Using the CS400/CS405 Submersible Pressure Transducer with Campbell Scientific Dataloggers
6
Factory calibration: Each CS400/CS405 transducer is shipped with a
calibration report specific to that unit. The report specifies calibration
conditions and actual data reflecting the transducer's static accuracy and
thermal characteristics. Newer calibration reports from KPSI include a slope
figure near the bottom of the page that may make the following calculations
unnecessary.
Short Cut users may need to divide the KPSI calibration slope
figure by 2.3065 to obtain PSI/mV for use in the Short Cut
CS400/CS405 setup screen.
The following is an example from a five psi CS400 calibration report:
Test
BFSL
(BFSL = Best Fit Straight Line)
Pressure
Room Temperature
PSIG
Outputs
0.0001
0.01
1.0002
4.30
1.9997
8.59
2.9996
12.87
3.9996
17.16
5.0006
21.45
To determine a multiplier based on the two calibration end-points:
Multiplier
(5.006 PSI - 0.0001 PSI) 2.3065 ft / PSI
21.45 mV - 0.01 mV
0.5380 ft / mV
=
∗
=
BFSL output at full scale pressure
BFSL output at min. scale pressure
Full scale pressure
Minimum scale pressure
Density factor
(e.g., feet of water/PSI)
A second way to calculate the multiplier is to run a linear regression on the data
from the factory calibration report. In the regression, the BFSL output in mV
would be the x axis or independent variable and test pressure in PSI the y or
dependent variable. The slope would equal the multiplier and the intercept
would be the offset.
Field calibration: If you do not have a factory calibration report, a multiplier
can be determined by performing a field calibration. Wire the transducer and
program the datalogger as described, using a multiplier of 1.0 and an offset of
zero. Watch the measurement results using Mode *6 on the keyboard/display
or the monitor mode on an attached computer. Record the CS400/CS405 signal
output at two separate depths.
NOTE
Содержание KPSI Series
Страница 2: ...This is a blank page ...
Страница 4: ...This is a blank page ...
Страница 6: ...This is a blank page ...
Страница 18: ...Using the CS400 CS405 Submersible Pressure Transducer with Campbell Scientific Dataloggers 12 ...