Universal Robots Forum

Safeguard Stop based on machine stopping

I am running a UR5e with a machine tending application. I would like to set it up so that, when an error occurs on the tended machine and it is stopped, the robot also stops.
The machine has a tower light (user manual of light found here: https://info.bannerengineering.com/cs/groups/public/documents/literature/142406.pdf)
When the machine encounters an error, it activates the red light on the tower, puts a message on the screen, and stops the machine.
I want the robot to also stop when the machine has an error to prevent damage to either, but I’m struggling a lot with the wiring. I’m an absolute novice with circuitry. I’ve been trying to put wires in both the Safeguard Stop DI and DO spots on the robot side, which I’m trying to put in parallel with the wires that go to the red light and the positive side, respectively. From my incredibly limited knowledge, I think that will complete the circuit and allow both machines to keep running, but I cannot get it to work.
I’ve tried every combination I can think of, but no matter what the robot just puts itself into safeguard stop if there are wires connected at all, no matter the status of the lights. I also had the robot trigger a safeguard stop when the wires were plugged in on the robot side but completely unattached on the other side. I do not understand what is happening.
Am I approaching this problem in the right way? Is there a better way to accomplish this? Would a red-light sensor work? Do those even exist?
Any help is much appreciated!

Please correct me if I am wrong, but it sounds like you are creating a Normally open switch on the safeguard stop connections when they need to be normally closed to function properly. Meaning they are closed when running and they open when it needs to stop.

Does your application require it to be safeguard or Estop?
You could connect to a Digital Input and set that input action to “Stop-Program” so that when the light is enabled it will set the input high and stop the program. This can be found by going to Installation Tab → General → IO Setup and selecting the Digital input you are using. Though you should also note that this signal should be low normally and go high when it should stop.


If you mean that even thought you change your safeguard stop back, the robot still cannot go back to the normal mode.

Here would be the possible issue.

In the default setting of polyscope, when you trigger the safeguard stop, you also need to connect another pair of signal as the “safeguard reset” and then activate the reset signal to make the robot go back to normal mode.

If you just want the robot go back directly without any rest signal to confirm, you just go to the I/O page like below to set the “safeguard rest” to Unassigned.

I think that you are right about the normally open switch. I’m trying to avoid using an Estop. When I switched to a Digital Input it worked, so thank you!

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