Channel 0 RS485 modbus communication

I am trying to setup the master and slave for my ML1400 PLC using 2 core ( Tx-1 & Rx-1) RS 485 modbus communication. I received the data as my ML1400 channel 0 set as Modbus RTU master. I am trying to send my data with the same RS485 communication. How to setup the message instruction for that.

Hi Prasanna,
In Modbus RTU the master will initiate all communications. You state that "I received the data as my ML1400 channel 0 set as Modbus RTU master".
Without a MSG send command from the master to the slave, how are you receiving data back into the master?
Please check the setup of the ML1400.

https://rockwellautomation.custhelp.com/ci/fattach/get/26550/1242642753

Regards,

RS-485 always requires 3 conductors; Data +, Data - and Data Common.

If your other device doesn't have a dedicated Data Common terminal or pin, connect the Pin 2 "GND" on the MicroLogix 1400 Channel 0 port to the Chassis Ground for that device.

The MicroLogix 1400 RS-485 port is non-isolated and is not recommended for long distance communication.