3
SEQUENCE PROGRAM CONFIGURATION AND
EXECUTION CONDITIONS
3.3 Settings for Creation and Execution of Multiple Sequence Programs
3.3.3 Low speed execution type program
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(e) Low speed scan time
Low speed scan time is the sum of the execution time of all low speed execution
type programs and the low speed END processing time.
Refer to Figure 3.30 for differences between the low speed scan time and the
scan time.
1) Low speed scan time storage location
The CPU module measures the low speed scan time and stores it into the
special registers (SD528 to 535).
The low speed scan time can be checked by monitoring SD528 to 535.
Example: When SD528 is 50 and SD529 is 400, the low speed scan time is
50.4ms.
Remark
The low speed scan time and program processing time can be checked on the
screen displayed by selecting [Online] [Monitor] [Program monitor list] in GX
Developer.(
2) Accuracy and measurement of low speed scan time
The accuracy of each scan time stored into the special register is 0.1ms.
Even if the watchdog timer reset instruction (WDT) is executed in a sequence
program, the measurement of each scan time is continued.
3) When interrupt program/fixed scan execution type program is executed
The execution time of the interrupt program/fixed scan execution type program
is added to the low speed scan time.
(f) Low speed execution watch time
The low speed execution watch time is measured by the timer that watches the
low speed scan time.
The setting range is 10 to 2000ms (setting unit: 10ms).
No default time is preset to the low speed execution watch time (There is no
default value.).
1) When low speed execution watch time is exceeded
A "PRG. TIME OVER (error code: 5010)" occurs when the low speed scan
time exceeds the preset low speed execution watch time.
Figure 3.35 Low speed scan time storage location
SD528
SD532
SD534
SD529
SD533
SD535
Present value
Minimum value
Maximum value
Stores low speed scan time of 1ms or less (unit s).
Stores low speed scan timein 1ms units.