Comtrol Modbus TCP Quick Start - Manual (Page 15)

Modbus/TCP Quick Start: 2000477 Rev. G Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters - 15
Configuring Modbus/RTU and Modbus/ASCII Slaves and Masters
5. Set up the Serial Configuration for your device.
6. Configure the serial port for Modbus/RTU-to-Master operation. Under General Protocol Settings:
a. Set Serial Port Protocol to Modbus/RTU-to-Master.
b. Enable Discard Rx Packets With Errors.
7. Scroll to the bottom of the page, verify that Reset Port and Save in Flash are selected, and click Submit.
Note: If necessary, see Filtering/Data Extraction Configuration on Page 61 or Application Socket
Configuration on Page 67 for additional configuration procedures.