TP (Functionblock)

The TP function block is a pulse timer that enables "q" (the output) for a preset amount of time.

When trig is set TRUE, the "q" output is set TRUE and the elapsed time counter (et) is reset to zero and incremented until the preset timer value is reached, after which the "q" output is set FALSE.

Only during this period of time is "q" set to TRUE.

Once the timer is running, any changes to the trig input are ignored until after the preset value is reached.

This image shows the TP function block timing:

Input:

trig : BOOL (true/false)

On the leading edge of this input, the timer will start and set the "q" output true for the specified "pt" time

pt : DINT (0..2147483648)

Specifies how long the "q" output should be true - specified in ms.

Output:

et : DINT (0..2147483648)

The current value of the timer.

q : BOOL (true/false)

Output from the timer. This will go high until "et" equals "pt"

Declaration:

FUNCTION_BLOCK TP;
VAR_INPUT
  trig : BOOL; | Leading edge on this signal will start the timer
  pt   : DINT; | Time where 'q' will be high after 'trig' signal
END_VAR;
VAR_OUTPUT
  q   : BOOL; | Output from timer
  et   : DINT; | Current timer value          
END_VAR;

Example:

INCLUDE rtcu.inc
 
VAR_INPUT
  input1 : BOOL; | Input that will enable the timer
END_VAR;
 
VAR_OUTPUT
  signal : BOOL; | Output that will follow the q output from the timer.
END_VAR;
 
VAR
  timer : TP; // Declare an instance of the TP functionblock
END_VAR;
 
PROGRAM test;
 
BEGIN
  timer();
  ...
  timer.pt := 100; // number of milliseconds the q output should be high
  timer.trig := input1; // The timer will start on a leading edge on input1
  signal := timer.q; // output will follow the q output from the timer
  ...
END;
END_PROGRAM;