7 re-calibration, References – Campbell Scientific CS110 Electric Field Meter User Manual
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CS110 Electric Field Meter
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10.7 Re-Calibration
Re-calibration of measurement instruments is commonly done in data critical
applications in order to combat component drift with time. Component drift is
a function of the environment experienced by the instrument. High humidity
and/or high temperature environments generally cause the most drift. For the
CR1000 datalogger a two year re-calibration interval is recommended, with
longer intervals being sensible for users that find negligible instrument drift
over a two year period. The embedded CR1000 datalogger inside the CS110
case should experience a low-humidity environment, which helps minimize
datalogger measurement drift.
As mentioned in Section 5.1, each CS110 is factory calibrated in the parallel
plate calibrator illustrated in Figure 5 to determine individual instrument gain.
The CS110 electric field measurement instrument gain is a function of
electrode dimensions, along with the 1% feedback capacitor used in the charge
amplifier. While measurement drift of CR1000 is likely negligible with regard
to the
±5% of reading accuracy specification of electric field measurements,
datalogger drift may be a factor for the measurement of temperature by means
of an external temperature and RH probe.
A parallel-plate calibration is recommended whenever any electrodes are bent,
removed or replaced, with the exception of the removal and replacement of the
same stator during the process of insulator cleaning. For CS110 applications
requiring long-term electric field measurement accuracy better than ± 10%, a
parallel plate factory calibration is recommended every three years.
The expected lifetime of the CS110 is 5 to 10 years, again depending upon the
operational environment. Instruments operated in coastal environments will
likely suffer from external finish degradation and/or operational failure sooner
than instruments operated in dry inland environments.
11. References
“Lightning Physics and Effects” by Vladimir A. Rakov and Martin A. Uman,
Cambridge University Press, 2003.
“The Electrical Nature of Storms” by Donald R. MacGorman, and W. David
Rust, Oxford University Press, Inc., 1998.
“On some determinations of the sign and magnitude of electric discharges in
lightning flashes” by C.T.R. Wilson, Proceedings of the Royal Society, Series
A, Vol. 92, 555-574, 1916.
“Industrial Electrostatics – fundamentals and measurements” by D.M. Taylor
and P.E. Secker, John Wiley & Sons Inc. 1994, pg. 36-38.
(LPLWS) METEOROLOGICAL\CCAFS\81900\LAUNCH PAD
LIGHTNING WARNING SYSTEM
(
).
Please note that the web site address is case sensitive.
NOAA
NAVSEA OP 5, Vol 1, Seventh Rev. Para 6-2, pg 6-1 and 6-2, 2001.