KRC5 micro connection with Beckhoff PLC

    Hey guys :smiling_face:

    Component list that we already have installed in our system:
    KRC5 micro
    KR10 K1440-2
    Beckhoff EK1100 Ethercat coupler
    EL1008 & EL2008 I/O modules
    Beckhoff C6930 PLC
    We have already successfully managed to map the outputs of the EL2008 module to the KRC digital outputs with Ethercat communication through the EK1100 coupler. Our task would be to establish communication between our Beckhoff PLC and KRC5 with Ethercat so that we would be able to control the IOs with the PLC and receive them in the KRC5 and vica versa. What are we missing to be able to establish communication, how can we set this up?Are we missing the EL6695 Ethercat bridge because by our knowledge it is not built into the KRC5 unlike the KRC4 or maybe we don't need an EL6695 and the EK1100 and IO modules are enough?Help would be greatly appreciated as it proving to be a challenge to make this work.:neutral_face:

  • MOM June 12, 2024 at 10:41 AM

    Approved the thread.

    first you need to determine what you need and what the nodes are capable off. for any node to be a part of the network, it must support that network (in this case EtherCat) and the suitable role in that network.

    role can be master or slave (and in some cases - both). the minimal network is where one node is a master and another node is a slave. master to master does not work. slave to slave does not work.

    KRC can act as EtherCat master.

    when PLC (or PC) is also an EtherCat master, you must use a bridge. Bridge allows two networks to connect (bridge acts as a slave to each side, basically allowing two masters to have their own networks).

    When PLC (or PC) is capable of working as EtherCat slave, then bridge is of course not needed.

    Beckhoff C6930 is not a PLC. it is a compact PC. not sure if it supports EtherCat and in what capacity and on what ports. it is a higher end controller so it has plenty of muscle. this means even if the hardware ports are not natively support particular network type or a role, there is a good chance that this can be added as a software option.

    but... there are some other concerns too... are you planning on using FSoE? in that case you must use KUKA bridge EL6695-1001. and your PC (PLC) will also need FSoE controller such as EL6910 and safety IO.

    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

    Ultimately our task would be to establish a duplex communication between 2 KUKA KR10 K1440-2 with KRC5 micro controllers trough EtherCat protocol so that we would be able to control the two robots separately with one Beckhoff PC (in our case refered as PLC) .


    We know that it is possible because we already have in our posession a working cell with two of the same KR10 K1440-2 robots the only difference being that those have a KRC4 controller. We did not create this cell that is working, it has already came finished, but we have excess to all the software and hardware settings and we created our the same way as that is.

    One issue that we are aware of, is that the KRC5 micro controllers need to be set up as SLAVES to be able to communicate with the Beckhoff PC (that would be the MASTER in our case) as you already mentioned, but we did not yet find a settings to set these controllers as slaves.

    Is it possible to set it up the controllers as slaves or do we need an EtherCat bridge ?

    Thank you for the help panic mode, in the end we temporary removed the bridge from our KRC4 installed it in the KRC5 and the connection seems to be working, we are able to send inputs to the KRC controller from the PLC. (the topology is KRC5 -> EK1100 -> IO modules -> EL6695-1001 -> PLC, hope this is right but it looks to be as it is communicating).

    Next task is to figure out the FSoE safety as it won't let us move the robot. If we understand this correctly a safety module will be needed like a EL6910 or EL1918 and set these up in our PLC program and it should be working after that with no more safety errors, right?What variables, IOs should be handled in the PLC exactly?

    read manual for SafeOperation... there is a detailed info on signals t higher level controller. if your robot does not have or does not use SafeOperation, you only need to handle the basic safety signals. they are the first 16bits (two bytes) of safe inputs and 16 bits of safe outputs. unfortunately doing this in TwinCat is not very straight forward so you will need setting up the safety I/O since they are transported by main CPU (PC/PLC) but need to be passed on to safety controller. for small programs you do not need EL6910, you can use one of safety IO modules as safety controller.

    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

    Hey, my setup has changed a bit, my topology is: KRC5 to EL6695-1001 to and the EK1100 to PLC so KRC is connected to second side and plc to primary. My problem is I want to change the IO size, it is 4 byte by default and I'd like 128 bytes. If I change it in secondary side -> modules -> std.io128bytes and upload it to krc I get sys-x44 error KS13018 invalid device setup. With 4 bytes of data it is working, what might be the problem?

    I have robots talking to Beckhoff all the time using the hardware you just described.

    I assume it looks like it does below:

    Changing the data size will mean that the Beckhoff settings for reading / writing from the 6695 will also have to change. (Keep in mind with EtherCAT is a hardware layer protocol which loosely translates into it being more finicky to setup)

    All that being said, if you're set up like this in WoV, your error must be in TwinCat.

    Edited once, last by work_BR (June 14, 2024 at 6:51 PM).

    Quote from work_BR

    I have robots talking to Beckhoff all the time using the hardware you just described.

    I assume it looks like it does below:

    Changing the data size will mean that the Beckhoff settings for reading / writing from the 6695 will also have to change. (Keep in mind with EtherCAT is a hardware layer protocol which loosely translates into it being more finicky to setup)

    All that being said, if you're set up like this in WoV, your error must be in TwinCat.

    I had it setup this way the first time, now my setup is: KRC4 secondary in WoV and KRC4 primary in TwinCat 3, the reason being that if I have it setup your way then I need to setup FSoE too which I don't need right now. I need to be able to send data with it setup in WoV as secondary and in Twincat as primary if that is possible.

    Quote from work_BR

    I guess to throw you a quick bone despite this not being TwinCAT forum:


    There's a button to load from device, but i find that it doesn't work all the time. Select the PDO assignment that matched the size from the list.

    Yep, I did find this setting and set them to the right sizes but still getting the same error.

    Actually if I have it on anything other that 4 bytes, it doesn't work somehow.

    Quote from industrialBanana

    I had it setup this way the first time, now my setup is: KRC4 secondary in WoV and KRC4 primary in TwinCat 3, the reason being that if I have it setup your way then I need to setup FSoE too which I don't need right now. I need to be able to send data with it setup in WoV as secondary and in Twincat as primary if that is possible.

    I have never setup this connection without FSoE, I don't know if you can? The safety section in WoV must be enabled somehow I assume? Like the KR C will not let you deploy something without safety enabled? Therefor your error is because TwinCAT does not have safety but the KR C does? Weird that 4 Bytes works i guess... I might not know enough on the subject to say why.

    FSoE is not needed if the KRC has other safety interface (X11 or CIP safety or ProfiSafe). in that case bridge need to only pass standard signals. standard signal should pass through any bridge in both directions as long as setup is correct. but when safety signals also need to pass, bridge need to be EL5595-1001 (from Kuka) and primary side need to connect to KRC.

    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

    i find it odd that often topic starters do not share any screenshot of his own setup. i would always expect to see more details including

    a) what is the plan (what safety interface is used, which side connect to what...)

    b) what is the attempted implementation (actual physical connections, actual settings that follow the plan... both the KRC and PLC side)

    c) how is this tested? what steps are taken exactly? did both nodes get restarted?

    i have seen cases where plan was one thing but implementation is something different entirely. common mistakes include connecting to wrong ports (just jam the cable into any port that fits, regardless if that is the correct port for the application), not doin mapping, doing wrong mapping, attempting to assign wrong role to one or more devices, not powering the devices etc.

    in this case TS did manage to get some data exchanged... this indicates that many of the pitfalls are sidestepped. (power, ports, connections, IO mapping, software versions etc seem to be fine).

    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

    I can make some pictures of the setup we are working with tomorrow.

    The plan is to simply establish communication between the robot and beckoff plc and exchange data, variables, toggle the IOs of the KRC with the PLC or vica versa, give feedback to the PLC that for example the program is finished etc. This is it so far, nothing major. We have X11 on our KRC which is working so technically FSoE is not needed right now, but if we could maybe set it up somehow that would be great.

    The actual connection looks like on the pic I attached, some explanation:

    Implementation 1:

    The KRC is connected to the Primary side while the PLC is on the Secondary side, we have a EL6910 in this setup for safety, we can toggle some inputs/outputs but have the robot in safety stop with the red bar on top because FSoE is not configured, we have no idea how to do that what variable needs to be set and to what and when that is the reason we've tried Implementation 2.


    Implementation 2:

    The KRC is connected to the Secondary side and PLC is the Primary side, we have no need for the EL6910 safety module and we are using the X11 as the safety interface which is working so we get no safety stop and red bar. With this the problem is that we cannot the the KRC(secondary side) to more than 4 bytes of IO data, as soon as we change it to for example: 64 bytes, 128 bytes also change it on the PLC(primary side) too so both sides are sending/expecting the same amount of data we get a SYS-X44 error KS13018 invalid device setup. Both nodes were restarted, checked with different cables, we have multiple EK1100s so we tried all, the PLC and the KRC side for us at least seems to be correct in this implementation so we really don't know what to do right now.

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