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2.5 External terminal resistance
According to the site situation, the serial port side of gateway needs external 120 Ω
terminal resistance. The RS485 bus supports a maximum of 32 nodes without relay,
A "daisy chain" connection is used between nodes, and terminal resistors are required at
both ends of the communication cable, and their resistance is required to be approximately
equal to the characteristic impedance of the transmission cable. In short-distance
transmission, no terminating resistor is required, that is, no terminating resistor is generally
required below 300 meters.
The terminating resistor is connected to the two ends of the transmission cable. When
Parameter Name
Defaults
Ethernet
side
Protocol converter IP
192.168.1.254
Subnet mask
255.255.255.0
LAN gateway IP
192.168.1.1
Modbus TCP data port
502
Configure the por
1024
Modbus-TCP watchdog time
30S
The enabling of Modbus-TCP
watch dog
enable
Gateway work mode
Transmission Mode
Gateway station Number
247
Serial
side
Serial port mode
Master station mode
Protocol type of Modbus
Modbus RTU
Serial port baud rate
9600bps
Check digit
No check
Data bits
8bit
Stop bit
1bit
Receive character interval
3.5t
Message sent
0
Timeout processing
Data retention
Slave response timeout
500ms