A function block groups an algorithm and a set of private data. It has inputs and outputs. - Off timer.
Inputs
IN : BOOL Timer command
PT : TIME Programmed time
RST : BOOL Reset (TOFR only)
Outputs
Q : BOOL Timer elapsed output signal
ET : TIME Elapsed time
Time diagram
Remarks
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 FFLD 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
FFLD Language
IL Language:
(* MyTimer is a declared instance of TOF function block *)
Op1: CAL MyTimer (IN, PT)
FFLD MyTimer.Q
ST Q
FFLD MyTimer.ET
ST ET
See also
