OSF (one shot falling)

The OSF instruction detects a falling edge of a Boolean variable. The OSF block sets output Q for one cycle when input CLK toggles from set to cleared (that is, a falling edge is detected at input CLK).
Languages supported: Function block diagram, ladder diagram, structured text.
This instruction applies to the Micro810, L20E, L50E, and L70E controllers.
OSF
OSF
OSF parameters
Parameter
Parameter Type
Data Type
Description
CLK
Input
BOOL
Checks the input for a falling edge. Any Boolean variable.
  • TRUE: No falling edge detected.
  • FALSE: Falling edge detected on input CLK, set output Q to TRUE.
Q
Output
BOOL
Indicates status for Q output.
  • TRUE: Falling edge detected, sets output Q for one more cycle.
  • FALSE: No change to output Q.

OSF examples

OSF function block diagram example
OSF function block diagram example
OSF ladder diagram example
OSF ladder diagram example
OSF structured text example
OSF structured text example
(* ST Equivalence: OSF1 is an instance of a OSF block *)
OSF1(cmd);
nb_edge := ANY_TO_DINT(OSF1.Q) + nb_edge;
Results
Results
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