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Chapter 6
MODBUS Communication
6.1 RS-485 Communication Wiring
ProNet series servodrives provide the MODBUS communication function with RS-485 interface,
which can be used to easily set parameters or to perform monitoring operations and so on.
The definitions of the servodrive communication connector terminals are as follows.
CN3
：
CN4
：
Note
：
1. The length of the cable should be less than 100 meters in a less disturbed environment. However, if
transmission speed is above 9600bps, please use the communication cable within 15 meters to ensure
the accuracy of transmission.
2. A maximum of 31 servodrives can be connected when RS485 is used. Terminating resistances are
used at both ends of the 485 network. If more devices are wanted to connect, use the repeaters
to expand.
3. CN3 of servodrive is always used as communication cable input terminal
，
and CN4 is always used as
communication cable output terminal(If still need to connect slave stations
，
the communication cable is
connected from CN4 terminal to the next slave station; if need not, add balance resistor in CN4
terminal).It is prohibited to connect CN3 of any two servodrives directly when multiple ProNet series
Terminal
Terminal
Terminal
Terminal No.
No.
No.
No.
Name
Name
Name
Name
Function
Function
Function
Function
1
5V
Power supply 5VDC.
2
5V
3
485+
RS-485 communication terminal
4
DGND
Ground
5
DGND
6
485-
RS-485 communication terminal
7
CANH
CAN communication terminal
8
CANL
CAN communication terminal
Terminal
Terminal
Terminal
Terminal No.
No.
No.
No.
Name
Name
Name
Name
Function
Function
Function
Function
1
—
Reserved
2
—
Reserved
3
485+
RS-485 communication terminal
4
DGND
Ground
5
DGND
6
485-
RS-485 communication terminal
7
CANH
CAN communication terminal
8
CANL
CAN communication terminal
