Peter,

It looks like the original formula would have been

y = 0.2923x - 134.39

With a few extra decimal places.

But since you will end up with an integer in the end, you can just round off to -134 for the b parameter (y=mX + b).

For the m parameter, 0.2923 is 2923 ten thousanths. Which is an easy way to remember that you need to divide by 10,000 afterwards.

So you multiply the A/D reading times 2923.
Then divide it by 10,000
Like this...
Code:
X      VAR WORD
Y      VAR WORD

ADCIN 6,X

Y = X * 2923
Y = DIV32 10000
Y = Y - 134
I think that's about as close as you can get with 16/31 bit math.

HTH,