Hello all. I have a system that includes 4 machines (each with its own PLC) and then this Fanuc Robot that I am integrating, all connected via E-net IP. My question is, how do I use the same I/O mapping between these machines and the robot? When I set up the next PLC in RoboGuide, do I still use rack 1 for all 4 of them? Thank you
Multiple PLC's, one robot
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ceilingwalker -
August 5, 2023 at 5:09 PM -
Thread is Unresolved
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Why? You should only have 1 PLC be the master to the robot (for UI signals). And each PLC if connected would need to not overlap on any signals. But I think a better approach would be to choose 1 PLC to handle the robot communication and have the other PLCs work though that one master PLC.
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Why? You should only have 1 PLC be the master to the robot (for UI signals). And each PLC if connected would need to not overlap on any signals. But I think a better approach would be to choose 1 PLC to handle the robot communication and have the other PLCs work though that one master PLC.
The problem with that approach is, let's say the PLC I make the master is offline, that brings the entire system down. This is a very real scenario as sometimes the machines have issues but I can't have it prevent the others from running.
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Ok that makes sense.
I think you have 2 options. Add 1 small PLC to be the communication hub, or have the robot itself play that role.
What program start method do you use? UOP? If so you could create a BG Logic program with flags mapped to the UI and UO signals and that BG Logic would act like the master PLC.
Then for each PLC, it is all rack 89, but each connection would be a different slot #, 1-4.
I wouldn't do any UOP directly to the different PLCs in that case but instead block of 4 sections of DI/O. If you need to send the same UO signal to multiple PLCs you can use the flags mentioned before to turn on 4 separate DOs in BG Logic.
Basically flags and BG Logic take the place of your master PLC and each real PLC gets it's own set of Separate DI/O.
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Ok that makes sense.
I think you have 2 options. Add 1 small PLC to be the communication hub, or have the robot itself play that role.
What program start method do you use? UOP? If so you could create a BG Logic program with flags mapped to the UI and UO signals and that BG Logic would act like the master PLC.
Then for each PLC, it is all rack 89, but each connection would be a different slot #, 1-4.
I wouldn't do any UOP directly to the different PLCs in that case but instead block of 4 sections of DI/O. If you need to send the same UO signal to multiple PLCs you can use the flags mentioned before to turn on 4 separate DOs in BG Logic.
Basically flags and BG Logic take the place of your master PLC and each real PLC gets it's own set of Separate DI/O.
So, create DI/O that are PLC specific, use different slot numbers for PLC's? This will make the robot the master and all the PLC's slaves? I need to study the use of flags and BG Logic program since I am not savvy with them yet. Thank you.
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Technically the PLCs will still be EIP Scanners and the robot will be an EIP adapter. But the robot would control its own UOP.
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You will need there scanners setup on the robot. One will be the master that controls the UOP's.
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you could create a BG Logic program with flags mapped to the UI and UO signals and that BG Logic would act like the master PLC.
Then for each PLC, it is all rack 89, but each connection would be a different slot #, 1-4.
I wouldn't do any UOP directly to the different PLCs in that case but instead block of 4 sections of DI/O. If you need to send the same UO signal to multiple PLCs you can use the flags mentioned before to turn on 4 separate DOs in BG Logic.
Basically flags and BG Logic take the place of your master PLC and each real PLC gets it's own set of Separate DI/O.
I have been playing around with using the robot as opposed to adding additional hardware but I am not sure what exactly you mean by "BG Logic would act like the master PLC". All I want the PLC's in the field to do is provide triggers for when the robot should execute the pick or the place to that machine which are discrete I/O over Ethernet IP.
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Right. Do that in BG Logic, then you don't have to have a PLC.
Master is referring to what controls the robot UI signals. In this case the robot would control its own UI signals thru flags.