USB 4431

[kamn56]

Hello,

I would like to measure vibration in the range of 5-500Hz. Can I use USB 4431 with the appropriate sensors.

Thanks

[mcduff]

You could use it with some work. 

I would suggest that you Google the specs of the 4431. If you do so, you will find that the minimum sampling rate is 1000 Sa/s. So you will need to do some data processing with the acquired signal to have a rate between 5 - 500 Sa/s. You can take the mean, median, max, min, etc.

mcduff 

[kamn56]

Dear mcduff,

First of all I need to tell you that I am not an electrical person. So my understanding of electrical instruments is very minimum. 

1. If I used sampling rate greater than 1000Sa/s, do I still need to do post-processing on the signal of 5-500Sa/s? I have been using DAQ 6289, and there was no post-processing required.

2. Is this USB 4431 compatible with geophones adapted with BNC connectors?

3. How do I protect the USB 4431 in areas of heavy electrical interference/noise? Is there a way to ground the equipment?

4. Is it possible that I try out the USB 4431 with my geophone before I decide to purchase it for my personnel research related to measurement of vibration in the ground?

Regards

[mcduff]

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@kamn56 wrote:

1. If I used sampling rate greater than 1000Sa/s, do I still need to do post-processing on the signal of 5-500Sa/s? I have been using DAQ 6289, and there was no post-processing required.

Not sure I understand your question. The minimum sampling rate for the 4431 is 1000 Samples/s; if you want less than 1000 samples per second, you will need to do post processing. If the extra data doesn't bother you then you don't need to do anything.

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@kamn56 wrote:

2. Is this USB 4431 compatible with geophones adapted with BNC connectors?

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I have no idea. The 4431 is an IEPE enabled 24 bit digitizer. The 4431 can output ~2 mA of DC current to excite an IEPE sensor. I know nothing about your geophone.

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@kamn56 wrote:

3. How do I protect the USB 4431 in areas of heavy electrical interference/noise? Is there a way to ground the equipment?

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There is a grounding pin in the back. Shielding and grounding is site specific, so I cannot answer your question.

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@kamn56 wrote:

4. Is it possible that I try out the USB 4431 with my geophone before I decide to purchase it for my personnel research related to measurement of vibration in the ground?

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You can talk to your NI Rep.

mcduff

[kamn56]

Thank you

[zhm0204]

Hi mcduff ,

May 4431 work with a external sampling clock?

Or is there a USB multifunction card that have a 24 bit resolution and may work with external sampling clock?

Best Regards. Have a nice day.

Zhang ming 

[mcduff]

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@zhm0204 wrote:

Hi mcduff ,

May 4431 work with a external sampling clock?

Or is there a USB multifunction card that have a 24 bit resolution and may work with external sampling clock?

Best Regards. Have a nice day.

Zhang ming 

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Some USB cards have PFI inputs that allow one to use an external sampling clock. The 4431 has PFI inputs in the back on the 9 pin connector; no idea if they support an input for an external clock. As far as other cards goes, the NI website has all the information; I do not know of any model offhand.

[santo_13]

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@zhm0204 wrote:

Hi mcduff ,

May 4431 work with a external sampling clock?

Or is there a USB multifunction card that have a 24 bit resolution and may work with external sampling clock?

Best Regards. Have a nice day.

Zhang ming 

---

Unfortunately, No, Delta-Sigma modulators in DSA cards cannot take an external sampling clock as the clock has to be continuously running in order to work.

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019OVZSA2&l=en-US

https://www.ni.com/en-us/innovations/white-papers/10/benefits-of-delta-sigma-analog-to-digital-conve...