Communication Modbus RS485

CODESYS
,
1

Hello everyone,

I am working on a serial RS-485 half-duplex Modbus RTU communication.

I am using a WAGO 750-8112 with CODESYS 3.5.

For the serial interface, I used a MOXA UPort 1150 (USB-to-serial converter for simulation):

  • Pin 3 (R+) of the MOXA connected to pin 1 of the WAGO 750-1652 card
  • Pin 4 (R−) of the MOXA connected to pin 5 of the WAGO 750-1652 card

I am communicating with a Modbus simulator (simulator name).

Unfortunately, I am unable to establish communication with the simulator, whether through I/O check or the API program.

On the 750-1652 card, both LEDs A and E are solid green, while all other LEDs are off.

Do you have any recommendations or suggestions to help me resolve this issue?

API Code:

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image1915×994 74.9 KB

2

In your function block call you have I_Port := COM1

COM1 is the built-in DB9 port on the 750-8112. To use the 750-1652 module, replace COM1 with the module’s name in the project tree.

i.e. I_Port := _750_1624_24