IEPE Triaxial Accelerometer Issues with NI 9234 Module

[cjwarren]

Hello NI Community,

I am attempting to connect an Omega ACC 301A triaxial accelerometer with an NI 9234 DAQ module. This accelerometer uses a four pin connector, so I am using a 4 pin connector to 3 BNC terminal cable to connect to the 9234 module. On the spec sheet for the Omega ACC 301A, it states an excitation current of 2 - 6mA @ 15 to 30 VDC, which is in the range of my NI 9234 card and an amplitude range of +/-5 V, which is also in the range of the NI 9234. 

In the DAQ assistant, I have all constants set per the accelerometer spec sheet, but when I run the VI, the X axis does not respond to any motion, and the Y and Z axes seem to drift when the accelerometer is motionless. I have attached my VI to this post as well as a screenshot showing a real time plot of data. In the screenshot, the triaxial accelerometer is motionless yet has an almost sinusoidal curve present between -.1 Gs to 0 Gs. 

Does anyone know what might be causing this drift on the accelerometers voltage output? Also any reason why the X axis wouldn't respond? This is a brand new accelerometer that was calibrated within the last month.

I have used this same NI 9234 card with other IEPE triaxial accelerometers with no issues. Any advice would be greatly appreciated!

Thanks,

Chris

[Cooking_Up_Code]

I've started the conversation to this question over on the signal conditioning boards. The link for which can be found here.

http://forums.ni.com/t5/Signal-Conditioning/IEPE-Triaxial-Accelerometer-Issues-with-NI-9234-Module/m...

[ugo2018]

Does anyone know how i can connect the NI9234 to the Endevco model 2220E accelerometer. the challenge is, the endevco uses an in-line charge converter however the NI 9234 does not require this. any suggestions will be appreciated. 

thanks 

Ruq.

[Henrik_Volkers]

The Endevco model 2220E accelerometer has a charge output. (SI Unit pC/(m/s²)) . The in-line charge converter converts the charge output to an IEPE ( ICP/CCLD/..) output (V with about 12V bias while the supply current is provided)  that the NI9234 can read (while providing that current)

So, to correctly connect the sensor to the 9234 you need a seperate charge-amplifier with own supply and a voltage output or that converter.

[ugo2018]

thanks a lot