dynamic pressure measurement using charge amp

[jon80]

Hi All,

I'm measuring an oscillating pressure (approx 0-100 bar) at 20Hz using a piezo electric pressure transducer and charge amp. The output signal shape is fine, however its not where expected vertically, i.e. its oscillating between -5V and 5V instead of 0-10V. What is the cause of this or is it inherent in the piezo - charge amp equipment?

Many thanks,
Best Regards.

 

[IRstuff]

Is the amp AC coupled?

TTFN

 

[Skogsgurra]

As you know, a piezoelectric transducer cannot deliver a static signal. And the charge amplifier (an integrator) has a weak DC restoring feed-back. So, your mean output signal is always zero. In other words, your signal SHALL move between the -5 and +5 volts you observe.

If you need to conserve DC level, you need to measure with another pressure transducer type. Solid state strain gauge types are cheap, fast and accurate. And they also deliver static pressure.

Gunnar Englund

http://www.gke.org

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