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LogicPro User’s Guide Chapter 10: Function Blocks

Doc.# 28002-00 Rev 3.00 Watlow Anafaze 125

The output bit (Q) is enabled upon a True condition of the

enable bit (INP). When there is a False condition of the enable

bit, TOF continues to enable the output bit while it increments

the integer elapsed time (ET) value in thousandths of a second

until the integer preset time (PT) value is reached. Once the

elapsed time value equals the preset time value, the output is

disabled. The elapsed time value resets and remains at zero as

long as the enable bit is False.

Figure 10.9 Timer Off-Delay Function Block

Inputs

INP is the Timer Off-Delay enable bit. A True condition of this

bit enables the output bit. A False condition of this bit triggers

the elapsed time to start incrementing in thousandths of a

second until the elapsed time equals the preset time. After this

delay, the output bit is disabled until the next True condition

of the enable bit. In a program using Ladder logic, the value

of INP is determined by the Boolean evaluation of elements

placed between the left power rail and INP in the function

block. In an FBD program, it is determined by the Variable

connected to INP. If no contacts are placed on the rung before

INP, the value of INP is always True.

PT is the Timer Off-Delay preset time. In Ladder logic, assign

this input a symbolic name or constant value in the Assign

Function Block Symbolic Input/Output dialog box. In

FBD, assign a variable to this input in the Variable

Assignment dialog box. The range of values this Variable

can assume is from 1 to 32,767 for INT type Variables and 1

to 2,147,483,647 for LONG type Variables thousandths of a

second. If this Variable is assigned a value out of these ranges,

unpredictable results will occur.

Outputs

Q is the timer off-delay output bit. This bit is enabled and

passes power when the enable bit is True. When the enable bit

is False, it remains enabled until the elapsed time becomes

equal to the preset time.

ET is the timer off-delay elapsed time. The value of this

Variable increments in thousandths of a second when

triggered by a False condition of the enable bit until the

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Watlow LogicPro Bedienungsanleitung Seite 141