10-17
10 CPU Unit Functions
CJ2 CPU Unit Software User’s Manual
10-2 Cycle Time/High-speed
Processing
10
10-2-5 Background Execution
This example shows background execution when index register output is specified, as is possible for
MAX(182), MIN(183), and SRCH(181).
z Programming without Background Execution
As shown below, the PLC memory map address of the word containing the maximum or minimum
value is output to an index register.
z Programming with Background Execution
With background execution, the PLC memory map address of the word containing the maximum or
minimum value is output to A595 and A596. MOVL(498) is then used to move the PLC memory map
address to the index register.
Programming Example 2
MAX
D0
D100
D200
a
MOV
,IR0
D300
MAX(182) is executed completely as
soon as the execution condition "a" turns
ON, and the actual memory map address
of the word containing the maximum
value is output to IR0
The contents of the I/O memory word
indicated by the memory map
address in IR0 is copied to D300.
Execution condition
RSET
a
SET
b
MAX
D0
D100
D200
a A202.00
MOV
,IR0
D300
MOVL
A595
IR0
b A202.00
RSET
b
MAX(182) execution is started if execution
condition "a" is ON and the Communications
Port Enabled Flag is ON. The actual memory
map address of the word containing the
maximum value is output to A595 and A596.
Communications
Port Enabled
Flag
Execution
condition
Execution
condition
Communications
Port Enabled
Flag
Execution condition "b" is turned ON to
execute MOVL(498).
"a" is turned OFF so that MAX(182) will not
be executed in the next cycle.
When execution condition "b" is ON
and the Communications Port
Enabled Flag is ON, MOVL(498)
copies the actual memory map
address in A595 and A596 to IR0.
Extra
processing
required to
move
address.
The contents of the I/O memory word
indicated by the memory map
address in IR0 is copied to D300.
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