Mitsubishi Electric FR-D720-0.2K-G Instruction Manual page 186

(3) Connection with RS-485 computer
Wiring of one RS-485 computer and one drive unit
Computer side terminals *1
Receive data
Receive data
Send data
Send data
Signal ground
Wiring of one RS-485 computer and "n" (multiple) drive units
Computer *1
Receive
Send
SG
 Make connection in accordance with the Instruction Manual of the computer to be used with.
Fully check the terminal numbers of the computer since these vary with the model.
 The drive units may be affected by reflection depending on the transmission speed or transmission distance. If this reflection hinders
communication, provide a terminating resistor. If the PU connector is used to make a connection, use a distributor since a terminating
resistor cannot be fitted. Connect the terminating resistor to only the drive unit remotest from the computer. (Terminating resistor: 100)
NOTE
 Do not use pins No. 2, 8 of the communication cable. (Refer to page 181.)
 When making RS-485 communication among the FR-D700-G series, FR-E500 series, FR-S500 series and FR-F500J
series, incorrect connection of pins No.2 and 8 (parameter unit power supply) of the above PU connector may result
in the drive unit, inverter malfunction or failure. (Refer to page 181.)
(4) Two-wire type connection
If the computer is 2-wire type, a connection from the drive unit can be changed to 2-wire type by passing wires across
reception terminals and transmission terminals of the PU connector pin.
Transmission enable
REMARKS
 A program should be created so that transmission is disabled (receiving state) when the computer is not sending and reception
is disabled (sending state) during sending to prevent the computer from receiving its own data.
 The passed wiring length should be as short as possible.
Cable connection and signal direction
Cable connection and signal direction
Communication cable
SG
Station 1
Drive unit
Computer
Reception enable
Communication operation and setting
Communication cable
2
0.2mm or more
SG
Station 2
Drive unit
Drive unit
SDA
SDB
RDA
RDB
Pass a wire
SG
SG
Drive unit
PU connector
SDA
SDB
RDA
RDB
SG
Terminating
*2
resistor
SG
Station n
Drive unit
4
183