Function Block - Off timer.


IN : BOOL  Timer command
PT : TIME  Programmed time

RST : BOOL Reset (TOFR only)


Q : BOOL   Timer elapsed output signal
ET : TIME  Elapsed time

Time diagram

TofDiag.gif (3189 octets)


The timer starts on a falling pulse of IN input. It stops when the elapsed time is equal to the programmed time. A rising pulse of IN input resets the timer to 0. The output signal is set to TRUE on when the IN input rises to TRUE, reset to FALSE when programmed time is elapsed..

TOFR is same as TOF but has an extra input for resetting the timer

In LD language, the input rung is the IN command. The output rung is Q the output signal.

ST Language

(* MyTimer is a declared instance of TOF function block *)
MyTimer (IN, PT);
Q := MyTimer.Q;
ET := MyTimer.ET;

FBD Language

TofFbd.gif (1250 octets)

LD Language

TofLd.gif (1352 octets)

IL Language:

(* MyTimer is a declared instance of TOF function block *)
Op1: CAL MyTimer (IN, PT)
     LD  MyTimer.Q
     ST  Q
     LD  MyTimer.ET
     ST  ET

See also