YASKAWA E7U Programming Manual page 90

Communication Connection Terminal
Modbus communication uses the following terminals: S+, S-, R+, and R-. The terminating resistance must be turned ON only
if the Drive is at the very end of the Serial Communication chain. Set the terminating resistance by turning ON pin 1 of switch
S1 On the Drives terminal board. Switch S1 is located directly above the left most relay module.
RS-422A
or RS-485
Terminating resistance (1/2W, 110 Ohms)
IMPORTANT
Procedure for Setting Up Communication
Use the following procedure to perform communication with the PLC.
1. Turn OFF the input power to the Drive and connect the communication cable between the PLC and the Drive.
2. Turn ON the input power to the Drive.
3. Set the required communication parameters (H5-01 to H5-09) using the Digital Operator.
4. Turn OFF the input power to the Drive, and check that the Digital Operator display has completely faded.
5. Turn ON the input power to the Drive once again.
6. Perform communication with the PLC.
Switch
Fig. 63 Communication Connection Terminals and Terminating Resistance
1. Separate the communication cables from the main circuit cables and control circuit wiring.
2. Use shielded cables for the communication cable, and use proper shield clamps.
3. When using RS-485 2 Wire communication, connect S+ to R+, and S- to R-, on the control circuit termi-
nal board. See diagram below.
4. Terminate shield at one end only.
S1
O
1
1
F
F
2
Programming 84
Terminating
resistance on
DIP Switch S1 located on
terminal board.