HP203B Datasheet, PDF (12/18 Pages) List of Unclassifed Manufacturers – PRECISION BAROMETER AND ALTIMETER SENSOR

DataSheet
HP203B
P_local has unit in mbar, A_offset has unit in meter
P_local
A_offset
1000
1001
1002
‐111.18 ‐102.73 ‐94.29
1003
‐85.85
P_local
A_offset
1004
‐77.43
1005
‐69.02
1006
‐60.62
1007
‐52.23
P_local
A_offset
1008
‐43.84
1009
‐35.47
1010
‐27.11
1011
‐18.76
P_local
A_offset
1012
‐10.41
1013
‐2.08
1014
6.24
1015
14.56
P_local
A_offset
1016
22.86
1017
31.15
1018
39.44
1019
47.71
P_local
A_offset
1020
55.98
1021
64.23
1022
72.48
1023
80.71
P_local
A_offset
1024
88.94
1025
97.16
1026
105.36
If the users find out that the value of P_local is an integer, they can directly obtain the corresponding
altitude offset value in the above table; if the P_local has decimal numbers and the value is larger than P1
and smaller than P2 (P1 ^{and P2 are two adjacent pressure values in the table),} the user shall first
obtain the corresponding altitude offset value A1 and A2 in the table, than use either of the following
two formulas to calculate the desired altitude offset value A:
A = A₁ + 8.326 x (P_local – P₁), or ^{A = A}2 ^{- 8.326 x (P}2 ^{– P}local⁾
For example, the P_local is 1016.4 mbar, which is between ^{1016 mbar (P}1^{) and 1017 mbar (P}2^{). Looking up}
the table, A₁ is 22.86 m and A₂ is 31.15 m. Thus:
A = 22.86 + 8.326 x (1016.4 – 1016) = 26.19 m, or A = 31.15 - 8.326 x (1017 – 1016.4) = 26.15 m
Either of the results is acceptable. After obtaining the value of A, no matter by looking up the table
directly or by calculation, the user shall multiply the A by 100 in order to convert the unit from
meter to centimeter.
Finally, convert the result to a 2’s complement number to obtain ALT_OFF, and fill it into the two
registers. The following table shows 2 examples with the calculated altitude offsets and their
corresponding values to fill into the two registers.
For Example:
Offset
50.02 m
-100.05 m
Hex Value
0x138A
0XD8EB
ALT_OFF_MSB
0x13
0xD8
ALT_OFF_LSB
0x8A
0xEB
6.2 Setup the Events Detection Parameters
6.2.1 PA_H_TH_LSB, PA_H_TH_MSB - (RW)
The two registers form the 16-bit value of PA_H_TH which saves the pressure (or altitude) upper
bound threshold for event detection. When the PA_MODE bit in the INT_CFG register is set to 0, the
contents stored in these registers are the pressure thresholds. Its value should be a 16-bit unsigned
HP203B_DataSheet_EN_V2.0
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