Omron NT620C, Руководство по эксплуатации

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6-2 Section Outline of Communications
246
Notify commands
These commands serve to notify the host of the results of operation at the
NT620S/NT620C. Only these commands are issued by the NT620S/NT620C
and, therefore, there is no response for them.
The following four switches are available.
S
Touch switch input notify command Page 259
S
Numerical input notify command Page 260
S
Character string input notify command Page 261
S
PT status notify command Page 262
Re-send command
This command lets the NT620S/NT620C re-send a notify command. It is issued
from the host and the notify command issued last is re-sent from the NT620S/
NT620C.
S
Re-send request command Page 264
6-2 Outline of Communications
This section describes the basic communication protocol when using memory
link and the program flow for using memory link, taking RS-232C communica-
tions using the BASIC language as an example.
6-2-1 Communication Protocol
Communication between the host and the NT620S/NT620C takes place in ac-
cordance with the following protocol.
(1) In order to perform communications, it is first necessary to open the commu-
nication line. “Opening” here means making the line usable.
(2) In accordance with the commands, the NT620S/NT620C is controlled or no-
tification is received from the NT620S/NT620C.
(3) To terminate communication, the communication line is closed.
[Host program]
OPEN instruction
PRINT # instruction
CLOSE command
Communication line
Line opened
Command
transmission
Line closed
Command/response
transmission
Command reception
Command/
response
transmission
[Operation at NT620S/NT620C]
LINE INPUT # instruction
Open state
Once the line has been opened, it can be used until it is closed.
Function of each instruction
OPEN instruction : Opens the RS-232C line.
Also sets the communication conditions at the host
side (see page 54).
PRINT # instruction : Sends commands to the NT620S/NT620C via an
RS-232C line.