Omron NT31 NT31C manual 115

Connecting to the Host’s RS-422A/485 Port Section 5-2

Setting the Front Switches

Port 1

RS-232C

Port 2 RS-422A/485

RDY

COMM1

COMM2

PORT1

OFF ON TERM

24 WIRE

PORT2

(RS422/

RS485)

SCB41

Terminal resistance setting switch (TER)

Set to ON (Terminal resistance is present.) (right side)

Two wire type/four wire type changeover switch (WIRE) For RS-422A : 4 (4 wire type) (right side)

For RS-485 : 2 (2 wire type) (left side)

Allocation DM Area Settings for CPU

Settings are written from the Programming Device (a Programming Console or CX-Programmer) directly into the allocation DM area (system setting area) of the CPU. After settings are written, they become effective by turning the power ON, restarting the unit, restarting the communication port, or executing the STUP command.

In the following, the channel numbers of the allocation DM area and settings are shown.

Allocation DM
area (CH)	Writing Value	Settings
Port 2
DM32010	8200	NT link (1:N) mode
DM32011	0000 to 0009 (*1)	Communications baud rate (standard)
DM32016	000j	j = The largest model number of the con-
		nected PT (0 – 7)

*1 Set any value between 0000 and 0009 Hex for the communications baud rate. The same baud rate will be used regardless of the value as long as it is between 0000 and 0009 Hex.

For example, when connecting PTs with model numbers 3, 4, 5, and 6 to port 2 in the NT link (1:N), set a value of 8200 Hex for D32010, 0000 Hex for DM32011, and 0006 Hex for D32016.

Using the High-speed NT Link (1:N) Method

Compatible Host Units

Only OMRON’s CS1H and CS1G PCs support the high-speed 1:N NT Link through RS-422A/RS-485. The high-speed 1:N NT Link must be established through a CS1W-SCB41-E Serial Communications Board. (If a Serial Commu- nications Board is used, even CS1-series Units without the “-V1” suffix can be connected via high-speed 1:N NT Link.)

Be sure to check the model number of the PC and Board/Unit before trying to establish the high-speed 1:N NT Link.

The following table shows which CS1-series PCs can be connected to an

NT31/NT31C with the high-speed 1:N NT Link through RS-422A/RS-485.

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