Hope RF
HP01-TQ
Version: 2.1
BAROMETER MODULE
2010-6-3
PRELIMINARY
Pressure Measurement
The main function of HP01 system is to convert the uncompensated pressure and
temperature signal from a pressure sensor. After the conversion, the following two values
can be obtained:
. measured temperature
. measured pressure
“D2”
“D1”
As the sensor is strongly temperature dependent, it is necessary to compensate for these
effects. Therefore necessary temperature compensation is needed to achieve nominal
accuracy.
Pressure and Temperature Compensation Calculation:
The following information is just a guide line for temperature
compensate, the end user of this module should not be confined
to this method. Many other methods can be deployed to achieve
best accuracy.
Step 1: (set relative pressure starting reference point, normally this step be done after
power up or reset relative pressure)
P0=1013.2hp
D1(P0)=D1
D2(P0)=D2
Step 2: (normal pressure calculation with first order temperature compensation)
dUT=D2-D2(P0)
dTCS=TCS*dUT
dUP=D1-dTCS-D1(P0)
P2=dUP/SNS
; calculate current temperature difference with reference temperature
; calculate compensated pressure offset with temperature coefficients
; calculate temperature compensated pressure reading
; calculate pressure difference referred to starting pressure P0
; calculate current relative pressure
P=P0+P2
Example:
D1(P0)=30000
D2(P0)=4100
TCS=-0.55
SNS=27
(obtained after power up reading: D1)
(obtained after power up reading: D2)
(nominal module value from this data sheet)
(nominal module value from this data sheet)
D1=30036
D2=4107
(current pressure AD reading from module)
(current temperature AD reading from module)
dUT = 4107-4100 = 7
dTCS=-0.55*7=-3.85
dUP=30036+3.85-30000=39
3
HOPERF [ HOPERF ]
