Level; Pressure Calibration; Barologger - Solinst Levelogger Series User Manual

Levelogger User Guide - Software Version 3.2.3 or Higher

1.1 Level

The Levelogger Gold and Levelogger Junior use a high quality piezoresistive silicon
pressure transducer packaged in 316L stainless steel housing. It gives high accuracy
and high stability. The Levelogger Gold body is coated with Zirconium Nitride (ZrN) to
give corrosion resistance. All Leveloggers measure total or absolute pressure. When
the Levelogger is operating in open air, it is recording barometric pressure and
converting that pressure reading to its water level equivalent above the datalogger's
pressure zero point of 950cm (31.17ft). When submerged, it is recording the
combination of barometric pressure and water pressure. The Levelogger converts the
total pressure reading to its corresponding water level equivalent. Actual water level is
obtained by compensating for barometric pressure. The best method to compensate
for barometric pressure is to employ a Barologger above the water level, somewhere
on site, to obtain records of barometric pressure. The Levelogger Software includes
a Barometric Compensation Wizard, which guides the user through the automated
process of barometric compensation. Manual methods can be employed to determine
the absolute water level using barometric records collected on-site or available from a
local weather station (i.e. Airport). Water level readings from the Levelogger Gold and
Levelogger Junior models are temperature-compensated.

1.1.1 Pressure Calibration

The Levelogger Gold and Levelogger Junior are calibrated against a range of set
reference points to an accuracy of 3 decimal places. The units of pressure are in
pounds per square inch. The conversion factor for pounds per square inch relates to
pressure as follows:
1 pound per square inch = 0.0689476 bar
During the calibration procedure, the Levelogger is fully submerged in a highly
accurate water bath. The bath is set to 15°C and allowed to stabilize.
The pressure is then calibrated to six separate pressure points covering the
entire range of pressure for that particular Levelogger to check for any
non-linearity. The process is repeated again at 35°C to check for temperature
effects. Once done, the Levelogger is approved after all specifications for
accuracy, precision, stability and hysteresis have been met.

1.2 Barologger

The Barologger Gold is designed for use in air only. It has a small range and firmware
algorithms based on air pressure rather than water pressure.
Barologger less accurate if used in water, but more accurate if used as intended, in air.
Using a Barologger is the most accurate and convenient method of obtaining
atmospheric pressure. When programmed with the same sampling parameters as the
Leveloggers on site, a Barologger can avoid barometric data time lags and any errors
introduced due to moisture buildup, kinking or damage to vented cable.
The Barometric Compensation Wizard in the Levelogger Software simplifies the
adjustment of the level measurements for barometric pressure changes, by using the
synchronized data from all Leveloggers on site and the site Barologger.
= 0.703070 m
= 6.895 kPa
= 2.31 ft. H 0 @ 4°C.
2
Page 9
This makes the