HMI Pad Forums Main Forums General Modbus RTU to Modbus TCP Question

This topic contains 7 replies, has 3 voices, and was last updated by  gregM 3 years, 10 months ago. This post has been viewed 1668 times

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  • #21671

    iMapleInc
    Participant

      Would it be possible to use a Modbus RTU to Modbus TCP Gateway (http://www.icpdas-usa.com/tgw_715.html), wired to (1) Modbus RTU device, then use this app to access the Modbus TCP segment of the Gateway and control / monitor the Modbus RTU register points on the Modbus RTU segment of the Gateway?
      I am looking for a cost effective solution to remotely monitor and control systems in remote buildings, each of which has (1) Modbus RTU RS-485 controller with approx. 15 control Modbus register control points.

      #21672

      gregM
      Participant

        We use something similar from Grid-Connect.

        http://gridconnect.com/industrial-protocols/modbus/modbus-rs485.html

        it works really well.
        We talk to thermostats from http://www.datanab.com to control temperature in a school.

        #21673

        iMapleInc
        Participant

          gregM,

          Thank you. I am using a very similar controller as the Datanab you referenced etc… I only have (1) controller per building / gateway for my current application, but I was wondering how many of the Datanab devices were you able to connect to (1) NET485 module & effectively display on the HMI app?

          #21674

          gregM
          Participant

            iMapleInc,

            I think the max number of Datanab (or Modbus Slaves) devices that 1 NET485 can talk to is 10 simultaneous connections.(10 Modbus Masters requesting Data from Slave devices behind the NET485)
            Other than that limitation, I think the number of modbus slaves is limited to the Modbus RTU Protocol, which is limited to 254 address on one network.
            Displaying the 12 Datanab devices that we used, on HMI View was very doable.

            #21677

            iMapleInc
            Participant

              gregM,

              Thank you again for all your assistance. I am starting on my 1st HMI Pad project today. I was hoping you could clarify something, if you have more then one remote building each one with (1) identical system (1 controller like the one on your school project) with the same Modbus points etc, can you create (1) HMI project and apply it to multiple sites? Each site would have a separate IP address and password, but could same project access code be utilized by multiple sites / customers to access (1) “standard” project?

              Thanks

              #21678

              gregM
              Participant

                iMapleInc
                If you want to deploy the same project to many different customers, you’ll need to do a couple of things.
                1. You would need to have a textfield to change the IP Address and Password in your project somewhere.
                2. I find it more convenient to have separate license codes for customers. 1 customer per code or group of codes.
                3. if you are using modbus, there is no validation tag for that protocol, so you would have to have a single license per user and change the Remote IP Address in the project, and not let the user change it with a textfield. if you’re going to go through a PLC, most have a validation tag to ensure that you’re connecting to the right PLC.

                not sure if I answered your question or not. feel free to give me a call, two one eight -seven seven nine – three four one four.

                #21694

                bdfang
                Participant

                  I am trying to use a wifi to Rs485 to communicate with some devices running on modbus rtu, until now not successful the adapter that i am using is from US Converters model UCW4842

                  • This reply was modified 3 years, 10 months ago by  bdfang.
                  #21696

                  gregM
                  Participant

                    bdfang, you might want to start a new thread with this question.

                    I have a couple questions,
                    what are you trying to connect to? what’s behind the UCW4842?
                    there are a bunch of settings that would have to be correct in order for this to work.
                    what have you tried so far?

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