Xylem DH-21 - Manual (Page 73)

DH-21
Using the Graphical “W ATER LOG” Software 4-27
4.4.4.1 Pressure Coefficients Option
The User Defined Pressure Coefficients Option shown in Figure 4-15 allows you to modify the
level or pressure coefficients and the units label. The equation for the temperature conversion has
the following form.
Units = (X) * (Slope) + (Offset)
Units: The user preferred unit of measure. Examples are feet, meters, inches, PSI or whatever
you prefer.
X: This is the default value returned from the sensor in PSI.
Slope: This is the M factor of the standard Y = MX + B equation. It represents a 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 sea level.
When entering this option, the values will reflect the last valid setting used for pressure. For
example, if the predefined “Feet” option was the last valid selection, then under “User Defined”
the units would be “Feet”, the Offset would be 0.0 and +2.308613 would be the slope. The
conversion from PSI to feet is: FEET = PSI * 2.308613 + 0.0, using a latitude of 40 , an
elevation of 1000 Meters above sea level, and a media density of 999.972 Kg/M^3.