Thank you!.

I'll update the wiki so it is easier to find.

Now, it is not recommended powering the raspberry 4 via the duet, and instead use the raspberry official power adapter, via the USB-C plug.

When the duet 3 was being designed There was only the raspberry 3, so most probably if you use a raspberry 3 you will be fine if you power it via the duet.

That being said, it is not recommended because it is not worth the hassle for the duet community to support all the gremlins that came with this setup (and potential dangers, as you are bypassing some raspi's protections), but that doesn't mean it can't be done, or that it won't work.

I haven't tried this yet, as I'm still commissioning the printer in which I intend to use a duet3, but what people with this setup is doing is:

• Disable the internal 5v regulator (remove the Int_5V_EN jumper)

• Use a 5v industrial power supply (with an output adjustment potentiometer), with enough power, and thick enough wires, and connect it to the EXT 5V header

• Power the raspberry via the ribbon cable (leave the 5V -> SBC jumper ON, and the SBC -> 5v open)

• Adjust your power supply output voltage so its exactly 5.5v with your raspberry idling.

• Measure what voltage is receiving your pi. It should be in the neighborhood of 5.25v, and definitely more than 5.0v.

If you cannot reach this voltage, DO NOT increase your power supply past 5.5v or you could damage your duet.

This usually means you have too much draw in your raspberry (too many peripherals) or too thin wires.

In that case, you could try a powered USB hub, if the peripherals are the problem, or using the official raspberry pi USB-C power adapter.

If you want a more integrated solution, and you 5v power supply have adequate ratings for powering the duet and the raspy, you could run a second set of wires for the raspberry, and power the raspberry via one of the free gpio pins (you will have to mess with the flat ribbon connector, as it covers all the gpio pins) or via the POE header (the 4 pin header next to the Ethernet jack) you will only use 2 of the 4 pins, search for the pinouts.

Lastly, most of the information is taken from this thread: https://forum.duet3d.com/post/179406

I did it!

You just have to send a M911 with an absurd voltage way over your current vin, and the auto-pause will trigger right away.

So instead of having the M911 in confg.g, you put the full command in your trigger file and you are all set.

Just remember y your duet doesn't power cycle, you will need to send an m911 with more beliable values, but if your duet really did lose power, when you power up the duet again it will have the power-pause disabled.

I also in the process to "update" my duet 2. I have ordered a few pcbs and currently I'm waiting for the components, so as soon as I test them I could sell the spares.

I'm from Europe (spain) BTW

I did it!

You just have to send a M911 with an absurd voltage way over your current vin, and the auto-pause will trigger right away.

So instead of having the M911 in confg.g, you put the full command in your trigger file and you are all set.

Just remember y your duet doesn't power cycle, you will need to send an m911 with more beliable values, but if your duet really did lose power, when you power up the duet again it will have the power-pause disabled.

Just think of the mosfet (the device controlling the pin) as a switch between the pin and GND.

When you issue an M80, the switch closed, so there is a path to GND.

When you issue an M81, the switch opens, so there is not path to any of the power levels.

As far as i know, you can't change this behaviour (use m81 to "close" the pin) so if you need to control a device that is active high you will need external circuitry like a 7404).

What you can do, is changing the default state. If you want your duet to power on as soon as it is supplied power, just add M80 to your con fig.g

If you want your duet to start powered down (i mean the ps_on signal) you don't have to do anything, but you should add M81 in your con fig.g, so the power control appears in your duet web control interface (in RRF3 the ATC power control block won't appear until you have issued a m80 or m81 command)

and lastly @oliof YES if you feed 5v via the ext 5v header you have to remove the int_5v jumper.

For those using the PS_ON signal, remember that it is an open drain output switched by a AO3400A. That means:

• When it is active (M80) this signal is pulled low (so it is like a short to GND)

• When it is inactive (M81) this signal is floating, so you need to add a pull-up if you want a proper high level voltage.

• The AO3400A maximum ratings are 30V 5.7A (but the current rating depnds on many factors, divide it by half to make sure)

• If you are controlling inductive loads like relays by themselves (withouth a module), add a flyback diode

As far as I concerned, duet monitor its input voltage, and if it fails blow a defined threshold (with the M911 gcode) it will save the current print position, and execute a gcode trying to save the print.

Is there any way to trigger this functionality via an external pin, just like prusa does? Yes, i know that prusa boards shut the heater via hardware when this signal is triggered, but even without that functionality, an external power detection board should be much quicker to detect the power loss than the duet.

But here is the problem. I know i can trigger macros with inputs, but what gcode should I use? The normal pause wouldn't do since it will execute all the commands in the buffer, and then the sys/pause.g and most probably power will be lost long before those movements complete (probably even before the command buffer is flushed).

Ideas?

Now, it is not recommended powering the raspberry 4 via the duet, and instead use the raspberry official power adapter, via the USB-C plug.

When the duet 3 was being designed There was only the raspberry 3, so most probably if you use a raspberry 3 you will be fine if you power it via the duet.

That being said, it is not recommended because it is not worth the hassle for the duet community to support all the gremlins that came with this setup (and potential dangers, as you are bypassing some raspi's protections), but that doesn't mean it can't be done, or that it won't work.

I haven't tried this yet, as I'm still commissioning the printer in which I intend to use a duet3, but what people with this setup is doing is:

• Disable the internal 5v regulator (remove the Int_5V_EN jumper)

• Use a 5v industrial power supply (with an output adjustment potentiometer), with enough power, and thick enough wires, and connect it to the EXT 5V header

• Power the raspberry via the ribbon cable (leave the 5V -> SBC jumper ON, and the SBC -> 5v open)

• Adjust your power supply output voltage so its exactly 5.5v with your raspberry idling.

• Measure what voltage is receiving your pi. It should be in the neighborhood of 5.25v, and definitely more than 5.0v.

If you cannot reach this voltage, DO NOT increase your power supply past 5.5v or you could damage your duet.

This usually means you have too much draw in your raspberry (too many peripherals) or too thin wires.

In that case, you could try a powered USB hub, if the peripherals are the problem, or using the official raspberry pi USB-C power adapter.

If you want a more integrated solution, and you 5v power supply have adequate ratings for powering the duet and the raspy, you could run a second set of wires for the raspberry, and power the raspberry via one of the free gpio pins (you will have to mess with the flat ribbon connector, as it covers all the gpio pins) or via the POE header (the 4 pin header next to the Ethernet jack) you will only use 2 of the 4 pins, search for the pinouts.

Lastly, most of the information is taken from this thread: https://forum.duet3d.com/post/179406

Thank you!.

I'll update the wiki so it is easier to find.

The fire safety guide, in the hard shutdown of heaters section (https://duet3d.dozuki.com/Wiki/FireSafety#Section_Hard_shutdown_of_heaters) mentions that the firmware, in case of a heater fault, can use the PS_ON signal to turn off the heaters (providing there are external componentes, such as a relay, using that signal.).

Is this implemented by the firmware? As i haven't seen it in action in my printer in response to a heater fault. That being said, i haven't experienced an uncontrollable heater fault, only badly calibrated heaters that trigger the preotection and are shut down, so the temerature start to fall inmediayelly.

So if its implemented, under what circunstances is this funcionality triggered?