NI 9233 Electricity Noise Filtering

[Rafo]

Dear all,

I want to know if there is someway to isolate the NI 9233 (working with the USB 9162) from electrity noise. Maybe to conect a wire to "earth" or something .... I am acquiring data with to much electricity noise ....

Thanks,

Rafo 

[Matt_E.]

Hello Rafo,

Reducing noise in your measurement depends a lot on what the source of the noise is and the specific setup of your system.  I recommend reading through this short tutorial that goes over different measurement configurations and explains some ways noise can get into your system.

http://zone.ni.com/devzone/cda/tut/p/id/5362

Also there is a discussion of DC offset and AC noise problems related to USB measurements located in the High Speed Digitizers help under the topic "Ground Loop Noise in the NI USB-5132/5133".  The grounding setup in this example may be very similar to your configuration.

You can download the High Speed Digitizers help files here:

http://digital.ni.com/manuals.nsf/websearch/BF34033B4168B6CD86257347006D8F45

You can find the topic by opening Digitizers.chm and searching for the topic: Ground Loop Noise in the NI USB-5132/5133

If these sources do not help you please give us more specific information about how your device is connected to your computer and the source you are trying to measure (i.e. types and lengths of cables, desktop computer or laptop, what the source you are trying to measure is and how it is powered etc.)  Also any information on the noise you are seeing would be helpfull such as whether it seems to be related to the A/C power line or another device near your measurement.

-Matt