In-Situ TROLL 9500 Operators Manual - Manual (Page 60)

53 TROLL 9500 Operator’s Manual 0095110 rev. 007 01/09
SECTION 7: MONITORING PRESSURE (WATER LEVEL)
4. In the Barometric Correction window, select the type of correction
to be performed:
s
s
all data points in the test file. Units are selectable, and your
entry is checked for validity. For example, in inches of mercury
the valid range is 14.3 to 33.5 (covering altitudes from the Alps
to the Dead Sea). You may not leave this entry blank, because
a fixed value will be needed even with a reference file (next op-
tion, see below) in case the time stamps in the two files do not
completely overlap.
s
BaroTROLL or other PSIA instrument. This becomes the Refer-
ence file from which barometric pressure corrections will be
derived. If the time stamps in the files do not overlap completely,
the fixed value will be applied.
5. To save the corrected data in a new file that will be automatically
named, check the create new file checkbox.
6. Click OK. The correction is performed immediately and the cor-
rected file is displayed.
RECALIBRATION RECOMMENDATIONS
Pressure sensor accuracy can be adversely affected by improper care
and handling, lightning strikes and similar surges, exceeding operating
temperature and pressure limits, physical damage or abuse, as well
as normal drift in the device’s electronic components. Aside from dam-
age to the sensor, the need for factory recalibration is dependent upon
the amount of drift a customer is willing to tolerate. Factory calibration
every 12-18 months is recommended. Contact In-Situ Customer Ser-
vice for information on the factory maintenance and calibration plan.
Calculations of the accuracy drift of the MP TROLL 9500 over time are
contained in the Appendix of this manual. Contact In-Situ Customer
Service for information on periodic check-ups and re cal ibration.
A single fixed correction is applied
to the entire PSIA test file
The content of a reference file of
barometric pressure data is used
to correct the PSIA test file
4
With a check here, the corrected
data is saved in a separate,
automatically named file