Robot E-stop over Ethernet - Guardlogix


Thread Starter


I am working on getting the parts together for a new robot cell and there will be a GuardLogix PLC running everything. My question is how do I connect the robots dry contacts for the e-stop and fence? AB does not make an Ethernet guardlogix module with relay outputs, they have a devicenet one though. I would be using a 1791 or a Point I/O setup for the safety signals. Do I use the output of one of those to control a safety relay?

James Ingraham

The output from the Point I/O safety module has to go to a safety-rated relay. For example, you could use a Guardmaster SI safety relay, something like the 440R-S12R2. Another example would be (Dold) UG6970 safety relay. Note that robot safety has extensive requirements. You're almost certainly in category 4 / PLd territory, which at the very least means you're going to need dual input to the relay module with two normally open contacts for the robot's safety circuit. Because robot safety is so touchy, bear in mind that my advice is not an attempt to design a safe system for you. (Legal disclaimer, basically.)

Good luck,
James Ingraham
Sage Automation, Inc.