Omron CJ - 09-2009 Operation Manual page 165

Expanded System Configuration
NT Link System
(1:N Mode)
CPU
RS-232C
RXD
TXD
Note 1. Set pin 5 of the DIP switch on the front panel of the CPU Unit to OFF, and
set the serial communications mode in the PLC Setup to no-protocol com-
munications.
2. No-protocol communications are supported for Serial Communications
Units with unit version 1.2 or later only.
If the PLC and Programmable Terminal (PT) are connected together using
RS-232C ports, the allocations for the PT's status control area, status notify
area, objects such as touch switches, indicators, and memory maps can be
allocated in the I/O memory of the PLC. The NT Link System allows the PT to
be controlled by the PLC, and the PT can periodically read data from the sta-
tus control area of the PLC, and perform necessary operations if there are any
changes in the area. The PT can communicate with the PLC by writing data to
the status notify area of the PLC from the PT. The NT Link system allows the
PT status to be controlled and monitored without using PLC ladder programs.
The ratio of PLCs to PTs is 1: n (n ≥ 1).
Set the PT communications settings for a 1:N NT Link. Either one or up to
eight PTs can be connected to each PLC.
Applicable port
SCU
Peripheral port
RXDU
TXDU
General-purpose
external device
General-purpose
external device
Section 2-5
Serial
Communi-
CPU Unit
cations
Unit
RS-232C port
Yes
No Yes
(See note 1.) (See note 2.)
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