Bypass mastering reference switch KRC4 KR120 R2500 PRO

  • Hi all,

    I was wondering if anyone has experienced the following issue,

    We bought KRC4 KR120 R2500 with PROFINET (profisafe), SAFE SINGLE BRAKE as an optional package. Along with a KP3H2H750 external axis.


    Interestingly enough we got a mastering reference switch as the one in Kuka. SafeOperation manual but no where on the whole machine to physically plug it into. 😐


    So my questions are,


    How do I programmatically disable/bypass the mastering reference switch completely?

    ($MASTERING_REF_EXT is currently assigned to always true by default)



    Is there a system variable to adjust the external axis acceleration and deceleration? It works fine but I think it's ramp up and ramp down are too aggressive so I want to make it smooth.

    (already tried $ASYNC_AX_FLT to make it smooth )


    Any help appreciated.

    Cheers

    Nar

  • login as Safety maintenance

    go to safety configuration

    turn off SafeOperation

    Hi panic mode, I Looked at it only safe monitoring available which will disable the reference switch but is also disabling my safe single brake option as it monitors for axis's under the defined axis group to be in stand still if triggered and issues an SBH. (safety stop for axis group 1...6).

  • Hi panic mode, I Looked at it only safe monitoring available which will disable the reference switch but is also disabling my safe single brake option as it monitors for axis's under the defined axis group to be in stand still if triggered and issues an SBH. (safety stop for axis group 1...6).

    So, you want to keep SafeOp, but bypass the Mastering Reference switch?


    If the robot came with a MasRef sensor, there should be a socket on the KRC4 to plug it into -- usually right next to the pendant socket. Is this missing? You may want to check the options this robot was ordered with.


    One alternative would be to change the SafeOp MasRef option -- there is an option to either use the directly-connected MasRef sensor, or to receive the MasRef sensor input over ProfiSafe or EIP (whichever you're using) from a Safety PLC (there's a dedicated safety signal for that).


    But be aware: you can't just fake this signal -- the MasRef program expects to see that signal change states, relative to the MasRef position, and leaving it True or False too long will generate safety errors in the KRC. And faking it would almost certainly violate RIA safety standards, anyway.

  • Hi skyefire,

    You are absolutely right. We only ordered the robots with safe single brake. And funny they should send us a mastering reference switch with no physical port to plug it into none of the 3 controllers had the port to plug the ref switch.


    Information received from kuka support is pretty slim at the moment.

    They told us to force safe signal from PLC for mastering reference switch JR and after 350ms pulse another safe signal EJB to clear the issue but I don't have the EJB signal in my safe inputs.

    Any chances I could do it in the masterref_main.src program where it checks/implements the switch checks and cheat it to bypass. Because after the elapsed time the sensor trips the external cell running and had to confirm msg and then start cell again.


    Cheers

    • Helpful

    just get X42 interface and mount it yourself or let Kuka do it. it is just a one small connector to CCU and 4 screws to mount the pass through bulkhead at the cabinet front. it installs next to X19. if your robot was ordered with SafeOp, this interface should be installed at the factory. but if SafeOp was added later on someone forgot to go through checklist and add it later. check your delivery note and quote it X42 was ever mentioned. normally this is only omitted if controller is KRC4 compact (no room to mount it) or if client insisted on not having it or there was a mistake. worst case you will need to shell out $100 or so (whatever they charge for this thing)

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

  • The JR signal should just be connected to the MasRef sensor -- you wire the MasRef sensor to a safe input pair on the safety PLC, and have your safe-PLC program pass that signal directly to the robot on the JR signal. I don't recognize this "EJB" signal they're talking about, either.


    There's no way to fake this in any of the robot programs, b/c the safety controller in the KRC4 is essentially a separate "brain" of its own that is inaccessible from the "main" controller. The MasRef program works by setting an internal signal that tells the safety controller to check the MasRef input and the robot's current position (vs the MasRef position set in the Safety Config). And if the safety controller doesn't see what it wants to see, it fails the MasRef test.


    Likewise, if the MasRef input (hardware or JR) stays on too long, or not long enough, it's a failure. So the JR signal has to come True, and then go False, at the right location, within the right time frame.

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