Duet 3 & Pi Power Wiring
I'm planning the power wiring for a new printer using a Duet 3 and pi 3B. I plan to power the Pi and a display from the Duet. I would like to be able to start the printer with a momentary button and shutdown the printer after a print is completed and the hot end has cooled. My start up approach is to use a time delay relay to hold the SSR enabled until the Pi/Duet combination is able to enable PS_ON. I'm reasonably confident this will work. Apparently the Duet can be configured to disable PS_ON after a print (although I haven't figured out how yet). Can the Pi detect the change in state of PS_ON (or other states) through software and initiate a Linux shutdown?
This is the time delay relay I am using. https://www.amazon.com/gp/product/B07M9VWL6Y/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
All suggestions are welcome.
I accomplished the samething using a pimoroni board. Essentially it is the time delay and latch built into an inexpensive little add on board.
For your desired function you may want to consider using two OnOff shims, one to control the soft power to the Duet3 and the other to control the graceful shutdown of the pi.
I plan to power the Pi and a display from the Duet.
Be cautious with this. It looks like you're using a Pi3b which may be ok provided the draw from the display is also low, but there have been some issues with the Pi4 which draws more power. Using a separate supply for the pi+peripheral side may prove more reliable.