I have a project with a UR3e and two UR10es. I would like to tie all three e-stop systems together. Per section 3.3 of the support article “CONNECTING AN EMERGENCY STOP DEVICE VS. A SAFEGUARD PROTECTIVE DEVICE”, “If more than two UR robots or other machines need to be connected, a safety controller is needed for the multiple emergency stop signals.”
Would a controller like this work? It looks like I could have 3 input pairs that each monitor a robot’s System Emergency Stop output pair and split the OSSD output pair between the robots’ Emergency Stop monitoring inputs.
Also, I believe that I could wire up 3 safety relays in series, similar to these, but this will take up a decent amount of room. I would have each robot’s System Emergency Stop output pair wired to one of the controllers, +24v wired to the first relays input pair, then daisy-chain the second and thirds input/output pairs, finally splitting the last output pair to all 3 robots.
So, the UR’s safety inputs do NOT detect crosswire shorts as it is, so if you truly wanted that level of dual channel safety, then yeah you’ll need a safety controller or relays. Seems like the one you linked would work. Alternatively, if you have the robots already, you could try just wiring them together with no additional devices. You’d just have to set each robot up with 2 of the Configurable Inputs as “E-Stop” that way you aren’t sharing contacts. I’m not 100% sure, but I might wager the reason UR says this is because if you were using the dedicated E-Stop ports only, then yeah, one robot getting E-Stopped wouldn’t drop the other, because the 3rd robot’s e-stop would be keeping the signal high. And maybe the configurable inputs will behave the similarly, I’m not sure. But it might work like this: