Calibration EMF and Pressure Sensor

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Calibration EMF and Pressure Sensor

This calibration procedure applies to instruments of the laboratory for physical geography of Utrecht University. Be aware that the so called afdeelfactor does not apply to all pressure sensor calibrations. Often, the afdeelfactor is already taken into account in the calibration coefficients provided by the lab and should therefore be left out of the calibration below.

Calibration EMF 147

$u = \frac{U_{\mathrm{cr10}}}{\mathrm{overdracht}} -\frac{\mathrm{offset}}{\mathrm{overdracht}}$

Example

X-direction
Afdeelfactor	0.2482
Overdracht	255.53
Offset	-5.23

$u_{x} = 0.0039 \times U_{\mathrm{cr10}} + 0.020$

Y-direction
Afdeelfactor	0.2485
Overdracht	254.56
Offset	7.01

$u_{y} = 0.0039 \times U_{\mathrm{cr10}} - 0.028$

Calibration Pressure Sensor

$p_{\mathrm{water}} = \frac{\frac{U_{\mathrm{cr10}}}{\mathrm{afdeelfactor}} - \mathrm{Constante}}{\mathrm{Xcoefficient}} - p_{\mathrm{air}}$
Use the Usensor = f(p) regression!

Example

pressure sensor 2774
Constant	-6378.39 mV
Xcoefficient	6.653486 mV/mbar
Afdeelfactor	0.2479

$p_{\mathrm{water}} = 0.6063 \times U_{\mathrm{cr10}} + 958.65 - p_{\mathrm{air}}$

where the unit of water pressure is millibar (mbar)

1 m fresh water:

$\rho_{\mathrm{water}}gh = 1000 \times 9.81 \times 1.0 = 9810 \mathrm{\,N/m^2} = 98.1 \mathrm{\,\, mbar}$

so: 1 mbar = 0.0102 m of fresh water

m salt water:

$\rho_{\mathrm{water}}gh = 1025 \times 9.81 \times 1.0 = 10055 \mathrm{\,N/m^2} = 100.55 \mathrm{\,\, mbar}$

so: 1 mbar = 0.0099 m water

Using this, the calibration becomes approximately:

$\eta_{\mathrm{water}} = 0.006063U_{\mathrm{cr10}} + 9.5865 - 0.01 p_{\mathrm{air}}$

where the unit of the water height is meter (m), and the unit of air pressure is millibar (mbar)

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Calibration EMF and Pressure Sensor