How to wire PS-ON to control PC Power Supply?

Hi all - have searched internet and reprap.org for how to use Ramps 1.4 to control power supply and found several references to the fact that is it possible, but no clear guidance on how to connect. I have an ATX power supply with green & black wired together, so if I manually turn on PS it works great with my ramps 14. prusa. I want to be able to turn power off and/or on using G code/M code so I can do unattended builds, or overnight builds but I must be using the wrong search terms because I can't find any reference on how to wire up the control side of PS. ANy help???

You can connect the green wire to the PS_ON pin next to the reset button.
Most firmwares are already setup to control this pin with the following gcodes.
M80 for on
M81 for off

Thanks for the info! very useful.

Up until now I've just been sending the end code to turn off the heaters and motors but this is much nicer.

Does the ATX PSU provide enough standby power to keep the Arduino awake, or are you using a separate 5V supply? I currently power off the 12 volts, which obviously won't work if you turn off the 12V supply...

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Does the ATX PSU provide enough standby power to keep the Arduino awake

Yes, easily. IIRC, the ATX specification guarantees 500mA on this line, an ATmega needs between 10 and 100 mA. Pololus ask for 5mA per each, IIRC, in case you feed them from standby, too.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Traumflug Wrote:
-------------------------------------------------------
> Does the ATX PSU provide enough standby power to
> keep the Arduino awake
>
> Yes, easily. IIRC, the ATX specification
> guarantees 500mA on this line, an ATmega needs
> between 10 and 100 mA. Pololus ask for 5mA per
> each, IIRC, in case you feed them from standby,
> too.


Thanks Traumflug! Can I leave the Ramps diode D1 in in this configuration, or do I need to remove it?
Also: On the Ramps 1.4 board, next to the ps-on pin are two pins labled 5V and VCC. Can I attach the 5V standby supply to one of these?
Wish there was some Ramps documentation that actually described how these connectors were to be used...

Yes, you can supply 5V power there, but when using an ATX supply its easier to just leave D1 in place and let the mega run from the 12V supply. If you were using a higher voltage and needed to remove D1, and you wanted standalone operation, then it might make sense to provide a separate 5V supply.

Andrew Smith Wrote:
-------------------------------------------------------
> Yes, you can supply 5V power there, but when using
> an ATX supply its easier to just leave D1 in place
> and let the mega run from the 12V supply. If you
> were using a higher voltage and needed to remove
> D1, and you wanted standalone operation, then it
> might make sense to provide a separate 5V supply.


Thanks Andrew - but the point is to have the Arduino turn off the 12V supply and keep running from 5sb. Almost feel like I need a diode in the 5sb line to keep the 12V from feeding back down the line. Sequence: Turn on the ATV supply. 5sb comes up, no 12V. Arduino boots and waits for commands. Arduino turns on 12V when ready to print. Arduino turns off 12V when done. Arduino waits for more commands until the ATX power switch is thrown off. Will be sweet if I get it working...

Johnnyr (good man) got in touch with me and got me straightened out. He also updated the WIKI with more info, so rather than quote him I will just direct future callers there...

Edited 1 time(s). Last edit at 05/24/2012 03:24PM by rmm200.

i think you would just have to take the 5v from the psu to a 5v pin on the ramps board, i doubt there would be a issue with that, i would also think if you wanted to be on the safe side you could take out D1 if you wanna be extra safe.

ps thats my understanding, but i am far from a expert

Edited 1 time(s). Last edit at 05/24/2012 10:49PM by dissidence.

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[mike-mack.blogspot.com]

jonnyr,
In this image, [reprap.org], is the PS_ON thru hole to the right of the PS_ON text or the larger diameter hole above the PS_ON text

The input is the one between "RAMPS 1.4" and "PS" in PS-ON (nearest the edge of the board). This is where you need to connect to.

The larger diameter hole is part of the Reset switch.

Quote
rmm200

Johnnyr (good man) got in touch with me and got me straightened out. He also updated the WIKI with more info, so rather than quote him I will just direct future callers there...

Sorry to bring up old thread, but which WIKI got updated with this information? How did you end up wiring this up? Did you remove the diode?

Thanks,
CP

they say a picture is worth a 1000 words.. this is what i did works great

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swe3tdave
they say a picture is worth a 1000 words.. this is what i did works great
[attachment 30471 PS_ONSmall.jpg]

Thanks.

A follow up question, I have the ps-on wired up, but if I have usb disconnected the atx supply turns partially on. If I connect the sub then it turns it off fully. Do I need a resistor or something else on wire?
Thanks

if the 5v standby of your psu is not powerfull enough, it might start to heat up, if that is the case, its possible that the fan would turn on automatically.

Do you have the specs of your power supply on the 5v standby? How many amps?

You could use a separate 5v power supply... Or just keep the usb connected...

Quote
swe3tdave
if the 5v standby of your psu is not powerfull enough, it might start to heat up, if that is the case, its possible that the fan would turn on automatically.

Do you have the specs of your power supply on the 5v standby? How many amps?

You could use a separate 5v power supply... Or just keep the usb connected...

You misunderstood my question. I am not using the 5V standby to power arduino, but the USB. But am wanting to use the ATX power on feature to turn on the ATX power supply, which works as long as the arduino has power. But if I remove power to arduino by disconnecting USB, the ATX power supply tries to turn on. It looks like this PS_ON pin goes directly to the arduino, so is there anyway to fix this without having to keep arduino powered up all the time?

there are two diode on the ramps, the one located under the pololu, you need to remove it if its still there. If its not there, or you already removed it, i do not know what's going on, i suppose there might be a weird feedback somewhere...

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CptanPanic
You misunderstood my question. I am not using the 5V standby to power arduino, but the USB. But am wanting to use the ATX power on feature to turn on the ATX power supply, which works as long as the arduino has power. But if I remove power to arduino by disconnecting USB, the ATX power supply tries to turn on. It looks like this PS_ON pin goes directly to the arduino, so is there anyway to fix this without having to keep arduino powered up all the time?

My guess is that if the arduino loose power, the PS_ON pin (yes, it goes directly to the arduino) goes to ground..

Its like taking the PS_ON wire and touching the black wire.

That is why you need to put the 5Vstb on the RAMPS board so the pin does go to a LOW state.

A test you could try is by putting a multimeter on the PS_ON pin AND GND and then, disconnecting the usb cable.. you should see the meter going from 5V to 0V (and that would be normal as there is no more power on the arduino board).

Is this possible on a Melzi board (zonestar p802)? I cannot find the PS-ON connection location on the board

I am curious, on a PC there is a Monetary On/Off switch connected to the motherboard that signals the CPU to pull the green ATX wire to ground turning the ATX power supply on. On a RAMPS 1.4 where is the Monetary On/Off switch wired to?

I tried to figure out the power on the RAMPS 1.4 to the Mega2560 but the schematics I have must need a magic decoder ring to read. The RAMPS 1.4 has 7 connectors that plug into the Mega2560 yet the schematics show U1? On the Mega2560 none of the connectors are listed as Jn, I'm old school and don't have the latest decoder ring I guess. Simple things like the Power On pin (D12) goes to what pin on the Mega2560 elude me.

No Monetary switch

mega has be powered on always

ramps is directly connected to green ATX wire to the PS-ON, this is pulled low by the mega via gcode

M80 ATX_Power_On
M81 ATX Power Off

[reprap.org] look at the bottom left panel "Power". D12 is connected to PS-ON
D12 is the pin, as defined by ardunio
[www.arduino.cc] you find that D12 is really PB6 ( OC1B/PCINT6 )

Here is the decoder ring [marcusjenkins.com]

Edited 4 time(s). Last edit at 08/10/2016 05:19AM by Dust.

Quote
Dust
No Monetary switch

mega has be powered on always

ramps is directly connected to green ATX wire to the PS-ON, this is pulled low by the mega via gcode

M80 ATX_Power_On
M81 ATX Power Off

That is a shame, looking forward to adding an on/off switch

Quote

[reprap.org] look at the bottom left panel "Power". D12 is connected to PS-ON
D12 is the pin, as defined by ardunio
[www.arduino.cc] you find that D12 is really PB6 ( OC1B/PCINT6 )

Here is the decoder ring [marcusjenkins.com]

Thanks, that and the data sheet answer the questions.

Just a comment - I have an ATX supply and the on-box switch is a PITA as otherwise I could hide the psu on the shelf inside the unit I made to stand the printer on.
Currently the green wire is just linked to ground, I will break it and add a remote switch on the frame of the Prusa.