Omron NT31

16
Communications with the Host Section 1-4
Reflection-suppressing protective sheet NT30-KBA04
Chemical-resistant cover NT30-KBA01
Replacement battery 3G2A9-BAT08
1-3-2 Connecting to the Host
The NT31/NT31C has the following two communications ports.
•Serial port A:
• D-SUB 9-pin connector
• For RS-232C use only (The Support Tool and bar code readers can be
connected here.)
•Serial port B:
• D-SUB 25-pin connector
• For RS-232C or RS-422A/485 (Selectable by memory switch)
• (The Support Tool and bar code readers cannot be connected here.)
The host can be connected at either of these two ports.
The connection methods for each communications method at the PT and host
sides are indicated below. Make the settings in accordance with the communi-
cations method that can be used with the PLC to be connected and the condi-
tions at the operation site.
Reference: When using an RS-232C/422A Adapter (NT-AL001) with the host link or NT link
(1:1) communications method, RS-485 cannot be used. The connection must
be made with RS-232C or RS-422A.
1-4 Communications with the Host
The NT31/NT31C is connected to the host by one of the following communi-
cations methods.
The following communications can be used to connect an OMRON PLC:
•Host link
• 1:1 NT Link
• 1:N NT Link (standard or high-speed)
The following communications can be used to connect another companies’
PLC or FA computer:
• Communications protocol supported by the other company’s PLC
• Memory link
In all of these communications methods that can be used with NT31/NT31C,
data communications with host are by direct connection (Memory link is, how-
ever, a quasi-direct connection).
In the following, the host link and NT link that carry out the direct connection
will be discussed. Memory links will be explained in 1-5 Communications
Using Memory Links.
1-4-1 Direct Connection Function
With the NT31/NT31C, the bits and words referring to data required for dis-
play, and those for storing input data, can be allocated to any part of the PLC
memory area.