Omron SYSDRIVE 3G3RV, User Manual

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6
-78
n
Communications Specifications
The
RS-422A/485 communications specifications are shown in the following table.
n
Communications Connection Terminal
RS-422A/485
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.
Fig 6.55 Communications Connection Terminal
Item Specifications
Interface RS-422,
RS-485
Communications
Cycle
Asynchronous
(Start-stop synchronization)
Communications
Parameters
Baud
rate:
Select
from 1,200, 2,400, 4,800, 9,600, and 19,200 bps.
Data
length:
8
bits fixed
Parity: Select
from even, odd, or none.
Stop
bits:
1
bit fixed
Communications
Protocol
MODBUS
Number
of Connectable Units
32
units max. (when using RS-485)
IMPORTANT
1. Separate the communications cables from the main circuit cables and other wiring and power cables.
2. Use shielded cables for the communications 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.
RS-422A
or RS-485
R+
R-
Switch
1
Terminating resistance (1/2 W, 110 Ohms)
S+
S-
+
-
S1
O
F
F
1
2
Terminating
resistance
OFF ON
R+ R S+ S