voltage across a resisitve sensor

[JerryJin]

I measure the volatge change across a chemcial sensor using a voltage divider circuitry and a NI USB 6341.  The sensor is powered by a 3-v battery. The volatge reading is noisy and affected dramatically by vibrations in the room such as a person walking close to it or tapping the table. How to solve this problem? Is it caused by grounding?

Many thanks for any comments.

[billko]

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@JerryJin wrote:

I measure the volatge change across a chemcial sensor using a voltage divider circuitry and a NI USB 6341.  The sensor is powered by a 3-v battery. The volatge reading is noisy and affected dramatically by vibrations in the room such as a person walking close to it or tapping the table. How to solve this problem? Is it caused by grounding?

Many thanks for any comments.

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I would start by checking all solder joints and terminals.

[JerryJin]

We checked the connections. All have good connections. Problem remains

[vt92]

Have you read the online resources at ni.com?

http://zone.ni.com/devzone/cda/pub/p/id/262

http://www.ni.com/white-paper/3344/en

[johnsold]

From your original post is sounds as though the sensor may be microphonic, that is, the sensor responds to vibrations in addition to the chemical inputs.

Try placing it on some very soft foam or suspend it via rubber bands.  That should isolate it from the vibrations.

Another thing to try is to replace the sensor with a resistor of similar value.  Do you see that same noise with the resistor?

Those two test should allow you to determine whether the sensor or the wiring is the problem.

Lynn