Communicating with Device over Modbus RS 485 and TCP/IP


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I am working with a TGW-715 Modbus gateway which is connected to a Modbus device.

Modbus device is configured with following parameters:
-baudrate 9600
-modbus enable
-adress 1
-parity none

And I also configured the gateway with these parameters.

I connected the D1+ and D1- of the gateway to B and A of the Modbus device.

But when I want to test if everything is working on Modbus Doctor, I got the exception code 0B which means that there was no response from slave.
I tried to increase the timeout to 3000ms but still get no response.

Do you have any idea why?

Change the A and B driver line connections on one end.

The labeling of the lines is not standardized. If connected backwards, it won't damage the drivers but it won't work.