Xylem DH-21 - Manual (Page 75)

DH-21
Using the Graphical “W ATER LOG” Software 4-29
Slope:
This is the M factor of the standard Y = MX + B equation. It represents the rate of change
for a given change of X.
Offset:
This is the B factor of the standard Y = MX + B equation.
The offset can also have a value added to it to allow the results to be referenced to some
other point like freezing or boiling point.
When entering this option, the values will reflect the last valid setting used. For example, if
Celsius was the last valid selection, the units would be “Deg C”, the slope would be “1.0” and
the offset would be “0.0”. These values are straight forward because the sensor returns
temperature in degrees C. If Fahrenheit was selected, the units would be “Deg F”, the slope
would be “1.80” and the offset would be “32”.
To convert to Kelvin use +273.15 for the offset and +1.0 for the slope. Kelvin is equal to 273.15
+ degrees C.
To convert to Rankine use +491.67 for the offset and +1.8 for the slope. Rankine is 459.67 +
degrees F.