Rs-232C Communications; Communications Procedure - Omron NT20S-ST121B-EV3 User Manual

RS-232C Communications

6-2

RS-232C Communications

Communications
6-2-1
1,2,3...
Host program
OPEN command
PRINT # command
LINE INPUT # command
CLOSE command
Operation by Operating
Commands
Message from Host to
NT20
Enquiry from Host to NT20
This section describes the communications procedure when using the NT20-
ST128 (RS-232C), and program flow using examples in BASIC.
Procedure
The Host and NT20 communicate according to the following procedure.
1. The RS-232C circuit must be opened (i.e., communications enabled) be-
fore communications can start.
2. Commands are used to control the PT and to receive notification from the
NT20.
3. Close the RS-232C circuit again after communications have been complet-
ed.
Open circuit
Send instruction
Close circuit
After a circuit has been opened, it can be used until it is closed again.
OPEN: Opens the RS-232C circuit. The Host communications condi-
tions are also set.
Refer to 3-5-7 Setting RS–232C Communications Conditions
(NT20-ST128) on page 99.
PRINT#: Sends an instruction via the RS-232C circuit to the NT20.
LINE INPUT#: Receives a command from the NT20. [LINE INPUT] is used
when receiving input delimited by commas (,) or double quo-
tation marks (").
CLOSE: Closes the RS-232C circuit.
Refer to the Host's BASIC Manual for more details about the
commands.
The operating commands display monitored data from the production line and
messages to the factory workers. They are also used for NT20 control and
management.
The communications flow between the Host and NT20 differs according to the
following three cases:
Host program
Message operating command
Message to PT
Host program
Enquiry operating command
Enquiry
Receive command
RS-232C circuit
Open
status
Send instruction
Response operating command
Section 6-2
NT20 operation
Receive instruction
Send instruction
NT20 operation
Process message
NT20 operation
Receive command
Send response command
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