Mitsubishi Electric FR-F700PJ Instruction Manual page 225

Communication operation and setting
(3) Connection with RS-485 computer
Wiring of one RS-485 computer and one inverter
Computer side terminals *1
Receive data
Receive data
Send data
Send data
Signal ground
Wiring of one RS-485 computer and "n" (multiple) inverters
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 inverters 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 inverter remotest from the computer. (Terminating resistor: 100)
NOTE
 Do not use pins No. 2, 8 of the communication cable. (Refer to page 218)
 When making RS-485 communication among the FR-F700PJ, FR-E500, FR-S500, 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 inverter
malfunction or failure. (Refer to page 218)
(4) Two-wire type connection
If the computer is 2-wire type, a connection from the inverter can be changed to 2-wire type by passing wires across
reception terminals and transmission terminals of the PU connector pin.
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.
220
Cable connection and signal direction
Cable connection and signal direction
SG
Station 1
Inverter
Computer
Transmission enable
Reception enable
Communication cable
2
0.2mm or more
Communication cable
SG
Station 2
Inverter
Pass a wire
SG
Inverter
PU connector
SDA
SDB
RDA
RDB
SG
Terminating
resistor
SG
Station n
Inverter
Inverter
SDA
SDB
RDA
RDB
SG
*2