coaxial connector to integral connection

[J-Car]

I am an undergrad research asst. looking for equipment for structural analysis, speicifically accelerometers. I currently have SCXI 1314 terminal blocks which accept the separated wires (is called an integral connection?) but most accelerometers have a coaxial output. What do you recommend I do? Is it possible to just cut the end off of a coaxial wire?

Also, are there any other limitationsin in the 1314 or the SCXI 1520 modul that its plugged into that i should be worried about while shopping for an accelerometer?

Thanks

..I'm new to this...

-jake

[Wallace_F]

Hello Jake,

I'm going to address your last question first.  The limitations of the SCXI-1520 and SCXI-1314 with respect to accelerometers is that these modules were really designed to accept strain gage input. At present, it is unclear whether you can actually use accelerometers with this hardware, and I'm researching whether or not this will work.

Regarding cutting off the ends of the coaxial cables; this will have a negative effect on your measurement if the signal you acquiring is a relatively high frequency. So, unless your accelerometer is in an environment where the acceleration is rapidly changing in a periodic manner, it should be okay just to cut off the ends. But, I would recommend trying to find accelerometers with two wire leads before resorting to cutting off the ends of coaxial cables.  

Best wishes,

Wallace F.  

[AnalogKid2DigitalMan]

An option to cutting is to get a BNC to pin or pigtail adapter something like this:

http://www.pomonaelectronics.com/pdf/d3221_100.pdf

[J-Car]

Is it possible to run accelerometers on a SC-2345 Signal Conditioning Connector Block?

[Wallace_F]

Hello Jake,

Yes, you can use the SC-2345 to acquire analog input signals from an accelerometer.  There is a signal conditioning module that is designed specifically for the purpose of acquiring accelerometer signals.  This module is the NI SCC-ACC-01.  If you would like to see how to build this system, you can go to the SCC Advisor on the National Instruments website. 

Best wishes,

Wallace F.

[J-Car]

The modules I currently have with my SC-2345 are the SCC-FT01 and SCC-SG01. Is it possible to use these modules for accelerometers or do I need to purchase the accelerometer-specific module?

Before, you said that the 1314 and 1520 are not compatible with accelerometers. Are there modules that can be used with accelerometers that will go with my SCX1001 Data Acquisition System?


I appreciate your help

-Jake

[preston_johnson]

The choice of signal conditioning really depends on the sensor.  Some accelerometers (the mems type) take a constant voltage and their output is compatible with most data acquisition input.  The more common accelerometers, say from www.pcb.com, require a constant current source.  The NI DSA hardware and the SCC-ACC module referenced above provide this IEPE constant current source excitation.  You will also want to use anti-aliasing low pass filters in your data acquisition system as well.  The SCC-ACC module has a low pass filter.  The SCXI 1530 and 1531 have a low pass filter.  The DSA modules 9233 and 9234 also provide IEPE and low pass filters. 

What accelerometer brand and model are you using?

Message Edited by preston johnson on 06-11-2008 12:10 PM