How to calibrate different sensors attached with my Micro-controller??

[xpress_embedo]

I am sensing parameters like temperature, pressure, humidity with the help of Different sensors interfaced with a micro-controller available in market.

But to calibrate these all sensors with the well known industry ones.

Is there any well know method to perform all this calculation, to adjust my sensor values with the industry standards.

 

[amendar]

xpress_embedo

Almost all sensors are factory calibrated and have some good information in their datasheets.

May be this will help.

 

[tpetar]

I am sensing parameters like temperature, pressure, humidity with the help of Different sensors interfaced with a micro-controller available in market.

But to calibrate these all sensors with the well known industry ones.

Is there any well know method to perform all this calculation, to adjust my sensor values with the industry standards.

Read sensor datasheet for deviations in measurement. Usually this happen in various temperature ranges.



Best regards,
Peter

 

[andre_luis]

Are you really talking about Calibration or Approval ?


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[xpress_embedo]

Are you really talking about Calibration or Approval ?


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What is the difference between calibration and approval..


Actually i am making a Data Logger, which has temperature sensor, humidity sensor, pressure sensor, tipping bucket for rain fall measurement.
So i need to calibrate it, i don't no, whether they are right or not, specially the humidity and pressure sensor.

I use SHT75 for Humidity measurement and one Rotornics HygroClip2 for Humidity Measurement.

SHT75 humidity is equal to HygroClip2 humidity, but in in SHT75 when we calculate the True Relative Humidity it is different from the Hygroclip2.

I use another device to measure Humidity, which use Wet and Dry Bulb technique and its result is equal to SHT75 True Relative Humidity.
:-(

And how to check whether other sensor are giving proper result or not.

- - - Updated - - -

Are you really talking about Calibration or Approval ?


+++

What is the difference between calibration and approval..


Actually i am making a Data Logger, which has temperature sensor, humidity sensor, pressure sensor, tipping bucket for rain fall measurement.
So i need to calibrate it, i don't no, whether they are right or not, specially the humidity and pressure sensor.

I use SHT75 for Humidity measurement and one Rotornics HygroClip2 for Humidity Measurement.

SHT75 humidity is equal to HygroClip2 humidity, but in in SHT75 when we calculate the True Relative Humidity it is different from the Hygroclip2.

I use another device to measure Humidity, which use Wet and Dry Bulb technique and its result is equal to SHT75 True Relative Humidity.
:-(

And how to check whether other sensor are giving proper result or not.

 

[amendar]

datasheets' nominal values are stated in different temperature, at 23ºC and 25ºC,

as you know, relative humidity depends on the temperature, and we should consider accuracy and tolerance for each...

it seems that the difference is more than the expected values!

how do you calculate relative humidity and how much is the difference,

 

[xpress_embedo]

SHT75 gives SORH as output.
On the basis of which we calculate RH_Linear

and then with the help of time we calculate RH_True
(Please see Datasheet, i am not able to upload anything edaboard due to proxy issue in my place)

So we have two Value RH_Linear and RH_True at 25 C, both RH_Linear and RH_True are same.
But as temperature varies the difference between these two value changes.

Now i have two different things two measure humidity, one is HygroClip2 Sensor and another one is a equipment something like this

**broken link removed**

So the value i obtained from this equipment is equal to RH_True of SHT75 Sensor

and the Output of HygroClip2 is equal to RH_Linear of SHT75.

That's why i am confused which humidity is correct and used in meteorological departments.

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datasheets' nominal values are stated in different temperature, at 23ºC and 25ºC,

how do you calculate relative humidity and how much is the difference,

I am using the formula given in the datasheet to calculate the Humidity, and used this link to write my program

http://embedded-lab.com/blog/?p=2711

http://sites.google.com/site/coolembeddedlaboratory/home/pic18f4550/tutorial-list/sht75-interfacing-with-pic