@DIY-O-Sphere It's working! I went to take a picture of my jumper set-up and accidentally "nudged" the cable connecting the 5V pin and PS_ON pin. My PSU turned on... I can now turn it on and off my PSU with M80 and M81 commands. I will double check the connections next time. Thanks a lot for your help, will mark this as resolved.

@DIY-O-Sphere Re-checked my wiring but I still can't get the relay to activate.

This is the relay, the 5V_EXT connection and the PSON connection:

Is activating the relay using a GPIO pin an option? If so, how would I do that?

@DIY-O-Sphere I added M80 to the end of the config file and applied the new configuration by running it but it did not activate the relay.

@DIY-O-Sphere

From Machine-Specific General Tab:

Board: Duet 3 Mini 5+ (Mini5plus)
Firmware: RepRapFirmware for Duet 3 Mini 5+ 3.3RC2 (2021-05-11)
Duet WiFi Server Version: 1.26

@dc42 Thanks. I could not get the SSR module working and due to the likelihood of future failures I have installed the SSR25DA but this is also not working.

I have M81 C"!pson" in my config.g file. I tried initially with i04.out and now have the positive input of the SSR25DA connected to 5V_EXT of IO_4 and the negative input of the SSR connected to pson. I have tried sending these commands: M80 C"!pson", M80 C"pson", M81 C"!pson", M81 C"pson, but the relay is not turning on the 12V PSU. My Duet Mini 5+ is being powered via the Micro USB using a 5V 2.5A power supply.

Am I doing something wrong or is there something I can try to troubleshoot this issue?

@dc42 Thanks. Is it also recommended to use a snubber like so between the two live wire contacts? In the past, I had to replace the SSR every 9 months or so which I'm guessing were failing due to voltage spikes.

@dc42 Thanks again for your patience and help.

@dc42

Thanks for your help.

@dc42

This is the ciruit with the transistor I used previously with the transistor, diode and resistor that can be seen in the previous photo:

https://www.susa.net/wordpress/2012/06/raspberry-pi-relay-using-gpio/

Here are the labels of the board:

I guess I can directly connect 5V to DC+, PSON to DC- and 3.3V to CH1?

Then when I use M80 and M81, I expect it will turn the relay on and off.

@dc42 it's an G3MB-202P 1565E, 5VDC Input Relay. Here's a datasheet of the relay https://components101.com/sites/default/files/component_datasheet/G3MB-202P-Datasheet.pdf and can't find a schematic for the board itself but it is this one: http://wiki.sunfounder.cc/index.php?title=1_Channel_5V_Solid_State_Relay_Module