Multifunction DAQ

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data acquisition for vibration monitoring

hello every one!
i am an undergrad students and are building a vibration monitoring system for my final project. I've finished building the software with labview, and now it's time to put it into test.

This is where i need help from you guys.

i'm planing to test it with a compressor. we have bought NI 4472 DAQ and 100mV/g accelerometer. the distance between the computer and the accelerometer is about 30 meters. Now, the problem is, since the acceloremeter cables is just 5 meters only, how can i extend it so i can have a good reading? what are the cable spec needed? cause this is my first time with real measurement signal, what are the things that i need to take caution of?


this is from the accelerometer datasheet:
Cable: Integral cable 5 meters (16 feet) long.
Shielded twisted pair; 2 times AWG 20. Shield
grounded to sensor housing. Cable armored
with stainless steel braid. Braid also connected
to sensor housing. High temperature cable.
Cable diameter less than 5mm (0.19").
Cable Specifications: 2/C 20 AWG FEP/A/M/FEP
10-1254. Recommend two (2) wire, twisted,
shielded.

any help is much appreciated
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Message 1 of 6
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Hello,

For future references, the correct place to post questions about the NI 4472 is the Dynamic Signal Acquisition (DSA) board, not the Multifunction DAQ board.

One of our DSA systems engineers ran some tests using a 100-ft RG-62 cable (like this one) to provide sensor connectivity to a DSA device and had no problems with signal degradation.  I would recommend this cable for your application.  Let me know if you have any questions about this.

As far as general information on what you need to take into consideration when measuring analog signals, check out Field Wiring and Noise Considerations for Analog Signals.  I'm not sure if this is what you were looking for, so let me know if you need to know something more specific.

I hope this helps!

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ow! ok, thanks alot for the guidance, and sorry for the misplaced post. i'll try the cable once i get the opportunity.

thank you once again, much appreciated
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No need to apologize for posting to the wrong board!  I just wanted to let you know for next time because you will be more likely to get help from people who are experts on your hardware if you post on the correct board. Smiley Happy
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Hello there, after a research, i found out that (correct me if i'm wrong) an RG-62 is a single wire 22 AWG coax cable. But, like i stated before, the sensor reccomends 20 AWG two wire twisted shielded. won't there be any problem?

thanks for your help!
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Hello,

I doubt there will be any problems just because it is not the exact cable recommended by the manufacturer.  I recommended it because it worked well in tests conducted with our DSA devices.  I don't know of a specific cable with those exact specifications (20 AWG, twisted pair) and I think the RG-62 is similar enough that it really won't make a difference.

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