Scaling and offset of a sensor

[Ioannis]

I think I got it.

My sensor is read at channel 0. So:

offset    var    word
sensor    var    word

offset_store:         'offset processing
    adcin 0,offset
    write 0,word offset
return

read_pressure:
    adcin 0,sensor
    sensor=sensor-offset
    sensor=sensor*1023/(1023-offset)
return

the problem is how to manage the sensor*1023 since the result might be more than a word and I'd prefer not to use LONG.

But the 1023/(1023-offset) ends up in a small number like 1.62 or similar. It is not known untill the offset is measured and cannot be substituted as a constant and use */ operator.

Ioannis

[Ioannis]

RTFM once again.

Well, DIV32 is the magic trick.

I used a dummy var to make the sensor*1023 multiplication, saved the 1023-offset to range variable and did a div32 range.

Solved.

Ioannis