Don,
   You can still do this with a intelligent version of fixed point..
Just use say ten bytes before and ten after the decimal point.. (or more
or less for either side, whatever the max possible range is plus some
for loss.)  Then just have the fixed mult skip all zero bytes and the
routine won't take very much longer than a dedicated routine for a set
number of signifigant bytes.  Since your sensors have the constants with
them the input is easy to put into the right place, and the fixed point
output is easy to sift through from MS byte to LS byte and set the scale
by where the numbers start poping up..

Alan


>
> Thanks for your reply to my query, Michael. My original posting
> described a situation where fixed point calculations were not
> suitable because the translation equations (and therefore the numeric
> ranges) weren't known in advance. I'm working on a project at the
> moment where user-replaceable sensors are plugged into a base unit;
> each sensor having a 40-byte EEPROM (Dallas 24A30) containing the
> sensor name (ie, LCD text string) and calibration constants, etc. The
> main controller is not a PIC, but only because of the lack of
> floating point support in the programming tools.
>