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3.2 Settings for Execution of Only One Sequence Program
3
SEQUENCE PROGRAM CONFIGURATION AND
EXECUTION CONDITIONS
(c) Scan time watch
The CPU module has scan time watch timers (watchdog timers).(
(2) in this
section)
(2) WDT (Watchdog timer)
The watchdog timer (hereafter abbreviated to the WDT) watches the scan time.
The default value is 200ms.
(a) WDT error
A WDT error is 10ms.
When the WDT (t) is set to 10ms, a "WDT ERROR" occurs within a scan time
range of 10ms<t<20ms.
(b) WDT Setting
The WDT setting can be changed within a range of 10ms to 2000ms in the PLC
RAS of the PLC parameter dialog box. (Setting unit: 10ms)
Remark
The execution time of the program being executed can be checked in the program
list monitor of GX Developer.(
(3) Function that repeats program at fixed intervals
The constant scan function(
Section 6.2)allows a program to be executed
repeatedly at fixed intervals.
When the constant scan is set, a program is executed at intervals of the preset
constant scan time.
Figure 3.19 PLC RAS (WDT Setting)