Inverting PS_ON levels
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I recently upgraded to a Meanwell 24V PSU and it's finally time to wire up the remote on/off feature of the Duet/PSU. Sadly the PSU operates at inverted logic levels compared to the Duet PS_ON terminal.
My idea was to take the PS_ON signal and hook it up to a RPi Zero W that I already have streaming a video. With the RPi I want to invert the signal and wire it to the PSU RC+. The RC- terminal would be wired to ground.Is this a valid way to do this?
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Keep in mind that the GPIO pins are 3.3v, however, it does sound a little complex just for inverting a signal.
I have a Meanwell supply with an optocoupler and a couple of resistors to invert PS_ON.
If you're handy with a soldering iron it's another possible solution.
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I've recently wired up one of those PSUs with an inline logic inverter, which I had from a radio control plane, connected to the PS_ON. I reckon your plan should work. The rpi will need to connect the RC+ on the PSU to ground/RC- to turn off the PSU. RC+ can float open circuit or be connected to the +5v standby to enable the PSU. The PSU labelling is confusing, but think of RC+ as the signal wire to switch, RC- as ground, and +5v as +5v. The only problem I can think of is that the standby 5v only supplies 500mA - that might not be enough to power the duet and rpi....
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@insertnamehere said in Inverting PS_ON levels:
I have a Meanwell supply with an optocoupler and a couple of resistors to invert PS_ON.
If you're handy with a soldering iron it's another possible solution.Soldering is not an issue, how did you make a resistor based inverter?
@pawprinter said in Inverting PS_ON levels:
I've recently wired up one of those PSUs with an inline logic inverter, which I had from a radio control plane, connected to the PS_ON. I reckon your plan should work. The rpi will need to connect the RC+ on the PSU to ground/RC- to turn off the PSU. RC+ can float open circuit or be connected to the +5v standby to enable the PSU. The PSU labelling is confusing, but think of RC+ as the signal wire to switch, RC- as ground, and +5v as +5v. The only problem I can think of is that the standby 5v only supplies 500mA - that might not be enough to power the duet and rpi....
I have a separate 5V PSU wired, so that will be a non issue.
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@nxt-1 +5V is from the Meanwell aux supply.
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@insertnamehere are the 5V @ 500mA (says 300mA in the datasheet) enough to power the Duet reliably?
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@devleon In the OPs case possibly not. I'm using a Meanwell HFG600 which is 5V @ 500mA in the spec.
I don't have a panelDue attached and fans all run off the 24V.
I've seen no problems using a 500mA supply over 100s of hours printing.
