LeveLine
®
Instruction Manual
10401-01026 Rev D
2.11.3. Baro Correction Overview
In the Baro Correction frame, you have a choice of 'None', 'Logged Zeros', 'Baro File' or
'Fixed'. If you do not want to correct for barometric pressure, select 'None'.
2.11.3.1. Logged Zeros Baro Correction
Logged zeros are pressures that were logged during manual deployment with either a
QuickDeploy
™
Key or a LeveLine
®
Meter
whilst the logger was out of the water
. These
pressures represent the barometric pressure at the exact time of deployment (or the zero
offset in the case of a vented logger) and can therefore be used to apply a zero offset to the
level. When Level Logger Data has been uploaded, any record that is a Logged Zero, will
appear with a corresponding 'Z' in the Zero column as shown in the example below.
Selecting the 'Logged Zeros' baro correction option will use these pressures to apply an
offset to the data points. This offset will make the level read zero each time a logged zero
point appears in the data. Subsequent data points will be offset by a corresponding amount
thereby correcting them for the atmospheric pressure prevalent at the instant of
deployment.
If your data was logged using a GAUGE (vented) type Level Logger, this is the only
relevant Baro Correction option (other then 'None), and serves to zero any slight offset or
zero drift in the Gauge type sensor.
2.11.3.2. Baro File Baro Correction
If your data was logged using an ABS (absolute) type Level Logger and you have an
associated Baro Logger file loaded, the 'Baro File' option should be used. This will
automatically associate the Water Level data and Baro data files and correct the water level
for changes in barometric pressure.
If you chose this option, the barometric pressure data logged by the Baro Logger must
coincide time-wise with the level data you are trying to correct.
2.11.3.3. Fixed Value Baro Correction
If your data was logged using an ABS (absolute) type Level Logger and you do not have an
associated Baro Logger file loaded, you can apply a fixed barometric correction by ticking
the 'Fixed' box and inserting a fixed barometric pressure. This option can also be used to
correct for any zero offset present when using a Gauge (vented) type Level Logger.
2.11.4. Water Density Correction
When calculating the level of water based on water pressure, it is essential to know both
the temperature and the salinity of the water in question. These two factors affect the
density of the water and therefore the amount of pressure that water will exert on a
pressure sensor at any given level.
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®
Ltd.
www.aquaread.com
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