E10160-200722
FOP
Page 12
Now I can compute the corrected pressure using the formula.
P
corr
= (P
rec1
- P
rec0
) - CT (T
1
– T
0
) - (B
1
- B
0
)
P
corr
= (514.28
– 99.56) – (-0.0422) (25 – 20) - (101.3- 100.2)
P
corr
= 414.72 + 0.211
– 1.1
P
corr
= 413.831 kPa
2.7 Linear pressure equation for piezometers with gauge factor 0001000
For piezometers with linear equation you can assign the gauge factor 0001000 and
convert the reading using the equation below. With this method also you assign always
the same gauge factor in the readout unit and you record always the reading in raw units
in nanometers (nm).
The calibration factor (CF) is obtained using a linear regression. Then to convert changes
in readings (internal unit in nm) to changes in pressure use the following equation:
SI units (kPa)
P
rec
= CF x (L
1
– L
0
)
And
P
corr
= P
rec
- CT (T
1
– T
0
) - (B
1
- B
0
)
where:
P
corr
= corrected pressure in kPa
P
rec
= recorded pressure in kPa
L
o
L
1
= Initial (at installation) and current readings (nm)
B
o
B
1
= Initial (at installation) and current barometric pressure in kPa.
CF
= Calibration factor in kPa/nm
CT
= Temperature correction factor in kPa/
o
C
T
o
T
1
= Initial (at installation) and current temperature readings (
o
C)
CF and CT are defined on the calibration data sheet provided with each sensor.