Rising Edge Detection - JUMO LOGOSCREEN 601 Manual

9.5

Rising edge detection

This function module detects a rising edge (transition 0 -> 1) .
Call
R_TRIG<instance> (CLK);
Input
Parameter
<Instance>
CLK
Output
Parameter
Q
Comment
The operating principle of the function module corresponds to the following program code:
VAR CLK : BOOL; END_VAR
VAR Q : BOOL; END_VAR
VAR M : BOOL := FALSE; END_VAR
Q := CLK AND NOT M;
M := CLK;
The Q output remains at its Boolean value from one call until the next. It follows the transition of the input
signal (CLK) from "0" to "1" and returns to "0" the next time it is called.
Example
IF reset_flag THEN
bool_out01 := FALSE;
END_IF;
R_TRIG01 (bool_in01);
(* detection of a rising edge at input bool_in01 *)
bool_out01 := R_TRIG01.Q;
(* short pulse at output bool_out01 for rising edge at input *)
Data type Description
01 to xx (specify instance with two digits)
BOOL Due to a rising edge (0 -> 1) at CLK, Q = TRUE
Data type Query
BOOL OUT := R_TRIG<instance>.Q;
9 Function modules
57