
Chapter 5. Application instructions
5-96
5.12.3 WDT, WDTP
WDT
(Watch dog timer
clear)
FUN(202) WDT
FUN(203) WDTP
Applicable
CPU
K200S
K300S
K1000S
Available Device
Flag
Instructions
M
P
K
L
F
T
C
S
D
#D Integer
Steps
Error
(F110)
Zero
(F111)
Carry
(F112)
WDT
WDTP
1
1) Functions
-
Resets the watch dog timer in a sequence program
-
Used when the period of scan time (from step 0 to END in the sequence program) exceeds the set
value of watch dog timer depending on conditions. If the scan time exceeds the set value of watch
dog timer at every scan, change the set value of watch dog timer by the parameter setting
-
Set the set value of the watch dog timer so that ‘t1’ from step 0 to WDT(P) instruction and ‘t2’ from
the WDT(P) to END instruction do not exceed the set value. (See the diagram below)
-
The WDT(P) instruction can be user two or more times during one scan. However, please be
careful when use WDT(P) instruction because if an error occurs, the outputs cannot be turned off
immediately.
-
Values of scan time stored in special resisters (F device) are not cleared though the WDT(P)
instruction is executed.
WDT
WDTP
t1
t2
WDTP
Step 0
END