About Explicit Message Instructions - Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual

Network Instructions
Cycle time (First cycle)
Program execution
END(001) executed.
1. SEND(090),
RECV(098), or
CMND(490) I/O refreshing
executed.
Sends command.
2. Communications processing
during "serial communications
port servicing" (Composes and
sends FINS command.)

3-25-2 About Explicit Message Instructions

Methods for Using Explicit
Message Communications
1040
Note When SEND(090) is being executed, the contents of S and D are
read and a FINS command for data transmission is composed.
When RECV(098) is being executed, the content of S is read and a
FINS command for data reception is composed.
When CMND(490) is being executed, the content of S is read and the
corresponding FINS command is composed.
3. If the send processing cannot be completed in a the time available in "serial
communications port servicing" period, the processing will be continued in
the next cycle's serial communications port servicing.
4. When a response is returned, the system performs the following process-
es:
• Refreshes the destination words specified in the Network instruction
with the response data.
• Turns ON the port's Communications Port Enabled Flag.
• Refreshes the port's Communications Port Error Flag (A21900 to
A21907) and Communications Port Completion Code (A203 to A210).
3. Processing is
divided up over
several cycles.
Program execution
Peripheral
servicing
There are two methods that can be used to send explicit messages from a
PLC.
• Use the CMND(490) to send a FINS command code of 2801 hex
(EXPLICIT MESSAGE SEND).
• Use the following Explicit Message Instructions. (See note.)
Note These instructions are supported only by CS/CJ-series CPU Unit
Ver. 2.0 or later.
Cycle time (Second cycle)
END(001) executed.
I/O refreshing
4. Communications processing
during "serial communications
port servicing" (Receives
response.)
Section 3-25
Peripheral
servicing
Receives
response.