
2. TASK CONTROL FUNCTION
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PMC CONTROL SOFTWARE
80
(1) Priority
In the PMC control software, the execution priority of ladder
programs, PMC screen display, and C programs is as follows:
First-level ladder program > Second-level ladder program >
highest-priority C program > PMC screen display > C program tasks
In this manual, PMC screen display refers to displaying PMC
diagnostic screens and PMC built-in programmer function screens.
Priority
High
First–level ladder program
Second–level ladder program
Low
*a
C program tasks
(priority 10 to 99)
Task 1, third–level ladder program
Task 2
.
Task n
Highest–priority C program
PMC screen display
*b
*c
*d
(NOTE1)
(NOTE2)
(2) C program processing time
The processing time for a C program is determined according to the
LADDER EXEC ratio set on the system parameter screen of the PMC
programmer function.
For example, if LADDER EXEC is set to 100%, in each 8 ms cycle,
5 ms is allotted to the processing of the first-level and second-level
ladder programs (*a), and the remaining 3 ms is allotted to PMC
screen display and C program processing (*b to *d).
[Setting range of LADDER EXEC]
D 40% to 150% (2 ms to 7.5 ms) in the ladder division method
D 40% to 120% (2 ms to 6 ms) in the ladder non-division method
0 8 16 24 (ms)
*a
*b to *d
2.7
RELATIONSHIP
BETWEEN LADDER
PROGRAMS AND C
PROGRAMS
2.7.1
PMC-SC/SC3/SC4/NB/
NB2