Convert hex (or byte??) to double

[theodoros]

Hi,

I am terribly sorry but still no lack with that.

I guess you mean to make a formula node?

what kind of input do i provide?

the value i.e. C5D1 is a string as i get it from the instrument.

how do i convert it to a value that i can do calculations with?

i tried "Hexadecimal string to number" and then "Mantissa & Exponent" but i get wrong values.

please help!!

[GerdW]

Hi 21232,

I would convert the string you get into an array of U8. Then pick the needed bytes and do the calculation with them.

I never told to use "Mantissa&Exponent". I gave you formulas to calculate them! You can do the calculation using formula nodes or (my preference) using standard math functions. Try to solve this right now or wait another 2 hours - then I get access to a computer with LabView...

[Yamaeda]

http://en.wikipedia.org/wiki/Single_precision_floating-point_format

Compare that to your 2-bytes and you'll see quite some similarities. The 1st byte is identical between the two and the 2nd byte should be converted to U16, multiplied with 2 (or bit shifted left 1) and insert an empty byte in #2. That should give 4 bytes that can be type converted to a Single Float. (If you really want it in doubles you can do the a type convert again or modify the routine to 8 bytes)

/Y

[theodoros]

ok i converted the string to an unsigned byte array but i am in a dead end still .The array reads 99 53 100 49 .

i will wait for your sollution GerdW.

thanks a lot.

best regards

thodoros

[herrlin]

Example of 2 byte conversion.  Disclaimer this was a quick example, there may be better logic out there.

Dan

[theodoros]

hi herrlin,

thanks for the solution but one quick question,

how do i convert a hexadecimal string to an input for your code

C5D1 is a string that i did not manage to convert to input for your code.

also where is the function for the exponential of 2?i couldn't manage to find it but i did it in a formula node.

cheers

thodoros

[herrlin]

Power of 2 was under Mathematics\Elementary & Special Functions\Exponential Functions directory. Also, once again this is a quick example.

[theodoros]

thanks it works perfectly!

and for a 4 byte number?

i.e. CAEF5DCE what changes should i do?

cheers

thodoros

[GerdW]

Hi 21232,

as you now have the code for 2 byte FPL and the description how to calc 4 byte FPL don't you want to learn LabView and change the given code to fit your needs on your own???

Come on, give it a try!

Hint: finding functions is easy using quickdrop <Ctrl>-<Space>

Message Edited by GerdW on 03-09-2010 05:55 PM

[theodoros]

ok i will

thanks

i am still trying to figure out what the first code does though.

i have zero experience in hexadecimal data manipulation.

i will give it a go but i hope if i don't manage you could give me a push.

thanks again

thodoros