SAFE I/O Connect

    Hello everyone,

    Thank you all for the previous support I couldn't have got this far without it!

    My next subject is about the Safe I/O connect.
    The cell I am working on is still being commissioned, we are using a laser cutter as our tooling we've realised that when DCS is triggered it also puts the laser head into E-Stop which is not going to work for us as it's a process to get it started again.
    What we want to do is when DCS is triggered it ONLY switches the laser off so for example cut the supply to the laser rather than E-stopping it. Luckily enough the Robot was specced with the Safe I/O board so now we just need to figure out how it works.

    I think i have the basic idea but i think i need some clarification!
    So as far as I'm aware i need to basically set a fresh DO which will be the trigger to the PLC to turn the laser off.


    So for example above I set my safe output to 1 (SPO) (ignore the 17) which means when that is triggered by my CPC 8 (DCS Zone) it will then send the signal to the PLC to switch off a DO that's connected to the laser.
    Thank you in advance for any help, I hope I explained this well enough!

    I think you need to clarify a few things:

    What is E-stopping the laser, an external controller (PLC)?
    Why is an E-stop being sent to the laser?
    Should the robot be able to issue a request to E-stop the laser, and if so: under which circumstances?

    You might have to invert the logic (always get this mixed up) so that the SPO is 1 as long as the laser should be energized. I think that the CPC-status signal is 1 as long as it's considered "SAFE", which differ depending on how you set the CPC up (Inside or Outside).

    Thanks for the response!

    Sorry - I got it completely wrong, it doesn't E-stop the laser continues to fire regardless if the robot is in DCS or not which is why it's quite a dangerous situation.
    I'm getting 2 systems I work on muddled up!

    So what we need to happen is that the safe I/O would send an output (SPO1) to a safety PLC when a DCS zone is triggered when this happens the Safety PLC will then cut the supply to the external laser source (not controlled by the robot). So from my understanding on that image I posted on here it would be something like this as an example:

    OUTPUT INPUT 1 INPUT 2
    SPO [1] = CPC [1] OR CPC [2]

    So when CPC 1 or CPC 2 is triggered it sends a safety output (SPO1) to the safety PLC have I got this correct?

    The PLC is being programmed by someone else and will just go with whatever we set it at. I beleive SPO1 is pins 11 and 21 (I think)

    Thanks again!

    Hi,

    You are correct in your understanding of how it works. However, the criteria for setting CPC 1 or CPC 2 to TRUE will vary depending on how you set those CPCs up (whether or not it's defined as "Inside" or "Outside").
    Normally, when dealing with safety-related functions, TRUE, 1 or ON means that something is considered "safe".
    In your case, with your CPCs, one of them may be set up so that the robot (or rather the laser) should keep out of a certain area. As long as this is fulfilled, the status output should be TRUE.
    Or, you might have it so that the laser must not exit a certain area, and as long as it is inside that area, the CPC status output will be TRUE.

    You might also want to look into the orientation check function of DCS, seeing as you are working with a laser... What if the laser is at an approved position, but it is pointing in a dangerous direction?

    The orienration check on robots that handle laser guns is a must, no one wants to get blind because someone made an error and the robot reoriented while active.


    Also, in order for the laser desactivation to be effective, being using an e-stop signal or a shutter closing signal, all signals used must be safe, so if the signal that triggers the laser output is a normal DO, it's not safe. If it is triggered from the plc and it's done in the normal program it's not safe, if it's handled on the safety program and it triggers a normal do instead of a safe output, it's also not safe.

    For this to be safe it should be wired to the shutter interlock, the robot can send the laser output using a normal do, but some safe signal should be wired using the dcs and orientation check so the shutter or the power supply is powered off if robot leaves the area or reorients out of the welding/cutting orientation or area.

    At least this is how things were done when I worked with laser welding or cutting guns on every installation I worked.

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