PbPro Maths Help

[retepsnikrep]

Hi,
I don't get it.... $18 and $7F is 24 and 127 respectively. Putting these in the formula should result in "real life values" ranging from -100 to 50 representing the current in amperes, correct?

((0*128)+0-2048) / 20.48 = -100 OK
((24*128)+127-2048) / 20.48 = 56 ??
/Henrik.

Henrik and others thanks for your help.

Sorry yes the maximum value for $18 is actually $17 so thats puts the range covered within -100 to + 50.

That code looks really helpful, and is easily accurate enough, yes the answer is being displayed via a serial lcd device that's not a problem.

The second issue with the seperate lower formula is

Also for a second formula involving BD [2] & BD [3] I need to

(Multiply the right hand digit of 1st hex number by 128, add result to 2nd number)

I'm stuck on extracting a value for the right hand digit of the hex number?

As an aside it may be my formula for BD[2] & BD [3] is incorrect I suspect it should resolve to a number between 0-100% at it represents battery state of charge.
My captured range of values for BD[2] is $21 -$34 and for BD[3] it's again $00-$7F

Ignoring the first digit of BD [2] gives a range of values that seems to work