sensor

[chandu13]

hi
aim getting 0-10v from vacuum sensor. It is fluctuating
How to remove the fluctuations from the signal. This signal aim giving to AD571 ADC.
Due to fluctuations display is showing wrong readings.
What hardware I have to use to remove the fluctuations.

Thanks

Regards
chandu

 

[Nigel Goodwin]

A low-pass filter, to average out the fluctuations, you could also do it in software, take a series of readings and average them.

 

[Hero999]

At what frequency is it fluctuating?

Use the following formulat to calculate the desired cutt-off.

[latex]F = \frac{1}{2 \pi RC}[/latex]

 

[chandu13]

precautions

hai

thanks for reply

What precautions we have take while connecting the sensor signals to the

ADCs.

regards

chandu

 

[cadstarsucks]

hi
aim getting 0-10v from vacuum sensor. It is fluctuating
How to remove the fluctuations from the signal. This signal aim giving to AD571 ADC.
Due to fluctuations display is showing wrong readings.
What hardware I have to use to remove the fluctuations.

Thanks

Regards
chandu

A simple resister in series and a capacitor to ground on before the A/D. The values depend on how quick you need it to respond. 10K and 0.1uF will allow your signal to stabilize in 5mS which should be quick enough. depending on your signal you could up the value of one of them 10 times.

D.

 

[chandu13]

impedence matching

thanks for the reply

when we want use LM324 as impedence matching while conecting sensor siganl to ADC.

Regards
chandu

 

[ericgibbs]

hi chandu,

Can you post a drawing showing how you have the sensor connected.?

Is the vacuum pump running while you are sampling the pressure in the chamber ?

EricG

 

[atferrari]

A fluctuation by itself doesnt make to qualify your reading as wrong.

Are fluctuations real? Have you checked that?

If so, better you take them into consideration.

Many parameters of a dynamic system, do fluctuate. What matters also is if you want to record the trend of change or actual values and the time interval between measurmements.