User Manual for AML Oceanographic’s Micro SVT Sensor
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8
CALIBRATION
The instrument was calibrated at the factory at the time of manufacture. This should remain
within published specifications for periods of 1 to 2 years, depending on the amount of use
and other conditions occurring in the deployment environment. The sensor accuracies are
also dependent upon proper care and maintenance by the user. AML Oceanographic
recommends recalibrating the instrument annually, however some standards agencies
specify semi-annually for all sensors used in bathymetry work. Re-calibration of these
sensors must be done at the factory or an authorized service facility. Contact the factory for
the location of the nearest facility.
The Micro Sensors are calibrated by recording the instrument's raw data at known reference
points. This data is applied to a curve fitting algorithm to produce calibration coefficients.
Each set of coefficients are permanently stored in the instrument's memory.
Calibration coefficients are not interchangeable. Each set is unique to each instrument. The
calibration coefficients for the instrument to which this manual belongs are listed in
Appendix `B'. The user will need these coefficients if the instrument is to be used in the
RAW mode for post processing purposes.
8.1
SOUND VELOCITY
The sound velocity sensor is calibrated against a distilled water reference. The following
equations are used to convert raw data to engineering units:
C
r
= 1/(A + B*R + C*R
2
+ D*R
3
)
Where: R = (Nh-Nsv)/(Nh-Nl)
Nh , Nsv, Nl = raw values
A through D are calibration coefficients determined at the factory.
8.2
TEMPERATURE
The temperature electronics use the following formula to convert raw data to engineering
units (ºC):
T = A + B*Nt + C*Nt
2
+ D*Nt
3
+ E*Nt
4
+ F*Nt
5
Where: T = temperature in ºC.
Nt = raw value
A through F are calibration coefficients determined at the factory
