Omron CJ2 CPU UNIT SOFTWARE User Manual page 419

1
Synchronous Signal
When the power supply to the PLC is turned ON, the CPU Unit generates a synchronous signal
and then starts initializing the synchronous data. The CPU Units and Synchronous Units also
start internal processing at this time.
2
Synchronous Input Data Refresh (Synchronous Units to CPU Unit)
The Synchronous Units sent synchronous data to the CPU Unit.
3
Synchronous Interrupt Task
The CPU Unit executed the synchronous interrupt task. (Synchronous unit operation can be
used without using the synchronous interrupt task.)
4
Synchronous Processing Time
The synchronous processing time is the time required for one series of synchronous operation
processing in one synchronous operation cycle. It is the time from when the synchronous signal
is generated until execution of the synchronous interrupt task has been completed. After the syn-
chronous processing time, normal processing is performed until the synchronous control cycle
has expired.
The synchronous processing time must be less than the synchronous operation cycle. (The max-
imum and present values of the synchronous processing time can be monitored in the Synchro-
nous Operation Status Dialog Box of the CX-Programmer.)
5
Synchronous Operation Cycle
When the synchronous operation cycle time has expired, the synchronous signal is generated
again.
6
Synchronous Output Data Refresh (CPU Unit to Synchronous Units)
The CPU Unit sends synchronous data to the Synchronous Units.
7
The overall process is repeated from step 2.
Precautions for Correct Use Precautions for Correct Use
The CPU Unit interrupts normal processing during the synchronous input data refresh, synchro-
nous interrupt task execution, and synchronous output data refresh. The normal cycle time of the
CPU Unit will be extended by the time required for these processes. Be sure that the control sys-
tem will not be adversely affected if the cycle time is extended before using synchronous unit
operation.
CJ2 CPU Unit Software User's Manual
10 CPU Unit Functions
10-85
10