44
Level
trOll
Operator’s Manual
0052210 rev. 006
With vented or “gauged” pressure sensors, a vent tube in the cable
applies atmospheric pressure to the back of the strain gauge. The basic
unit for vented measurements is
PSIG
(pounds per square inch “gauge”),
measured with respect to atmos pheric pressure. Vented sensors thus
exclude the atmospheric or barometric pressure component.
This difference between absolute and gauged measurements may be
represented by a simple equation:
P
gauge
= P
absolute
- P
atmosphere
preSSure, depth, and LeveL
Output options for pressure measurement are completely software-
selectable. Each log configuration presents the following choices:
• Pressure in PSI or kPa
• Depth in feet or meters
• Water Level with a reference (an “offset”)
4
Surface Elevation reference
4
Depth to Water (drawdown) reference
Pressure is a simple check box. For depth or level, the software presents
additional options:
• The type of Level measurement you wish to log
• The Level Reference you wish to use
• The type of water you will be monitoring in (fresh, brackish,
or saline). Or choose the
Advanced
button for a pressure-to-
level conversion that compensates pressure readings for fluid
density, latitude, and elevation
seCtion 5: pressure/LeveL
TIP:
For more on
the differences
between
Absolute (non-vented) and
Gauged (vented) sensors,
see the technical note
on the In-Situ software/
resource CD, or the
Downloads section of the
In-Situ web site at www.
In-Situ.com
.
