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Codesys + Raspberry + Arduino via Modbus TCP

jru
2018-05-29
2018-06-19
  • jru - 2018-05-29

    Hello everyone.
    I encountered a problem reading the modbus TCP registers in Codesys.

    Registers are correctly read in eg. ModbusScanner, but in Codesys I can not read any values.

    I am trying to read eg. Input Register offset 100.

    Due to this difficulty I can not continue the project, I am asking you for help in configuring Codesys. What to do to read anything over Modbus TCP.

    I'm attaching a program file in Codesys and Arduino Uno with Ethernet Shield.

    Sample of code for Arduino:

    //Modbus Registers Offsets (0-9999)
    const int SENSOR_IREG = 100;
    //Used Pins
    const int sensorPin = A0;

    I will be grateful for your help, greetings. !!!

    IMG: Bez tytułu2.png

    IMG: Bez tytułu.png

    RPI1_1.project [194.35 KiB]

    RPI1_1.project [194.35 KiB]

     
  • juan356 - 2018-06-04

    Hello. I made the same like you but with MODBUS RTU using a max485 chip to convert ttl signals to rs485 standard (plug on pins 0, 1 and 2 on arduino pcb)and the usb port from the raspberry pi. It works very well.
    Maybe you have a problem with the number of register to read. I think arduino can't stor on its buffer more than 64 words.
    As I told you before, my system with four arduino hanging from a raspberry pi serial port works very well, even if I turn off any arduino pcb it continues working.
    BR

     
  • jru - 2018-06-19

    hello juan, thanks for yours advice!

    for me, the solution was different.
    I used the 28j60 ethernet shield model and there was a problem.

    I bought a classic shield Ethernet "Arduino Ethernet shield R3 with micro SD connector"
    like this:
    https://botland.com.pl/produkty-wycofan ... crosd.html

    and the connection worked!

    Settings:
    for input register code 4
    for register 100, enter offset 0x0064 in the channel

    The whole works perfectly with raspberry pi 3 B +

     

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