Pressure Calibration Uncertainty Constraints

Hi Justinanto1987,

By uncertainty do you mean the error?

You will need a dead weight tester to check the gauges (expensive)

Gauges come in various accuracies, 2.5%, 1.6%, 1% etc. so you will need to check whether it is still within the original specification and supply a calibration certificate showing the deviation from the pressure shown both on rising and falling pressures.

Calibration of equipment is usually carried out by specialist companies due to the cost of the equipment required.

John

You need to be more specific as to what "uncertainty" is.

There is a wide range of variables that may need to be considered such as:

Unknown system dynamics?

Unknown physical state of the pressure gauge due to poor maintenance or exposure to forces beyond design specifications?

Determine all system dynamic(s) concerns, operating constraints, operating environment, gauge location in system, type of gauge, temperature, age, accuracy required, operating characteristics, and the requirements of the application.

In short you must know the process very well that the gauge is being used in/on before you can answer the question.

The calibration uncertainty will depend on the calibration method, and the uncertainties in the components you are using to perform the calibration. As jesw55 said, the "proper" way (giving least uncertainty) would be with a dead-weight rig, but buying one for only a few instruments doesn't make economic sense.

Compare what you wish to test to a known +/- accurate gauge...

http://www.ashcroft.com/products/pressure_gauges/test/upload/BigGauge-I-M.pdf

We collectively bow to your uncertainty.....

..

You forgot "High" in front of Uncertainty but I will accept never the less !

Although seldom I see that High value is recognized at least

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DHAYANANDHAN.S

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ha ha, thanks for your help. I already consider the uncertainty from the master, uncertainty due to resolution ,uncertainty due to hysteresis and uncertainty due to repeatability for uncertainty budgeting. I wonder whether I have to consider more constraint for my budgeting be more correct. That is why I asked this question.

Is it practical to find the uncertainty due to other parameters like humidity and temperature ? How we can find the same practically ?

By making measurement at different temperature and humidity values and compare results in order to establish a trend.

"Gentlemen I am sorry to say that you are by far not up to date with measurement techniques and definitions."

If I know all, why should I post such a question here. Unnecessary statement!!!

http://pioneer.netserv.chula.ac.th/~tarporn/2141375/HandOut/Uncertainty.pdf