12.
12 - 7
OVERVIEW OF PROCESSING PERFORMED BY THE QnACPU
12.1.2 Scan execution type program
(1) Definition
(a) The scan execution type program is a program that is executed once for every
scan, starting from the next scan after execution of the initial execution type
program.
(b) The execution type is set to "Scan" in program setting in the parameter mode of
GPP function.
(2) Execution of multiple scan execution type programs
If there are more than one scan execution type program, they are executed in
ascending order of the program numbers set in the parameter mode.
(3) END processing
When all the scan execution type programs have been executed, END processing is
performed and then the first scan execution type program is executed again.
By inserting a COM instruction at the end of a scan execution type program, END
processing (general data processing, link refresh) can be executed for each program.
(4) When constant scan time is set
*1
When constant scan is set, the scan execution type program is executed once for
every preset constant scan time.
REMARK
*1 Constant scan is a function whereby a scan execution type program is
repeatedly executed at fixed intervals.
See Section 10.2.
POINT
(1) For the index register processing in the case where an interrupt program is
executed during execution of a scan execution type program, refer to the
QnACPU Programming Manual (Fundamentals).
END
0
END
0
END
0
END
0
END
0
END
0
END
0
0
END processing
Initial execution type programs
STOP RUN
Power ON/RESET RUN
Scan execution type program A
Scan execution type program B
Scan execution type program C
1st scan
2nd scan
3rd scan
4th scan
Scan time