Omron CJ2 CPU UNIT SOFTWARE User Manual page 346

10 CPU Unit Functions
Procedure
1
To enable background execution for the required instructions, make the background execution
settings on the Settings Tab Page in the PLC Settings Dialog Box from the CX-Programmer.
2
Set the logical port number to be used for background execution in the PLC Setup. This port
number will be used for all instructions processed in the background.
One port is used for all background execution. Background execution for an instruction can thus
not be started if background execution is already being performed for another instruction. Use
the Communications Port Enabled Flag to control instructions specified for background execution
so that no more than one instruction is executed at the same time.
3
If an instruction for which background execution has been specified is executed, execution will
only be started in the cycle in which the execution condition was met and execution will not be
completed in the same cycle.
4
When background execution is started, the Communications Port Enabled Flag for that port will
be turned OFF.
5
Background execution will be continued over several cycles.
6
When processing has been completed, the Communications Port Enabled Flag for that port will
be turned ON. This will enable another instruction to be executed in the background.
10-12 CJ2 CPU Unit Software User's Manual