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P3000 and SCM intercommunications

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  • P3000 and SCM intercommunications

    We have a P3000 ( P3-550 CPU) panel talking to some 3rd party drives via Modbus RS-485. P3000 is the master
    The P3000 also will be connected to a CMore EA9 via ethernet. C-More is the master

    We need to have multiple P3000 panels talking on an Modbus RS485 bus to a SCADA system. It was suggested by tech support to use a SCM card to get another RS485 port that would also allow the P3000 to be a slave.
    We already have all of our tags setup as modbus points in the P3000. How do I set things up so the SCADA system can access them through the SCM? Is there anything we need do other than set the communication parameters?

    Also, both the SCADA and C-More will be read / write. Do we need to be concerned about potential conflicts?

    If there's a better approach to this, we're all ears.

    Last edited by JackW; 03-05-2020, 02:29 PM.

  • #2
    I dont really know what SCADA you are using, but generally, when I think of this it runs on a PC and is on a network. If possible, you probably will want to connect all your PLCs to the SCADA system via Ethernet for greater speed, reliability, and ease of use. You also already have an ethernet port on the P3k, so no need to buy another SCM module.


    • #3

      Thanks for the response.
      I probably should have clarified that modbus TCP / ethernet is not presently an option which was why we were buying the SCM.
      The customer has an RS485 panel (what they call an AEMS) at each location that ties back to their SCAD system.

      I just don't understand how I will access the modbus registers in the P3k from the SCADA. Do I need to map them to the SCM or does the SCM just provide additional ports and everything reads and writes from the P3K ?



      • #4
        Hi Jack,
        You mentioned that the Modbus addresses have been already programmed. All you have to do is set the communication parameters. The Client (Master) will request the read /write to these locations. Your CPU will respond to the request and send /write the information.
        As with the scan of the PLC, the last request will win. If the SCADA and C-More are writing to Modbus address 40001, the last communication will be the one placed into the Modbus address.

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        • #5
          Great! The SCM just passes the request to the CPU. That exactly what was I was hoping for.
          Thank You