently, and already installed it in my printer with delighting results. My setup includes:
-24v standard meanwell psu
-12v step-down modune, common gnd for fans and water pump
-AC mains bed controlled by SSR
Then I use a contact relay to switch PSU and bed, which is on the normally open side. To turn it on I have to momentarily connect the Normally-open and Normally-Closed terminals of the relay and it keeps on when M80 is written in the config.g file. I can use M81 and/or reboot the printer but not M80 unless it is physically connected again.
To solve this I thought about adding an spare 5V phone charger as always on to the board, but it's still unclear to me if I will have any trouble with it causing ground loops. It has been tried and seems OK, anyone knows a good answer to this?
*I have measured voltage between booth gnd terminals and by the time it was checked that was not any significant magnitude
A solution that comes to my mind is using the Normally closed side of the relay for the 5V phone charger, that turns itself off when the other circuit is activated.