LTP

VAR_INPUT

VAR_INPUT
    IN : BOOL; (*Trigger for Start of the Signal*)
    PT : LTIME; (*The length of the High- Signal*)
END_VAR

VAR_OUTPUT

VAR_OUTPUT
    Q  : BOOL; (*The pulse*)
    ET : LTIME (*elapsed time since pulse start*)
END_VAR

If IN is FALSE, the outputs are FALSE or 0. As soon as IN becomes TRUE, Q also becomes TRUE and remains TRUE for the pulse duration PT. As long as Q is TRUE, the time is incremented in nanoseconds in ET, until the value reaches PT. The value then remains constant. The output Q remains TRUE until the pulse duration has elapsed, irrespective of the state of the input IN. Q therefore supplies a signal over the interval specified in PT.
Graph showing LTP over time:

Requirements