CODESYS problems with edge detection (bounce)

Question

I have a problem with my CODESYS program. I have three buttons, which are defined as input. For each button a number is stored. For example the number 1. I have now created a program, which recognizes an edge on the button and stores the numerical value (2) of the button in an array. If you now press another button with the value (3), the value is also stored in a variable again. The two variables should be added together. 2 + 3 = 23. In my program I have the problem that if I press the button tester with the value 2, I get 22. This is wrong. I think the problem is due to the bruise of the push button. Several edges are detected. So I wanted to solve this software technically with a delay. Do you have any idea how I could program that?

CODE:

IF (PLC_PRG.calls[5].gpio = TRUE) THEN // edge detection on gpio
    IF (counter = 0) THEN // counter for the first value
        floorstorage2[0] := PLC_PRG.calls[5].message.floorstore[5]; // save button value in the array to calculate the total
        counter := 1;
    ELSE
        floorstorage2[1] := PLC_PRG.calls[5].message.floorstore[5]; // save button value in the array to calculate the total
        counter := 0;
    END_IF
END_IF

IF (PLC_PRG.calls[6].gpio = TRUE) THEN // edge detection on gpio
    IF (counter = 0) THEN // counter for the first value
        floorstorage2[0] := PLC_PRG.calls[6].message.floorstore[6]; // save button value in the array to calculate the total
        counter := 1;
    ELSE
        floorstorage2[1] := PLC_PRG.calls[6].message.floorstore[6]; // save button value in the array to calculate the total
        counter := 0;
    END_IF
END_IF

IF (PLC_PRG.calls[7].gpio = TRUE) THEN // edge detection on gpio
    IF (counter = 0) THEN // counter for the first value
        floorstorage2[0] := PLC_PRG.calls[7].message.floorstore[7]; // save button value in the array to calculate the total
        counter := 1;
    ELSE
        floorstorage2[1] := PLC_PRG.calls[7].message.floorstore[7]; // save button value in the array to calculate the total
        counter := 0;
    END_IF
END_IF


GlobalVar.floorstorage := concat(floorstorage2[0],floorstorage2[1]); // Total of value 1 and value 2 (1 + 2 = 12)

Answer 1

You need to implement edge detection. Here is a code template you can use:

//  Generate Oneshot Signal 

VAR_INPUT
    SIGNAL : BOOL; // Input
END_VAR

VAR
    LATCH_SIGNAL : BOOL; // Latch
END_VAR

VAR_TEMP
    OS_P_SIGNAL : BOOL; // Oneshot - Rising edge detection
    OS_N_SIGNAL : BOOL; // Oneshot - Falling edge detection
END_VAR

//Code - Rising edge detection
OS_P_SIGNAL := SIGNAL AND NOT LATCH_SIGNAL;
LATCH_SIGNAL := SIGNAL;

//Code - Falling edge detection
OS_N_SIGNAL := NOT SIGNAL AND NOT LATCH_SIGNAL;
LATCH_SIGNAL := NOT SIGNAL;