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ACCURACY, RESOLUTION, HYSTERESIS
Quartzdyne downhole transducers offer accuracy of ±0.015%
FS to 0.02% FS depending
upon model. (The accuracy of the standard used
in our calibrations, 0.01% of reading, must be added to these
figures.) Quartzdyne's accuracy specification includes all
sources of error, including the effects of repeatability,
linearity, and hysteresis. This is contrary to most transducer
manufacturers' practices, but we feel it is a better measure
of performance. For example, a separate specifications for
linearity and temperature sensitivity are meaningless, because
the transducer is designed to be used with a digital correction
for linearity and temperature sensitivity.
Each unit is supplied with the unique coefficients which allow pressure and
temperature to be computed from the output signals. This figure
shows the residual error (deviation from the polynomial fit)
of a typical Quartzdyne downhole transducer.
The test data used to compute the coefficients are supplied
with each transducer.
Resolution of better than 0.01 psi with a one second gatetime is typical. Counting frequency
for infinite time will not provide infinite resolution: at some point, noise
may limit useable information. Available resolution of Quartzdyne transducers,
can be 0.001 psi. We recommend gatetimes of
0.1 seconds or more.
The Series DS transducers offer 0.01% FS accuracy, over
the laboratory temperature range of 0 to 40°C
, and 0.02% FS accuracy, over
the field (outdoor) range from -40°C to +85°C.
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