Defining Arrays.

2020-02-27T13:52:58.468000Z

Originally created by: scott_cunningham

A suggestion if your array is rather large: Use a method to check for all false and use AND_THEN, which is a conditional and check - if the first element is false, the rest of the IF is not evaluated... Something like this:

PROGRAM PLC_PRG
VAR CONSTANT
   c_min : INT := 0;
   c_max : INT := 5;
END_VAR
VAR      
   myArray : ARRAY[c_min..c_max] OF BOOL := [FALSE,FALSE,FALSE,FALSE,FALSE];
   DidIt : BOOL := FALSE;
END_VAR
IF NOT(DidIt) AND_THEN AllAreFalse() THEN
   DoSomething();
   DidIt := TRUE;
ELSE
   ; //not doing it anymore
END_IF

Once "DidIt" is TRUE, AllAreFalse() will not be called. Also, by putting the checking in a method, the code intent should be easier to see two years from now when no one remembers what we were doing.

METHOD PRIVATE AllAreFalse : BOOL
VAR
   i : INT := 0;
   Check : BOOL := TRUE;
END_VAR
WHILE Check DO
   IF myArray[i] THEN
      //this one is true - stop checking
      AllAreFalse := FALSE;
      Check := FALSE;
   ELSE
      IF i <= c_max THEN
         i := i + 1;
      ELSE
         //end of array - all were false
         AllAreFalse := TRUE;
         Check := FALSE;
      END_IF
   END_IF
END_WHILE

(This is an example of how our company would solve this as we are trying to follow the PLCopen programming recommendations, which suggests not exiting early out of FOR loops and always show the ELSE, even if it is empty to make the "intent" clear).

Defining Arrays.

2020-02-27T13:52:57.899000Z

Yes! That works!
Thanks a lot!

Best regards,
Chiavo

Defining Arrays.

2020-02-27T13:52:57.669000Z

Hi drChaivo,

If I correct understand what you want than is this the solution:

VAR CONSTANT
   c_min : INT := 0;
   c_max : INT := 5; 
END_VAR
VAR      
   iIndex : INT;
    idoThisCounter : INT;
   iItemsFalseCounter : INT;
   xTriggerOneTime : BOOL;
   myArray : ARRAY[c_min..c_max] OF BOOL; 
END_VAR

iItemsFalseCounter := 0;
FOR iIndex := c_min TO c_max BY 1 DO
   IF myArray[iIndex] THEN
      xTriggerOneTime := TRUE;
      EXIT;
   ELSE
      iItemsFalseCounter := iItemsFalseCounter + 1;
   END_IF
END_FOR
IF iItemsFalseCounter = (c_max+ 1) 
   AND xTriggerOneTime
THEN
   xTriggerOneTime := FALSE;
   idoThisCounter := idoThisCounter + 1;
   doThis();
END_IF

Regards, Bakkertje

Defining Arrays.

2020-02-27T13:52:57.490000Z

Hello Bakkertje,

I just need to call the DoSomething() one time, but just if all the values are false.

For example,

if I have in my array two values that are true (i.e. myArray[2] := TRUE and myArray[4] := TRUE) then I have to change this two values to false. This means that if I just change one value (i.e. myArray[2] := FALSE) DoSomething() is NOT called. DoSomething() will be called just if the other value is also FALSE. (i.e. myArray[4]:= FALSE ... called DoSomething()...)

Defining Arrays.

2020-02-27T13:52:57.307000Z

Hi drChiavo,

Do you need this each PLC cycle that for each value that is false the "doThis();" is called?
Or only it one time for each value that is changed from TRUE to False?

Defining Arrays.

2020-02-27T13:52:57.092000Z

Hello Bakkertje,

Yes, I have used "EXIT;". What I want to do is to call a function if all the values are FALSE.

For example,

VAR CONSTANT
   c_min : INT := 0;
   c_max : INT := 5;
END_VAR
VAR      
   i : INT;
   xAllFalse : BOOL;
   myArray : ARRAY[c_min..c_max] OF BOOL := [TRUE,FALSE,TRUE,FALSE,TRUE];
END_VAR

So just if all are "FALSE" THEN.. DoSomething()... but the values change during the RunTime. I used your method but it just works for the first value. This means that when I change the first value of myArray[0] to "FALSE" then the function DoSomething() is called and it should be just called if myArray[2] and myArray[4] are also FALSE.

Defining Arrays.

2020-02-27T13:52:56.512000Z

Hi drChiavo,

That is strange I test it and I see no problem.
Did you use the "exit;" to jump out the FOR loop?
When you don't use this in your code the result depends only on the last item of the array.
When you don't use this in my code you are checking always all item of the array, which is not necessary.

Defining Arrays.

2020-02-27T13:52:56.329000Z

@Bakkertje - Thanks for your answer but same result. Not working.

Defining Arrays.

2020-02-27T13:52:56.099000Z

Try this:

VAR CONSTANT
   c_min : INT := 0;
   c_max : INT := 5; 
END_VAR
VAR      
   i : INT;
   xAllFalse : BOOL;
   myArray : ARRAY[c_min..c_max] OF BOOL; 
END_VAR

xAllFalse := TRUE;
FOR i := c_min TO c_max BY 1 DO
   IF myArray[i] THEN
      xAllFalse := FALSE;
      exit;
   END_IF
END_FOR

Defining Arrays.

2020-02-27T13:52:55.849000Z

Hello,

How do I check if all the values in an array are FALSE?

VAR
        myArray : ARRAY[0..5] OF BOOL;
   i: INT;
   xAllFalse: BOOL;
END_VAR
IF myArray[0] = 0 AND myArray[1] AND .... THEN
       doThis();
END_IF

I was trying to do this but it didn´t work.

FOR i := 0 TO SIZEOF(myArray) BY 1 DO
   IF NOT myArray[i] THEN
      xAllFalse := TRUE;
   ELSE
      xAllFalse := FALSE;
   
   END_IF
END_FOR

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