Why isn't my Modbus communication working over RS485?

26 Jul 2022

 

This article describes why the Modbus communication does not work over RS485. 

 

APPLICABLE PRODUCTS 

Ewon Netbiter 

 

QUESTION

Why isn't my Modbus communication working over RS485?

 

ANSWER

Often there is a problem with the wires. First thing to do is to check that the A and B lines are connected properly. Next thing is to switch the A and B line and see if it works. For the Netbiter A is + and B is -. Other things to troubleshoot are the Modbus communication settings on Argos, baud rate, parity, stop bits, slave id etc.