182
Communication operation and setting
(3) Connection with RS-485 computer
Wiring of one RS-485 computer and one inverter
Wiring of one RS-485 computer and "n" (multiple) inverters
∗1 Make connection in accordance with the instruction manual of the computer to be used with.
Fully check the terminal numbers of the computer since they vary with the model.
∗2 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: 100Ω)
(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.
NOTE
Do not use pins No. 2, 8 of the 10BASE-T cable. (Refer to page 180)
When making RS-485 communication among the FR-D700 series, FR-E500 series and FR-S500 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 180)
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.
Computer side terminals *1
Send data
Send data
Receive data
Receive data
Signal ground
RDB
RDA
SDB
SDA
PU connector
SG
Inverter
0.2mm
2
or more
Cable connection and signal direction
10BASE-T cable
Computer *1
Station 1 Station 2
Inverter Inverter Inverter
Station n
Terminating
resistor
*2
Cable connection and signal direction
10 BASE-TCable
SG
SG
RDB
RDA
SDB
SDA
SG
RDB
RDA
SDB
SDA
SG
RDB
RDA
SDB
SDA
Send
Receive
SDA
SDB
RDA
RDB
SG
SG
InverterComputer
Pass a wire
Transmission enable
Reception enable