E-Stop controlling auxiliary power

So we have several UR5e systems which are set up to use auxiliary 24V power sources instead of the internal 24V source – the jumper from PWR to 24V has been removed and replaced with the input from the larger 24V power source.
However, that power source and everything it powers are not currently tied into an e-stop. I can set up a separate e-stop to disconnect it, and even tie that into the UR control so that the new e-stop will also shut down the robot.
However, that leaves 2 e-stops: 1 controlling everything and 1(on the pendant) controlling just the robot.

I’ve been trying to figure out a way to use the pendant e-stop to shut down the line feeding the auxiliary power supply.
I’ve actually done that on another system which is using the internal power supply to feed all the I/O. That’s a simple matter of connecting a relay to a digital or configurable output - these drop power on e-stop.
If I try that with the current configuration, I wouldn’t be able to start/restart the power supply.
Is there another way to sense the e-stop’s status without needing the I/O panel powered?
I was hoping the PWR connection would go dead when e-stop is activated, but it still has 24V.

The UR5e manual seems a little bit confusing about whether you can do that or not. It says that you cannot use the e-stop for “sharing purposes” but it also shows an example on how to share the stop functions.


Full manual here.

Can you just stick a relay on the OUTPUT of your 24V power supply? So instead of killing power to the supply itself, you just kill power to anything its feeding? Then you can just branch off before this relay to any devices you still want on (such as your robot) and anything after the relay will be dead. And then you can switch the relay with normal controller I/O

I’ll play around with that when I get a free machine.
However, since I’m using an external 24V source to feed the I/O panel, and that 24V source is what I’m trying to shut down with the E-stop, I think I get into a circular logic issue.
Might be able to shut it down, but not be able to restart it unless I set up some sort of external start switch or something along those lines. That adds another switch & enclosure, plus another step for the operator at startup, so it’s probably no better than just adding a second e-stop (which I’ve done on 1 system already)

That’s another option., but ideally I’d kill the entire circuit for safety and convenience reasons.
On our more recent builds we’ve paid more attention to keeping other power circuits and bulky items in separate enclosures and generally given more though to neatness and component accessibility.
Unfortunately we have a couple of these systems which have everything crammed into the control box, which is tucked back under a desk.
It makes getting at connections and adding components a major pain.
We do have a young, eager junior engineer I can stick with the dirty work though :wink: