How do I configure the WR21 as a Modbus Gateway?

Configuration of the WR21 as a Modbus Gateway: I have a slave RS-232 device connected to the modem and a Modbus TCP master trying to poll the slave through the modem’s LAN port (and later over the cellular interface). What are the correct settings at the Modbus 0 and Modbus Slaves headings in the Legacy Protocols section of the modem configuration?

I have similar problem.
Is it now work to you?
If yes, can you write please what are the settings you set?

The following settings work well for me:

Interfaces: Serial: SerialPort 0:
Enable, set Baud Rate, Data Bits and Parity to match the connected serial device. Set Flow Control to NONE.

Legacy Protocols: MODBUS Gateway: MODBUS 0:
Enable, Async Port = 0, Async Mode = RS232, Duplex Mode = Half, Operation Mode = Act as Master, Idle Gap = 20 ms, Fix Slave Addr = 0, Adjust Slave Addr = 0

In the IP Port Table: Port 502, 1 Socket, TCP Mode

1 Like