Omron NT631 Operation Manuals page 123

Connecting to the Host's RS-422A/485 Port
The host link method cannot be used when an NT631/NT631C is connected using
RS-485. To use the host link method, connect by RS-422A.
S Settings at the host
When using the RS-422A type host link method, the settings shown below must
be made at the host (depending on the unit, some of these settings may not be
necessary, or settings not shown here may be necessary).
Item
I/O port
Communications speed
Transfer code
Parity
1-to-1/1-to-N
Instruction level
Unit #
*1 Set the host link communications speed at 9600 bps or 19200 bps with the
"Comm. Speed" memory switch at the NT631/NT631C. For details, refer to
"Setting the Host Link Method" (page 173).
*2 The 1-to-N setting enables BCC (Block Check Character). It is not actually
possible to connect more than one NT631/NT631C in a single host link.
The setting methods for each type of unit are described in the following.
Setting at Host
RS-422A
Set the same speed as for the NT631/NT631C.
ASCII, 7 data bits, 2 stop bits
Even
(*2)
1-to-N
Level 1, 2, 3
00
Section 5-2
(*1)
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