Omron CJ2M-CPU34 - Page 53

9
．
Program
50
9.1.1. Outline of Processing
The following figure shows the data flow from when PLC (SCU) issues command data to
Destination Device using serial communications until PLC receives response data from
Destination Device.
(1)The ladder program specifies the communications sequence No. 900 and executes the
PMCR instruction.
(2) The PLC receives the response data from Sensor Controller according to receive
messages defined by the communications sequence No. 900 and stores them in the
response data storage area.
(3)The Sensor Controller executes the command by receiving the command data from PLC,
and returns response data to PLC.
(4)The PLC receives the response data from Sensor Controller according to the receive
messages defined by the communications sequence No. 900, and stores them in the
response data storage area.
PLC
RS-232C Sensor Controller
CPU Unit
SCU
Ladder program
Protocol macro data
Response data
(2) Sends the command
data.
(Sequence No. 900)
5501 onwards
Response data
storage area
(4) Receives the
response data and
stores them in the
specified memory.
(Sequence No. 900)
Command data
(1) Executes the PMCR
instruction.
(Specifying the sequence No.
900)
(3) Executes the
command and
returns the
response data.
PMCR
Sequence No. 1
Sequence No. 2
Sequence No. 900
：
5020 onwards
Send data
setting area