adding additional safety IO to KRC4

    Hello, I am quite new to this so bear with me please.


    I am planning on using a KRC4 primary controller connected to EK1100 -> EL6695-1001 -> (Safety stuff). Would this be sufficient enough to add extra SAFETY IO without the addition of the X11? namely I want to add Estop and light curtains without needing to purchase the expensive x11/x13 to add the extra safety IO.


    I am thinking of two different options if this doesn't work namely:

    KRC4 -> EK1100 -> EK1918 -> (safety stuff)

    or

    KRC4 -> EK1960-0000 -> (safety Stuff).

    I am not sure which one of these would work as I am very very new to this. I don't think I need access to the secondary side of the EtherCAT, however i am unsure and any advice is appreciated.

  • 95devils

    Approved the thread.

    not familiar with EK1960 but i would say that is probably not how things work....


    when working with a fieldbus (any kind), one can connect two or more nodes. but... that is not enough.

    one of the connected nodes needs a special role - it need to act as a bus master. other nodes are slaves. Master initiates and controls communication. slaves can be specialized but they are still 'dumb' in a sense that they do not understand surrounding or what other nodes exist near them. they only respond when spoken to and the "conversation" is controlled by master. master keeps a list of all slaves, their IO range etc. so master can talk to any of (own) slaves. master does not see what is on the other side of the bridge. bridge simply appears as another (own) slave.

    EL6695 is a bridge - it is used to connect two different bus networks. master on each side of the bridge only sees one side of the bridge. bridge swaps traffic lanes. data arriving from one master is available for other master to read and vice versa.


    in other words network on each side of the bridge needs own master.


    on one side there is a KRC and that is fine for that side.

    but the other side of the bridge needs a network master as well (fieldbus master). one of CX8xxx or CX9xxx CPU would fit the job. They just cannot do safety control.


    in case of many PLCs, same CPU is used as fieldbus master, standard controller, as well as safety controller. but with Beckhoff line of products, standard CPU is used as a standard fieldbus master and standard controller (non-safety) but it does not work as a safety controller. role of safety controller requires another product - this could be EL6910 or similar (several candidates exist).


    EL1918 is actually safety input module but... it also has a small safety controller in it, which can be used in place of a dedicated controller like EL6910. note that you still need standard CPU because it handles all the other things (fieldbuses, project transfer etc.)


    EKxxxx are bus couplers. an example of this are EK1100, EK1110 etc.


    as already stated i am not familiar with the EK1960 but from what i could glance over, this unit seem to support dual role - it can work as a bus coupler (can connect as a slave to a bus that has master) and it can work as a safety controller. in standalone mode, it works like small safety PLC (just using local IO) but it does not look like something that can initiate communication or access distributed IO over the bus.


    so for a small system using FSoE you probably want to look at:

    a) smaller CPU like CX8xxx

    b) one or more of EL1918 (safety inputs, plus one of them can work as a safety controller)

    c) one or more of EL2904 (safety outputs)

    etc.

    (you can add standard IOs as well)


    that is pretty much what the "other" side of the bridge normally looks like.

    on the KRC side it would be EK1100+EL6695-1001 (and maybe other IOs if needed)

    the EK1100 connects to KRC and this acts as interface to primary side of the bridge.

    the RJ ports on the bridge are secondary side and this is what CXxxxx connects to.

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    I thank you for the detailed response, this was very helpful in clarifying the Beckhoff and KUKA communication along etherCAT and FSoE.


    I think the system we are planning to go with now consists of the following devices:

    Primary:

    KRC4 -> EK1100 -> EL6695-1001 -> CX5120


    on the secondary side CX5120 will connect to the EL6910, EL1918, EL2904, EL1008, EL2008, EL3164 for safety PLC, Safety IO, DI/DO IO and Analog input expansion.


    I talked to the Beckhoff Technical support and they suggested the CX5120 versus a CX8xxx since we can run a windows based HMI on the PC as well as program the PLC and can potentially do MODBUS communication as well, Are you able to provide any insight on how the MODBUS integration works with these Beckhoff CPUS? is it just a software library that we need to utilize or am i mistaking the technical document on their website??


    Thank you so much for the time and help.

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