User's Manual

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connect RS485 bus, the bus is generally connected with serial I/O board or Modbus I/O board.
Figure 4-2 RS485 LAN Structure
Engineering station
Controller and I/O
Explosion-proof wirelessHART
smart gateway
Control network
4.3 Modbus
The gateway supports RS485 serial port s Modbus RTU and Modbus TCP based on Ethernet. As a
sub-device of Modbus network, polling by Modbus master device or client end (PC system) is
requested.
4.3.1 Communication Setting
The communication setting in gateway shall set as the same as that of Modbus master device or
client end. Choose Setup > Protocol in the gateway webpage, to enter Protocol Setting.
Figure 4-3 Protocol Setting
Address: The address is used by gateway for ModbusRTU communication, range 1~247.
Baud Rate: Serial ModbusRTU communication date ratio or speed, 1200~ 115200 bits/s supported.
Parity: The setting determination is used for failure check s odd-even check of ModbusRTU