Impedance and Phase Angle Outputs with Keysight 4294A

[LRubin1006]

Hello,

I am using LabView to run my Keysight 4294A Impedance Analyzer.  I have been able to get the program to initialize and set up all of the parameters and take the compensation date from the open and short of my 16047D test fixture.  After I affix my DUT into the leads the program will continue formating the graphs and autoscaling them.  When I use the Read Data and Memory Arrays to output the data to waveform graphs and a table, the |Z| (impedance) data is displayed correcty but I have not been able to get it to output the theta (phase angle) data to show up correctly on the graph or the table.  I have tried switching active traces and using multiple read functions but so far I can not get it to work.

Does anyone know how to get this to work?

Thankyou all,

Logan

[thuyanhl]

Hi Logan,

When you say it is not shown correctly, do you mean it is not displayed at all? 

Best Regards,

[LRubin1006]

The Impedance is displayed correctly but the phase angle is not.  I am not too sure which module to use to display the phase angle or what units LabView would output this number.  On the instrument it will show a phase angle near zero until about 1MHz and then it will go very negative and the data that I am getting from the secondary output from the read array module is not that at all.

[thuyanhl]

Hi Logan,

From the Agilent 4294A manual, it seems like Trace B should reflect the impedance phase. Could you post a picture of the two waveforms you are getting in LabVIEW? Are you getting the correct data? If so, you can always use the “Extract Single Tone Information VI” in order to get the phase of the two signals. 

Also when you say the data is different from the one you are getting from the scope, does that mean the values are just random? Could you also show the data of the table after you run your code?

Thanks,

[LRubin1006]

Hello,

I have attached an excel data sheet showing the numbers that I am getting from my LabView program as well as a snip of the block diagram I am using and the front panel and a photo that I took with my work phone of the scope on the actual meter.  You will see that the impedence graph correlates directly to trace A (yello) and the numbers are correct.  The phase angle in degrees graph should be the same as trace B (blue) but clearly it is not.  I took the output data as it was in radians and converted it to degrees but even when it was in its original form the graphs and data look nothing like what I am getting on the scope.

Let me know if you see anything I messed up on or have any advice as how to get the phase angle data and graph to be correct.

Thanks,

Logan

[LRubin1006]

Here is the image of the scope as it would only let me attach 3 attachments.

[thuyanhl]

Hi,

Thank you for attaching all of yours files. Have you tried different formats for configuring the display of your trace B? What do you get when you select "Complex Plane"? 

Thanks,

[LRubin1006]

T. Le,

I am getting an error message when I select "Complex Plane as the formating for trace B.  I guess where we are really confused is what is the secondary output from the read data VI.  I have figured out the primary output is the Impedance and assumed the secondary was the phase angle but maybe that is wrong.  Do you know what the secondary output of this VI is?

I have also attached a screen capture of the error.

Logan

[LRubin1006 · Accepted solution]

T. Le,

I was able to figure out with comparison to another instruments measurements that the secondary output was the imaginary impedance and from there calculate the phase angle using the arctan of the imaginary over primary.  I appreciate you responding to my problem and I hope this thread can help anyone that encounters the same problem.

Logan