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How to connect RS485 from PLC to uLCD-PT32(GFX) UART

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  • How to connect RS485 from PLC to uLCD-PT32(GFX) UART

    I am new to uLCD-PT32(GFX).
    I would like to use this device as a UI control for Nano-10 PLC (From Triangle Research International) which has RS485 connection. Supported Protocols : Native ASCII Host Link Commands (programming/monitoring); MODBUS RTU, MODBUS ASCII; Default COM speed 38,400 bps, may be set from 1200 to 115.2K & 230.4K bps.

    Please advice me on the a/m and the hardware need, thank you very much.

  • #2


    The uLCD-32PT has TTL Level UARTs on board, so you will either need to buy or build a suitable UART to RS485 interface.
    Without seeing the details on the protocols its hard to know which is best, or what you actually want to do for that matter.

    We have an example application going back a few years, which implemented a Modbus RTU protocol in 4DGL. If you like, I can try and find it for you.

    Before years end, we will be releasing new modules. One range of these modules has daughter boards (4D Mates) available (will be coming out early Q1 2013), and one of these 4D Mates is an RS485 interface for the display module.
    So depending on the timeframe for your project, it might be suitable to wait for the new display modules and daugter boards, and implement your system using those.



    • #3

      Hi James,

      Thanks for your reply.
      Can I have more information on this new display modules and daughter boards with RS485 interface, especially dimension and unit cost. As well I like to see the example you had mentioned too if it still available. Thank you very much.


      • #4

        Hello, I would like to use a GE MT96 power analyzer modbus RS485 with a Godelox uLCD 128. I using a Max485 transceiver TTL to 485 levels. I’m interesting in to get your example application using Modbus RTU protocol in 4DGL. It’s possible to get your code?.



        • #5

          Please can provide me the sample code?