Watlow LogicPro - Manual (Page 140)

Chapter 10: Function Blocks LogicPro User’s Guide
124 Watlow Anafaze Doc.# 28002-00 Rev 3.00
PT is the timer on-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 on-delay output bit. This bit is enabled and
passes power when the elapsed time becomes equal to the
preset time, and remains enabled until the enable bit is False.
ET is the timer on-delay elapsed time. The value of this
Variable increments in thousandths of a second when
triggered by a True condition of the enable bit until the
elapsed time is equal to the preset time. The elapsed time
retains this value until the enable bit is False. If the enable bit
becomes False before the elapsed time equals the preset time,
the elapsed time resets to zero.
Figure 10.8 illustrates the relationship between the inputs and
outputs of the TON function block and shows how the INP
signal and ET (timer) determine the state of the output Q, INP
and Q signals are high or low. ET is an analog value on the
vertical axis. Time is on the horizontal axis.
Figure 10.8 Relationship Between Inputs and
Outputs of TON Function Block
Timer Off-Delay (TOF)
The Timer Off-Delay function block, shown in Figure 10.9 on
page 125, provides a time delay for disabling an event at a
preset time interval.
INP
ET
Q
Timer On Delay (TON) Timing