NOT function wrong behaviour

[caracasnet]

HI everyone,

I have been trying to get the opposite value of a binary channel using NOT function and i don't get the right values.

i'm extracting bits from a word with GetB

then i have to use CTNV to clean the NOVALUE data because of the malfunction of the GetB (already corrected for Diadem 2012 but not for my 10.2)

and at last i will like to get the invert value so: 0 will be 1 and 1 will be 0

These is the code that i'm using and the results:

Call ChnCalculate("Ch(""[1]/CHFS Bit 0"")=GetB(Ch(""[1]/CH 2 CHFS""),0)")

Call ChnCalculate("Ch(""[1]/CHFS Bit 0"")=Ch(""[1]/CHFS Bit 0"")+CTNV(Ch(""[1]/CHFS Bit 0"")>1)")

Call ChnCalculate("Ch(""[1]/CHFS Bit 0_a"")=NOT (Ch(""[1]/CHFS Bit 0""))")

Results:

1 = -2

0 = -1

i can correct with an offset but will be more time for process the data... and if is a malfunction like in GetB is important to correct too...

I'm doing something wrong or is a real malfunction ?

Thanks in advance

Rafael

[AndreasK · Accepted solution]

Hello Rafael,

the problem here is the assumtion that true is equal 1.

This is not true. In VB true is -1 and in general there is only one real assumtion for bool true which is "true is not false".

MsgBox CInt(true)

==> -1

MsgBox CInt(false)

==> 0

So after changing your formula to

Call ChnCalculate("Ch(""[1]/CHFS Bit 0_a"")=NOT CBool((Ch(""[1]/CHFS Bit 0"")))")

 Your results will go to 0 and -1 which is true and false.

But now your case. Why does NOT 1 result in -2.

Thats easy because its a logical operation to every single bit in the integer number

 1 = 00000000000000000000000000000001
-2 = 11111111111111111111111111111110

You can validate this with the Programmer View of Microsfts calc.exe

NOT 1 also results in -2

So everything is working well. Even if its a little bit unexpected.

Call ChnCalculate("Ch(""[1]/CHFS Bit 0_a"")=Abs(NOT CBool((Ch(""[1]/CHFS Bit 0""))))")

 Results in what you want.

greetings from rainy germany

Andreas

[caracasnet]

I love this Forum....

THANKS a lot for the explanation, i understood perfect, and thanks for the solution too.

I didn't know about the VB true is -1

Until next time.

Rafael