SCL Progam

Berra · Jun 4, 2010

Hi

I whant to check out if the first bit ( can be changed to second bit) in a woord is set to one,
I have a db with 100 words.

case first bit OF
1:
for INDEX := StartAdressDB TO StoppAdressDB

IF StartAdressDB OR StoppAdressDB = W#160000_0001 Then
OutPut = 1;

else

End_if

End_Case

But it says ERROR: You most use a Bool in a IF statment, Are they some other way to compare bit in woord in a FOR LOOP????

// Berra

JesperMP · Jun 4, 2010

Change
IF StartAdressDB OR StoppAdressDB = W#160000_0001 Then

to
IF (StartAdressDB = W#160000_0001) OR (StoppAdressDB = W#160000_0001) Then

It will make that particular error message go away. Dont know if the rest of the code is OK.

I dont know what you are trying to do, but it does not look pretty.

TurpoUrpo · Jun 4, 2010

He says he wants to check first bit in a word if its 1. But that code wont do anything like that...

This one would do it:

Code:

FUNCTION CheckFirstBitInWord : BOOL

VAR_INPUT
    WordToCheck : WORD;
END_VAR

    IF ((WordToCheck AND w#16#0001) <> w#16#0)
    THEN
        CheckFirstBitInWord := True;
    ELSE
        CheckFirstBitInWord := False;
    END_IF;
    
END_FUNCTION

Peter Nachtwey · Jun 4, 2010

The easy and fastest way is to convert the WORD to INT and check if negative
IF WORD_TO_INT(Word2Check)<0 THEN
// BIT SET
ELSE
// BIT CLR
END_IF

TurpoUrpo · Jun 4, 2010

That would check last bit wouldn't it. I have another idea too, but need to confirm it first.

Berra · Jun 4, 2010

Yes TurpoUrpo thats right, but i also whant to loop from db100.dw0 to db100.dbw200 and check evrey word.

So i think i must have a for loop with some Index, ot to you have a better idea ???

// Berra

L D[AR2P#0.0] · Jun 4, 2010

What result do you require, an array of 100 bits with TRUEs and FALSEs in it indicating if the WORD meets the test ?

Berra · Jun 4, 2010

hrm, the first bit in evrey word is a alarm bit, so if the first word has the first bit set i whant to show that as 1 in a output. And so if the first bit in the first word is false and the first bit in db100.dbw200 is true. I whant the same output to show one.

I hope you understand

regards

// Berra

L D[AR2P#0.0] · Jun 4, 2010

If the first bit in any of the 100 words in the DB is true then the function should return true ?

TurpoUrpo · Jun 4, 2010

Here another one, with example call with for loop (i assumed you could do it yourself with first function I introduced)

Code:

FUNCTION CheckBitInWord : BOOL

VAR_INPUT
    WordToCheck : WORD;
    BitToCheck : INT;
END_VAR
VAR_TEMP
    WordTemp : WORD;
    BitsInWord AT WordTemp : ARRAY[0..15] OF BOOL;
END_VAR

WordTemp := WordToCheck;
CheckBitInWord := BitsInWord[BitToCheck];
    
END_FUNCTION


FUNCTION BitInWords : VOID

VAR_TEMP
    i : INT;
END_VAR

FOR i := 0 TO 99 DO
    "AlarmBits".AlarmArray[i] := CheckBitInWord(WordToCheck := DB5.dbw[i*2], BitToCheck := 0);   
END_FOR;
 

END_FUNCTION

TurpoUrpo · Jun 4, 2010

This one does it too, if you need to check least significant bit in word

Code:

FUNCTION CheckBitInWords : VOID

VAR_TEMP
    i : INT;
END_VAR

FOR i := 0 TO 99 DO
    "AlarmBits".AlarmArray[i] := WORD_TO_BOOL(DB5.DBW[i*2]);  
END_FOR;
 

END_FUNCTION

If you need to check other bits, you can just use SHR to have correct bit in place of least significant bit.

Like this :

Code:

FUNCTION CheckBitInWords : VOID

VAR_TEMP
    i : INT;
END_VAR

FOR i := 0 TO 99 DO
    "AlarmBits".AlarmArray[i] := WORD_TO_BOOL(SHR(IN:=DB5.DBW[i*2],N:=8));  
END_FOR;
 

END_FUNCTION

I came with this idea righ after preceding post. I think this one is lot better.

Berra · Jun 4, 2010

yes thats right L D [AR2,P#0.0], but i think i can use TurpoUrpo code and modificate it.

Thanks TurpoUrpo

// Berra

TurpoUrpo · Jun 4, 2010

Code:

FUNCTION CheckBitInWords : BOOL;

VAR_TEMP
    i : INT;
END_VAR

FOR i := 0 TO 99 DO
    IF (WORD_TO_BOOL(DB5.DBW[i*2]) = True)
    THEN
        CheckBitInWords := True;
    END_IF;
END_FOR;

END_FUNCTION

I think ill do tomorrow version that accepts byte, word or dword input and checks designated bit. Its nice execrice for me.

It might work like this also, Ill test it too tomorrow.

Code:

FUNCTION CheckBitInWords : BOOL;

VAR_TEMP
    i : INT;
END_VAR

FOR i := 0 TO 99 DO
    IF (WORD_TO_BOOL(DB5.DBW[i*2]))
    THEN
        CheckBitInWords := True;
    END_IF;
END_FOR;

END_FUNCTION

L D[AR2P#0.0] · Jun 4, 2010

You forgot this:

Code:

FUNCTION CheckBitInWords : BOOL;

VAR_TEMP
    i : INT;
END_VAR
[COLOR=Red]CheckBitInWords := False;[/COLOR]
FOR i := 0 TO 99 DO
    IF (WORD_TO_BOOL(DB5.DBW[i*2]) = True)
    THEN
        CheckBitInWords := True;
    END_IF;
END_FOR;

END_FUNCTION

TurpoUrpo · Jun 4, 2010

Oops

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