Interlock robot

What version of controller? If they are older robots, you'll need the space check software option, on newer robots it's called interference check. There are two levels of interference check, basic and intelligent. Unless your robots are on an RTU, you will probably be okay with the basic version.

There are other ways to setup interlocks, such as using reference positions, dcs zones, and just basic I/O handshakes, but none of those is as fool-proof as space check. With space check all you need to do is setup the zones where the robots could collide with each other. That's it. With any other method you'll have to have absolutely bulletproof code that has been tested through all permutations of how an operator could try and start the system.

Space/interference check isn't cheap, but it saves hours of program setup and testing, plus, it just works.

I suggest using Space Function, or Dual check Safety function. it way easier than just using I/O basic configuration for Interlock.

For the current robot model and controller, space function is a basic option for the robot. and DCS is an option function software.

I may be wrong, but Space Check only tracks TCP, not the MODEL of the Robot like Interference does...so beware when programming your robots close together! i.e. Make sure your TCP leads into the area you want to safeguard.

I have same type of project. Most likely I will use Basic Interference Check and DCS options to make sure that nothing on the robot's way. Honestly I can make it done with DCS and RIPE Interconnect / PLC, not sure that I need Basic Interference Check while I have DCS.

If you have robots in same cell right next to each other, and they have communication b/w them, then you can enable a DO saying "robot in area, do not allow other robots to enter". Then all other robots if they want to enter that area, then must wait for the equivalent DI to become false. Once it's false, then other robot can enter the area and turn on it's own DO.

This method should work if you don't have any of DCS options available.

Quote from alive15

If you have robots in same cell right next to each other, and they have communication b/w them, then you can enable a DO saying "robot in area, do not allow other robots to enter". Then all other robots if they want to enter that area, then must wait for the equivalent DI to become false. Once it's false, then other robot can enter the area and turn on it's own DO.

This method should work if you don't have any of DCS options available.

I would recommend using at least a Robot heartbeat signal, or a signal handshake between robots in conjunction with this method. It's pretty easy for a programming error, network problem, or electrical issue to crash robots if you're only using a single digital input.

Are robots communicating to plc via ethernet or hard-wired signals? Either way, if you can get them to communicate a few signals b/w them, you may could get it to work. I only have two robots in one cell, so you may have difficulty with extra robots. Get the robots to look for the correct DI's and include what Erik mentioned also with the heartbeat signal so the robots know that comms are good b/w each other.

It may take some extra i/o for you, so if that option isn't available, then DCS or space may be the better alternative as mentioned.

The proper handshake for "interference zones" is as follows: Robot shall have a "clear of zone x" signal which is held high. A robot which needs to enter should turn on an output requesting to enter zone x. The PLC should look to see that no other robot is requesting the same zone and that no other robots are currently in said zone. If conditions are ok, the PLC grants the request. The requesting robot turns its "clear of zone x" output and request bit off, then moves into area, performs its work, then leaves. When it has cleared the shared area, it should turn the clear signal back on. Also, make sure that you move to a FINE point which is clear, then turn that output on. FINE point is because you do not want the read ahead to turn it on too soon, before the arm is really clear.