Omron NT31C Reference Manual page 372

Outline of Communications
4-2 Outline of Communications
4-2-1 Communication Protocol
1, 2, 3...
362
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.
Communication between the host and the PT takes place in accordance with the
following protocol.
1. In order to perform communications, it is necessary to open the communica-
tion line. Opening here means making the line usable.
2. In accordance with the commands, the PT is controlled or notification is re-
ceived from the PT.
3. To terminate communication, close the communication line.
[Host program]
Line opened
OPEN instruction
Command
:
transmission
PRINT #instruction
:
:
:
LINE INPUT
#instruction
:
CLOSE instruction
Line closed
Once the line has been opened, it can be used until it is closed.
Function of Each Instruction
OPEN instruction:
PRINT #instruction:
LINE INPUT #instruction: Receives the command or response from the PT.
CLOSE instruction:
For detailed information on instructions, refer to the BASIC language instruction
manual for the host.
Operation When Using Instructions
The flow of communications between the host and the PT follows one of the
three patterns indicated below, depending on the types of command and the set-
tings made for response with the memory switches. Refer to section 6 of the Set-
up Manual for details.
• Pattern with write command when No is set for the response
[Operation at host]
Command transmission
However, when an error occurs, an error response is returned.
• Pattern with data read command, re-send command, and data write command
when response Yes is set.
[Operation at host]
Command transmission
Command/response
reception
Communication line
Command/
response
transmission
Opens the RS-232C line.
Also sets the communication conditions at the host
side. Refer to the Setup Manual for details.
Sends commands to the PT via an RS-232C line.
In order to receive input delimited by commas and
double quotation marks, use LINE INPUT.
Closes the RS-232C line.
Data write command
Data write command
Response or re-send command
Section 4-2
[Operation at PT]
Command
reception
Command/
response
transmission
[Operation at PT]
Command processing
[Operation at PT]
Command reception
Command processing
Response transmission