Parameter setup Modbus TCP between GW1420 and ABB 800xA

I would like some feedback from anyone that have experience in setting up modbus tcp communication between an Emerson 1420 and ABB 800xA system. I use plc connect and got communication running but only the register value updates and not the PV, it´s 0. Perhaps there is an easier way to communicate, OPC perhaps. There must be some reason why ABB are using P+F GW instead of Emerson GW.

1 Reply

  • HI,

    The use of Modbus TCP is really simple.

    Check that the PLC is Modbus master (Modbus specification master, TCP it would be client) in other words sending out the queries to the Gateway.

    The gateway acts like a SEVER it gives values according to the queries. (also called Modbus slave, to make thing difficult)

      I will give you some key points to check.

    Check that these parameters are OK, swapped bits depend on the "big/small Endian" on the reading side.

    To read the values, open the Modbus register Map.

    You have to manually enter the desired values you want to read... PS. 32 bit float requieres two registers.

    1. Navigate to the Modbus Register map section on the interface. Click the New Entry button to add a new monitoring point.

    2. Under the Point name for the new entry click the “…” button to get a dropdown list of common values to monitor. ( Tagname , PV, SV, TV, QV)

    Double click on your choice.

    3. Use registers starting from 40001(16 bit holding register), each 32 bit value requires two 16 bit registers, so the register numbering should step by 2.

    4. Repeat steps 1 and 2 for each value.

     When finished, click submit

    Also check that the Modbus TCP port is open under ..Setup>Security>Protocol.

    OPC is usually meant for PC-type connections and aren´t included in lower level communications like PLC...?

    OPC is as easy to use as Modbus...

    If you have any more question just ask Cool

    Niklas Flykt 

    Klinkmann Oy

    Key Account Manager safety products

    nikfly@gmail.com