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Digital Multimeters (DMMs) and Precision DC Sources

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Active Participant GS
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GS
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Can the PXI-4071 average data for 5 minutes?

We need to make a current measurement for at least 5 minutes and average the data. Can the 4071 do this? It looks like the maximum conversion time is 149 sec, but I'm not sure if there's a way to get around that when averaging.

 

George

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Sean_F
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Re: Can the PXI-4071 average data for 5 minutes?

Hi GS,

 

Thanks for posting! If you have a static signal that you're trying to measure for that long I would just recommend taking many 7 1/2 precision measurements and averaging them afterwards. I modified the Cont Acq & Chart Multiple Samples VI (Help » Find Examples » Hardware Input and Output » Modular Instruments » NI-DMM » Multi-Point Measurements) to accept an acquisition time input (see attached). Below is a screenshot of the VI. Hope this helps!

Finite Acquisition DMM Example

Sean Ferguson
Application Engineering Specialist | RF and Reconfigurable Test
Active Participant GS
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GS
Posts: 283
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Re: Can the PXI-4071 average data for 5 minutes?

Thanks. Unfortunately I forgot to mention that the signal has some spikes in it that we need as part of the average. We're thinking we'd need to sample at about 10K to catch them.

 

George

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Sean_F
Posts: 117
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Re: Can the PXI-4071 average data for 5 minutes?

Hi George,

 

If you want to sample that quickly you're going to have to set your precision to 4 1/2 digits. This has to do with the aperature time required to make a measurement at a specified precision. You can find more information on the 4070 by going to Start » All Programs » National Instruments » NI-DMM » Documentation » NI Digital Multimeter Help  » Devices  » NI 4070  » DMM Measurements. You'll find this spec in DMM Measurement Defaults. Hope this helps.

 

Happy Holidays!

Sean Ferguson
Application Engineering Specialist | RF and Reconfigurable Test