YASKAWA Varispeed G7 Series Instruction Manual page 327

Communications Connection Terminal
MEMOBUS communications use the following terminals: S+, S-, R+, and R-. Set the terminating resistance
by turning ON pin 1 of switch S1 for the last Inverter only, as seen from the PLC.
RS-422A
or RS-485
IMPORTANT
Procedure for Communicating with the PLC
Use the following procedure to perform communications with the PLC.
1. Turn OFF the power supply turned and connect the communication cable between the PLC and the
Inverter.
2. Turn ON the power supply.
3. Set the required communications constants (H5-01 to H5-07) using the Digital Operator.
4. Turn OFF the power supply, and check that the Digital Operator display has completely disappeared.
5. Turn ON the power supply once again.
6. Perform communications with the PLC.
INFO
-94
6
S+
+
-
S-
R+
Switch
R-
1
Terminating resistance (1/2 W, 120 Ohms)
Fig 6.60 Communications Connection Terminal
1. Separate the communication cables from the main circuit cables and other wiring and power cables.
2. Use shielded cables for the communication cables, connect the shield cover to the Inverter earth terminal,
and arrange the terminals so that the other end is not connected to prevent operating errors due to noise.
3. When using RS-485 communications, connect S+ to R+, and S- to R-, on the Inverter exterior.
R+
Set the timer on the master to monitor response time from the slave. Set the master so that if the slave does
not respond to the master within the set time, the same command message will be sent from the master
again.
S1
O
1
F
2
F
R S+ S
Terminating
OFF ON
resistance