I solved it. It was a simple low voltage/current issue of Rpi. Now I am powering it via seperate PSU rather than with duet 3. It works flawlessly.

Connected it and it works fine. Thanks!

Got it. I probably misunderstood the whole flyback diode concept wrong :). I will go ahead and try it. Thanks. Still learning

The contactor is actually going to power the heatbed SSR. I added the contactor as a safety measure if SSR gets break and start heating the bed as it is own. Duet 3 is supposed to turn on/off contactor when its printing only.

Sorry for my noob question but I am no electronics/electrical engineer. I checked the specs and it should be fine on the paper. What concerns me if there will be a sudden current spike that flyback diodes cannot handle (I dont know if flyback diodes has max current limit?) when contactor turns on/off. I cannot measure it since it happens too fast. I dont know if anyone tried a similar thing before.

I solved it. It was a simple low voltage/current issue of Rpi. Now I am powering it via seperate PSU rather than with duet 3. It works flawlessly.

Hi everyone.

I would like to know if its possible to control 110VAC / 24VDC (Coil voltage) contactor via duet 3 fan outputs (OUT7 thru OUT9 with flyback diodes). Does it damage the board during on/off sequence?

I measured the coil power draw and its around 6-8W total (About 0.3 amps) when its active.

This is the contactor that I would like to turn on/off.
https://www.automationdirect.com/adc/shopping/catalog/motor_controls/iec_contactors_-z-starters-z-overloads/fuji_contactors-z-_overloads/9_to_25_amp/sc-e05g-24vdc

Wow I cant even connect a single 24AWG 6inch cable that is literally connected to nothing, not even a ground. RPi lost its power once it triggers M80. When there are no cable present it works just fine. How sensitive are those GPIO pins? I am using RPi3 on my prusa with a fairly long amount cable connected to GPIO and its working fine.

Also I found the real issue here. Somehow when M80 is triggered it interferes with the custom python script I am using to control the power on/off behaviour and initiating it. I simply see no way how it interfaces itself with it. So its not power related but a scripting problem. I am using this script with different GPIO port numbers. https://www.hackster.io/glowascii/raspberry-pi-shutdown-restart-button-d5fd07

Is it possibly a bug present with M80 command and GPIO pins are interfacing somehow?

The most weird thing is it only initiates the script when a cable longer than a inch that is connected no nothing to any unused GPIO pins.

Ok update. I discovered the problem but not the definitive reason or solution so far. I am using unused 2 gpio pins (one is unused ground and the other is GPIO26 and set to pull_up) that is going to be connected to momentary push button on RPi4 to control a power off script. When its connected it must be drawing too much power since its a fairly long cable. I disconnected that cable to see if there is a problem and viola it solved the issue. Cable itself is not connected anything so far and checked it with multimeter if there is a short but its seems fine. Any thoughts?

Sorry for the diagram. I am not good at it and draw a very simple one.
You can disregard the timer relay and push button. So basically SSR is working fine and can drive 110v coils on contactor easily. The problem is when I connect the SSR to PS_ON on duet 3 RPI4 shuts itself down when it engages M80. It boots normally until it engages M80 from config.g file. Its not showing on diagram but for testing purposes I also powered the duet 3 via a seperate 24v psu that is not even connected to contactor. The result was same. Rpi4 shuts down itself down after 1-3 seconds later when M80 is initiated and its red power led still on while SSR kept latched on after M80 and duet 3 keep powered normally without any problems even though Rpi lost its power.

To test it, I even disconnected the SSR from contactor connection alltogether, powered the duet 3 with seperate 24v psu that is not connected to contactor and get the power to ssr from another 5v seperate psu that is also not connected to contactor.

The thing is when I replace the ssr with a smaller one it works fine. But the smaller SSR wont be enough for my purposes here.

Hi all,

I am trying to solve the problem with my power on/off control circuit but so far nothing. I have this (https://www.amazon.com/gp/product/B07DSXWPC1/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1) SSR that I am trying to use to turn on/off PSU via M80 command. I set the SSR to Active High via jumpers and connected the PS_ON to IN1 and 5V_IN to COM connector (or vice versa, I dont know if matters) . I supplied the power to SSR via a seperate PSU that is not connected to anything else.

The problem is when RPi4 boots up, issues M80 command and latches the SSR, then after a 1-3 seconds later RPi shuts itself down but the SSR keeps latched on and duet3 still powered on with all LEDs are lit. I suspect SSR is drawing too much power from 5V_IN port. I tried other combinations like setting the SSR to Active Low or only plugging PS_ON and leave the COM empty but so far nothing.

Do you think this SSR is not usable with with Duet 3 PS_ON pin? Or can I solve the problem with a 5V 10A PSU to supply the seperate power to RPi4?