Building Impedance Analyzer using Elvis

[TCU_MECH_ENGR]

Hi All!

I'm doing a senior design project with TCU Engineering and needing some dire help.  I'm building an impedance analyzer that will measure the impedance of a Piezoelectric Wafer Active Sensor (PWAS) over a given set of frequencies.  This impedance analyzer will be performing "sensor diagnostics" and will be incorporated in our final product, which is a structural health monitoring sysem for composite materials.  The final product will have a DAQ (from NI) and a GUI using LabVIEW.  Here are some design considerations:

1) The capacitance of the PWAS under test is 2-3 nF. 

2) Testing impedances over frequency range of 100 Hz to 20 kHz.

3) It's impedance of the PWAS varies from 1M ohm @ 100 Hz to 8.7k ohm @ 20 kHz (taken with an actual impedance analyzer)

4) The code will eventually need to produce the imaginary part of admittance. 

I am needing help constructing the circuit on the Elvis itself.  I have simple knowledge of impedance bridges, but, as my alias says, I am a mechanical and in need of some expert help.  🙂  So, i guess my question is, what does the circuit look like and how do I go about selecting resistor and capacitor values?

I will be installing the NI Elvis LabVIEW program soon and that should be up and running in the next day or so. 

[Brandon_B]

Hello,

Thank you for using NI forums.  There is a lot of great material on our website for using the impedance analyzer on the NI ELVIS board.  A good place to start is at the Impedance
Analyzer section of the NI ELVIS User Manual.  There is also an example that has been created for logging with the NI ELVIS impedance analyzer.  I would start here and then let me know if you have any additional questions.

Regards,

[TCU_MECH_ENGR]

Brandon,

I try opening the Elvis Impedance Analyzer VI by itself independent of the Elvis software and it is missing files and has errors...

Front Panel Errors

Type Definition "IMP States" not found or contains errors 

Block Diagram errors

polarplot.vi is missing

setinstallwindows.vi missing

readDAQsettingsconfigfile.vi missing

I'm somewhat new to LabView but understand connecting the circuit to measure the impedance of the DUT.  

Thanks for all your help 

[kunalpal]

Dear Brandon,

I would like to log the impedance and the phase data with frequency sweep. The ELVIS II+ toolkit only allows measuring the frequency at a single frequency and also does not allow frequency sweep measurements. Can you please provide the fresh link for the example? The current one is not working.

Thanks,

Kunal