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

0

10

20

30

40

50

60

70

80

90

100

1000

1500

2000

2500

3000

3500

4000

Output Voltage (mV)

%RH

0.03 V

out

from 10 to 95% RH

Read AINO

Convert RH% to

BCD code

Send data to display

Calculate RH%

using equation

or

using a look up table

2

12379

0

10

20

30

40

50

60

70

80

90

100

1000

1500

2000

2500

3000

3500

4000

Output Voltage (mV)

%RH

0.0375 Vout

37.7

from 10 to 95% RH

Typical HTM 2500 relative Humidity measurement

Humidity Measurement using HTM2500

Temperature Measurement using HTM2500 (NTC output values)

Temp in °C

R in ohms

Temp in °C

R in ohms

TECHNICAL

DATA

3

-

-

.

HPC032 Rev. B Jul 2002

15437

-25

125546

-30

169149

-20

94143

-15

71172

-10

54308

-5

41505

0

32014

+5

25011

+10

19691

+15

15618

+20

12474

+25

10000

+30

8080

+35

6569

+40

5372

+45

4424

+50

3661

+55

3039

+60

2536

+65

2128

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