humidity sensor hih 3610

[ajju]

I m making a prog to measure humidity. i m using humidity sensor HIH 3610. I m giving 5 v dc supply.

When i m measuring o/p by multimeter it is showing 1.9v dc. i m giving this o/p to 9201 analog i/p voltage module. i m connecting this module with cdaq 9172. In daq i m not using any scale or calibration. i m using a formula node . i calculated from somewhere formula  (Vout-0.958)/0.0205. Now it is showing humidity around 45. I dont know wheather it is right or not. I want to know the method how to make formula's based on I/p and O/p range.

[Broken_Arrow]

First, you need to know a few things.

1) What is the voltage at 0% humidity (zero offset)

2) What is the voltage at 100% humidity (full scale).

Get those from the datasheet. Looking at your forumula, I'd bet the zero offset is 958mV. The 0.0205 looks odd. That put's your full scale at just 3V.

Anyway...

(full scale - zero offset) * 0.01= slope (or, mV per % of RH)

RH = (V - zero offset) / slope