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7. Modbus-TCP
Modbus-TCP is supported by relay module. Standard Modbus-TCP is implemented at port
number 502. The Modbus-TCP address table is as following:
Address
Ch
Function Code
Description
Access
00000
1
05
Relay 1 output control
Write/Read
00001
2
05
Relay 2 output control
Write/Read
To look into Modbus-TCP frame structure or create your own Modbus-TCP program, here are the
detailed message frame for each command:
To switch on relay channel 1 output
Ethernet frame: 0x05 0x00 0x00 0xFF 0x00
To switch off relay channel 1 output
Ethernet frame: 0x05 0x00 0x00 0x00 0x00
To switch on relay channel 2 output
Ethernet frame: 0x05 0x00 0x01 0xFF 0x00
To switch off relay channel 2 output
Ethernet frame: 0x05 0x00 0x01 0x00 0x00
