Safety with light curtain


we are using UR5 as main controller (we dont have any plc).
the robot runs into a cell without reduced velocity!

At our robot cell we want to add 2 light curtains.
Depending on the sequence we want to:

deactivate curtain1 when engine 1 is active (no safety signal)
deactivate curtain2 when engine 1 is active (no safety signal)

is there any safety program where we can implement this?
Just know such safety programs from siemens.

If not, how can i implement this?

Best Regards

To my knowledge, there is no dedicated safety program running on the UR. The safety I/O either see 24v and are happy, or don’t and fault.

When we use area scanners to reduce/stop the robot, we always put a Key switch on the controller to bypass the scanner so you can freedrive/program easier while inside the zone. To accomplish this, we just put a switch with dedicated contacts and run 24v across the switch into the same ports on the IO. Just be sure you have dedicated contacts so you aren’t compromising the dual-channel signal.

As such, probably the only way to selectively bypass the safety programmatically would be to have whatever machine its tending provide some signal, or else you’ll have to use an output from the UR to bypass the device. Just be warned, I doubt this would really be considered safe at that point, but that’s up to your risk assessment.

In short, you can take an output from the UR into a relay. Pull off 2 sets of contacts and land them in the same channel as your safety device. Then any time you turn on that output in the UR, your light curtain would be bypassed because you are providing 24v into the terminal.

Again, should this output get stuck on, your safety is NOT satisfied, and it’s NOT a safety signal coming out of the UR. You can set the IO to be “low when not running” which would help ensure there’s no stuck IO, but I don’t think this is technically a safe signal either.

What is your end goal with deactivating the curtains? are the 2 areas like part loading?

You can use safety inputs to reduce robot speed while parts are loaded and resume speed when clear

I think you can use safety inputs to turn on robot safety exclusion zones, but i could be wrong there