Multiple robots per cell and safety

    I have multiple robot cells which have more than 1 robot per cell and each robot has its own controller cabinet. The entry gates are wired to the Fence Open safety signals, but recently our safety department has requested additional measures. The scenario they want to prevent is this... If one were to switch the controller out of auto, enable a teach pendant, and enter the cell, they want to make sure no other robot can be jogged while the original person is in the cell. I'm considering running the controller Auto/T1 switches through safety relays so that I can control the SERVO ON signal. Does anyone have a better idea? Robots are all R30i-B, communicating through ethernet to an AB L6X or L7X that is not a safety PLC.

    Thanks

    I do have DCS on all of these robots. Unfortunately, when we bought the cells they aren't even using DCS so it has only been a pain in the butt when mastering out a new servo/reducer. So if I get my learn on, and figure out DCS, am I correct in that I can use a UOP signal (say TP enabled) as an DCS input to another robot which will then prevent it from moving?

    While that would work, it wouldn't be safety rated.

    Ideally, what you would want to is buy a safety processor, setup SafeIO with it, then interlock the two robots together. Typically multiple robots in T1 are allowed, as long as all deadmans are pulled in. If not, I typically drop the Non-teaching safety input to the robots.

    Now with the pie in the sky idea out of the way, what you could do today, is wire up the two safety outputs you get (assuming these are R30iB+ controllers, and not mate controllers) to the other robot's safety inputs, and vice versa. Then you could setup the robot to stop itself if it is in T1, and sees the other robot in T1. If you want to get fancy and do the interlocked deadman idea, you could use one signal to monitor the mode state of the robot (in T1 or not), and the other signal to monitor the deadman state (pulled in or not.) You could then trigger the NTED on one robot if the other robot is in T1 and it's deadman is not pulled in.

    Check out the Fanuc position converter I wrote here! Now open source!

    Check out my example Fanuc Ethernet/IP Explicit Messaging program here!

    I agree with Nation, it would be ideal using a safety partner for your PLC, then communicating via CIP Safety through all the robots and creating the safe interlock logic on the controller side.

    Another option would be using an additional safety IO board on each of the robots. Then you can map the safe signals to the safe IOs of the boards and wire it between the robots.

Advertising from our partners