TECHNICAL
Humidity Measurement using HTM2500
Typical HTM 2500 relative Humidity measurement
100
90
80
70
3
DATA
Relative Humidity (%RH)
60
50
40
30
20
10
0
1000
1500
2000
2500
3000
3500
4000
%RH 0.03 V Vout
0.0375
from 10 to 95% RH
37.7
with V
out
in mV and RH in %
Output Voltage (mV)
Temperature Measurement using HTM2500 (NTC output values)
Temp in °C
-30
-25
-20
-15
-10
-5
0
+5
+10
15437
+15
R in ohms
169149
125546
94143
71172
54308
41505
32014
25011
19691
15618
Temp in °C
+20
+25
+30
+35
+40
+45
+50
+55
+60
+65
R in ohms
12474
10000
8080
6569
5372
4424
3661
3039
2536
2128
2
12379
Suggested application
Steps of 1% RH are achievable
by using 8-bit A/D.
If more resolution is required
a 10 -bit A/D needs to be used
and a third display will be added,
giving steps of 0.2% RH
Read AINO
-
-
.
Calculate RH%
using equation
or
using a look up table
Convert RH% to
BCD code
Send data to display
HPC032 Rev. B Jul 2002
HUMIREL [ Humirel ]
