Omron CJ2 - 02-2010 User Manual page 241

Sharing Index Registers
The following setting can be made from the PLC Properties Dialog Box in the CX-Programmer to
control sharing index and data registers between tasks.
To share index registers between all tasks, clear the selection of the Use IR/DRs independently per
task Check Box in the PLC Properties Dialog Box.
Additional Information
The contents of an index register used inside a function block may be corrupted when the func-
tion block is called. Always save the contents of the index register before calling the function
block and then restore the contents after leaving the function block. Set the required contents in
the index register inside the function block.
Instructions using the index
register
Instructions using the index
register
CJ2 CPU Unit Software User's Manual
Function
block
6 I/O Memory Areas
Save
P_On
[MOVL IR0 Temporary internal address]
Set the required contents in the
index register inside the function
block definition.
Restore
P_On
[MOVL Temporary internal address IR0]
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