KRC2 ED05 X11 Connector Unexpected Behavior

    Hey all,

    TLDR:

    The X11 safety interface on my KRC2 ED05 controller does not match the cabinet documentation and behaves unexpectedly.

    Background:

    I have a KR360-2 with a 7th axis and a KRC2 ED05 controller. The robot is fully functional with no error messages, and we have been using it for the past several months. I am trying to hook up an external EStop through the X11 interface, and am following the typical X11 documentation for my controller: BA KR C2 ed05 V5 en (Kuka ID: PB4846).

    My warehouse has a KR 1000-F titan with a KRC2 ED05 controller and an X11 interface. I have successfully integrated an external EStop, drives activation button, safety gate, etc. I have some experience with the X11 system from this, and a working system to test out hypotheses.

    Issue:

    The X11 jumper currently used on the robot is odd - Some of the pin pairs that the manual says must be jumpered are not jumpered, while other pin pairs that aren't covered by the manual are jumpered (further details in posts below). However, the KR360 accepts it without any errors.

    When I hook up an External 2-channel estop to the connector (1 -> 4, 19 -> 22), the robot does not change behavior. There is no acknowledgement of the Estop at all.

    Hypothesis:

    The documentation mentioned above mentions multiple possible C13 boards that could be installed in the cabinet.

    • KR 1000: C13 Tech Board (This is the one that works as expected)
    • KR 360: C13 Bus Board (This is the one that doesn't work as expected)

    According to the documentation regarding the C13 Bus Board:

    Quote from KRC2 edition 2005 Operating Instructions

    The SafetyBUS p Gateway board is plugged onto the CI3 bus board and connects the ESC circuit with the SafetyBUS p manufactured by PILZ

    This implies (to me) that the C13 Bus Board could be modifying the safety system operation. Unfortunately, referencing Kuka's documentation for SafetyBUS Gateway (Kuka ID: FI3663) contains no mention of the X11 interface

    Edited once, last by robonovak (August 18, 2021 at 6:47 PM).

    Wiring Diagrams:

    The following are two wiring diagrams of the X11 configurations in question.

    KR360 (C13 Bus Board):

    Notes:

    • Several undocumented pins (13 - 16, 31 - 34, 84 - 85)
    • Seemingly no need for "required" jumpers (41 -> 42, 38 -> 50, 39 -> 51)
    • Estop shown does not work.

    KR 1000 (C13 Tech Board):

    Notes:

    • Includes all "required" jumpers
    • No undocumented pins
    • Estop shown works as intended

    You didn't mention much detail -- what error messages is the KR360 throwing? Is it joggable in Teach?

    You have to close the DRIVES OFF channel, and the External Enabling channels. The Safety Gate channels are required for AUT/EXT, but ignored in T1/T2.

    The exact wiring isn't absolute: for example, your Titan connects Pin1 to Pin4, while the example below connects 4 to 3, and 1 to 2. The requirement is that a "Test A" output must be wired, through your safety gates/buttons/etc, to an IN A input, and Test B to IN B. Which Test A/B output doesn't really matter -- all the As are the same, as are the Bs. But you cannot cross an A with a B.

    SkyeFire you're right, I should have been more specific about the behaviors.

    The KR360 jumper came with the robot when it was purchased, I did not build it. The KR360 functions normally with no error messages when the connector shown in post #2 is plugged in.

    The EStop pictured with the connector in post #2 does not estop the robot, and no additional messages display when it is pressed. The robot acts as if there is no external EStop.

    Quote from Skyefire #3

    You have to close the DRIVES OFF channel, and the External Enabling channels.

    I am inclined to agree with you, as the Titan requires that jumper - when it is removed, the drives will not activate. However, the KR360 requires no such connector, and you can activate the drives as normal without it. spoooky . . .


    This odd behavior is repeated with the other jumpers you mentioned - it's as if the X11 interface on the KR360 requires different jumpers than the interface on the KR 1000.

    As far as I'm aware, X11s should be standard across KRC2ed05 cabinets -- in fact, they should be standard going back to the KRC1, generally, except that more channels were added over time. Normally, KUKA changed the label on any "off standard" version of X11 -- GM KRC1s, for example, had "CC1," and I think Daimler KRCs had a different unique safety connector replacing X11.

    So if it's labelled X11, I would normally expect it to be standard.

    What kind of hardware does the KR360's KRC have internally? I don't recall ever seeing a KRC2 with an X11 such as you describe, but I have seen some that had safety relays installed in the bottom of the cabinet, and those relays were wired "between" the X11 and the ESC board. It was an early way of getting "network safety" before SafeOperation was available.

    Did this KRC come with the original KUKA internal electrical drawings? If there was a safety relay option package installed from the factory, the KUKA electrical diagrams should show them. If you don't have the drawings, KUKA is usually pretty good about providing the "as delivered" prints if you give them the robot's serial number.

    SkyeFire

    Good things to reference and look for, thanks. I'll go do an inspection of the safety hardware in the cabinets either today or Monday, and peruse our electrical diagrams.

    I also intend to systematically remove each of the unknown jumpers on the KR 360 and look for error messages that could point me in the right direction. Will update here once that's complete.

    Quote from robonovak

    SkyeFire

    Good things to reference and look for, thanks. I'll go do an inspection of the safety hardware in the cabinets either today or Monday, and peruse our electrical diagrams.

    I also intend to systematically remove each of the unknown jumpers on the KR 360 and look for error messages that could point me in the right direction. Will update here once that's complete.

    The systematic approach is always good. I once had a bad X11 jumper that threw no errors, let the robot run in Auto, but prevented me from getting Drives On in T1 mode. Eventually I only found the problem by swapping my X11 jumper plugs around between robots, zeroing in on the "bad" jumper as the problem, then ringing out every wire on both the "bad" X11 and one of its "good" siblings, until I found the one wire that wasn't crimped properly.

    If your KRC2 has a KUKA-option safety relay package installed, it'll most likely be located on the DIN rail at the bottom of the main "backplane" inside the KRC, below all the servo modules. The ones I saw the most of used ProfiBus, although ProfiNet/ProfiSafe and EthernetIP/CIPSafe are also possible.

    Normal practice was to have the robot non-Safe I/O share the bus with the Safety bus -- so the ProfiBus, for example, would enter the KRC2 and "daisy chain" to the safety module, then to the robot ProfiBus I/O card (or vice versa), then usually daisy-chaining back out to another connector on the KRC2 lower bulkhead. This is due to PB being a multi-drop bus, rather than a network.

    EthernetIP and ProfiNet were relatively rare on KRC2s, as the KRC2 was approaching end-of-life when those networks started to really get popular, but not unheard of.

    And just to counter my own statement, I did recently see a KRC2 where someone had set up PB just for the safety relay module, but had all of the non-Safe I/O running over DeviceNet.

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