Toshiba 6F3B0253 user manual Wdt, Watchdog timer reset

6F3B0253

7. Instructions

FUN 143

WDT

Watchdog timer reset

Expression

Input − [ WDT n ]− Output

Function

When the input is ON, this instruction extend the scan time over detection time by 200 ms. Normally, T1/T1S detects the scan time-over if a scan is not finished within 200 ms. This instruction can be used to extend the detection time.

Execution condition

Input		Operation	Output
OFF	No execution		OFF
ON	Execution		ON

Operand

Name

Device

Register

Constant

Index

X

Y

R

S

T.

C.

XW

YW

RW

SW

T

C

D

I

J

K

n

Extend time

1 - 100

Example

When R020 is ON, the scan time detection time is extended by 200 ms. The operand n has no effect on the extended time. It is fixed as 200 ms.

			Normal detection point			Extended point
0	50	100	150	200	250	300	(ms)

Extended by 200 ms

Scan

WDT instruction

execution

Note

•As for the upper T-series PLCs, the operand n specifies the extended time. However in the T1/T1S, it is fixed as 200 ms regardless of the operand n.

Basic Hardware and Function 211