Campbell Scientific AVW1 and AVW4 Interfaces for Vibrating Wire Sensors - Manual (Page 6)

AVW1/AVW4
1-2
be placed at the desired level and allowed to
come to temperature equilibrium with its
surroundings (5 minutes or more). The
multiplier determined in equation 3.2-2 should
be entered and 0.0 should be entered for the
offset. After the temperature and the reading
has stabilized, determine the value that would
have to be added to the reading to obtain the
measured level. Enter this value as the offset.
In some cases there is no measured reference.
In order to obtain the correct offset under these
conditions, lower the sensor to a point just
above the water level and wait 5 minutes. Use
the multiplier, an offset of 0.0, and the
temperature correction function determined in
Sections 3.2 and 3.5 to obtain a reading.
Record the reading. Solve equation 3.2-3 for
the new offset by plugging in the "reading" in the
place of the "[Gage Factor * Zero Reading]" and
the "Barometric Pressure" from an accurate
barometer or a reference sensor in the place of
"Po" unless it is a vented sensor then use 0 in
the place of "Po". Enter the new offset.