Host Types And Settings - Omron NT31 Setup Manual

Connecting to the Host's RS-422A/485 Port
PLC (At termination)
NT31C
(Not at (Not at
termination) (Not at
termination)
Example of Good Connection
Reference: CS-series CPUs cannot be connected with the 1:1 connection NT link method.

5-2-1 Host Types and Settings

When Using the Host Link Method
This connection method is used with the RS-485 type NT link (1:N) method
(standard or high-speed).
Note One end of the wire must always be connected to the host (PLC), and there must
be no branching. Branching will cause problems such as transmission delays
and communication failures.
Relay terminal block
Max. 2 m
NT31 NT31 NT31
NT31
(At
termination)
termination)
Use the 1:N connection NT link method (standard or high-speed) instead to
make the 1:1 connection. For details, refer to Using the NT link (1:N) Method
(page 111) or Using the High-speed NT link (1:N) Method (page 113).
The types of host that have an RS-422A port and can be connected to the
RS-422A/485 port of the NT31/NT31C, and the settings to be made at the host,
are described here.
Compatible Host Units
Some models and series of OMRON PLCs have the RS-422A/485 type host link
function built in. With the CS-series and CQM1H, the host link method can be
used by installing a serial communication board. In addition, some C200HX/HG/
HE(-Z)E devices have an integral CPU that can be connected in the host link
method by installing a communication board.
With the CPM2A and CPM2C, an RS-422A type of 1:1 NT Link can be created
through a CPM1-CIF11 RS-422A Adapter.
Check the model and series of the PLC and the type of the installed Board or Unit
before making a connection.
PT
RS-485 cable
(max. total length 500 m)
PLC
NT31C NT31 NT31 NT31C
Examples of Bad Connections
Section
Host
PLC
Relay terminal block
NT31
5-2
99