Omron Programmable Terminals NT631C - Manual (Page 279)

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Using an RS-232C/RS-422A Adapter Appendix C
When using the host link or NT link (1:1), set the RS-422A send mode to continual sending (set both SW1-5
and 6 OFF).
When using the NT link (1:N), set the RS-422A send mode to complies with CS control of RS-232C (i.e., one of
SW1-5 and SW1-6 must be ON).
Note (1) Do not set both SW1-5 and SW1-6 ON at the same time. This may damage internal circuits.
(2) The power supply to the device supplying +5 V must be turned OFF before starting wiring work.
(3) Before connecting the RS-232C cable and turning on the power to an RS-232C device such as a
PT (i.e., turning on the power to the Adapter), check that the cable is wired correctly and that the
DIP switch settings are correct. If the power is turned on while there is a wiring fault, the internal
circuits of the Adapter or the RS-232C device may be damaged.
(4) When the Adapter is connected to an OMRON C200HX/HG/HE(-Z)E, CQM1H, or CS/CJ-series
PLC as an RS-422A device, set DIP switches SW1-5 and SW1-6 as indicated below.
1 2 3 4 5 6
OFF
ON
SW1-3 SW1-4
ON
om on NT-AL001-E
(Factory settings)
[SW1-1] Not used (always ON)
[SW1-2] Setting for built-in terminal resistance
- OFF Terminator not set
- ON
Terminator set
[SW1-3, 4] Selection of 2-wire type/4-wire type
2-wire type (RS-485)
SW1-3 SW1-4
OFF
ON
4-wire type (RS-422A)
SW1-5 SW1-6
SW1-5 SW1-6
SW1-5 SW1-6
[SW1-5, 6] Selection of the RS-422A send mode
Continual sending
Complies with CS control of RS-232C
(Data sent at CS H)
Complies with CS control of RS-232C
(Data sent at CS L)
OFF
ON
OFF
ON
OFF
ON
5 6
SW1-5
OFF
SW1-6
ON