Host Types And Settings - Omron NT31 Setup Manual

Connecting to the Host's RS-422A/485 Port
Note
Reference:
5-2-1

Host Types and Settings

This connection method can be used only with the NT link (1:N) meth-
od (standard or high-speed) of type RS-485.
PT
RS-485 cable
(max. 500 m)
• Method in which the RS-422A ports of multiple NT31/NT31Cs and the
RS-422A port of the host are connected in a 1:N connection (page 121).
This connection method is used with the RS-422A type NT link (1:N)
method (standard or high-speed).
PT
RS-422A cable
(max. total length 500 m)
• Method in which the RS-485 ports of multiple NT31/NT31Cs and the RS-
485 port of the host are connected in a 1:N connection (page 124).
This connection method is used with the RS-485 type NT link (1:N)
method (standard or high-speed).
PT
RS-485 cable
(max. total length 500 m)
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 communications failures.
(At termination)
PLC
Relay terminal block
Max. 2 m
NT31C NT31 NT31
NT31
(At
(Not at (Not at
termination) (Not at
termination)
termination)
termination)
Example of Good Connection
CS/CJ-series CPU Units cannot be connected with the 1:1 connection NT link
method. Use the 1:N connection NT link method (standard or high-speed) in-
stead to make the 1:1 connection. For details, refer to Using the NT link (1:N)
Method (page 109) 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.
Host
Host
Host
PLC
NT31 NT31C NT31 NT31
Examples of Bad Connections
Section 5-2
PLC
Relay terminal block
NT31C NT31
95