Controlling a 30amp 12v Power Supply

I don't know if anyone will find this useful but its something I have done recently as I wanted my RAMPS to be able to turn off a 12v 30amp power supply when printing was finished. I haven't seen anything about how to do this about so I thought I would document my way.

Below is a basic diagram of my solution. Its basically a solid state relay attached to the ps_on pin on the ramps but with a momentary push button across its terminals to bypass the solid state relay. Pressing this starts the power supply which then fires up the ramps. A fraction of a second later the RAMPS turns on the solid state relay which takes over supplying the power supply. The power supply remains on and under the control of the RAMPS and the whole system can be shut down with the M81 command.



Feel free to ignore the ramblings of a mad man.

Edited 2 time(s). Last edit at 05/14/2013 06:20PM by lazzymonk.

I bet if you looked inside, you could find a wire that can turn it on and off, or a contact point thats probably labeled. anyways my psu doesnt even have the fan running unless its using the bed and even then only occasionally.

Just be sure a resistor is in series to the scr. you don't want a 100ns current spike from capacitance to damage the arduino pin!

I've got a similar setup (no push button as my PC powers Arduino using US with a subtle change so PS_PIN is 0 by default. Using M80/M81 I power on or off my power supply. I do use a solid state relay too, just directly connected to the Arduino pin as [mine] it is opto-isolated. No problems so far and peace of mind that power supply will be switch off at the end of the print.