Frequency sweep measurement using HP4194 A analyser

[PierreD]

Hi all,

I'm a new user of Labview and I have some troubles to create a working VI.

The idea of my measurement is to perform a frequency sweep, measure the impedance and plot the result from a 4194A analyser and Labview

Currently, I can configure the frequency sweep (start, stop and step) and I can plot my result.

However, I have a problem regarding the last part.

Indeed, when I perform a single scan, the analyser start to make continuously measurment and not just 1 scan. Furthermore, when I realize this scan, my plot is not fully updated.

I think I have to put a loop or a timer but I don't know where and how exactly, I read tutorials but I don't understand how to do.

I attach the VI.

So, how can I do the perform a complete scan on my analyser, wait that the scan is finished and then plot (and save) the datas?

I thank you by advance or your help

Pierre

[Janselm]

Pierre,

I don't have this particular piece of equipment but I installed the drivers for it and it looks like if you add "Agilent 4194.lvlib:Sweep Type.vi" you can change the sweep type from repeat to single. This should prevent the Analyzer from entering continuous sweep mode. I would also recommend adding the initialize.vi from the instrument drivers to open the VISA connection, query, and reset the device (if desired).

This may fix the plotting issue as well since it is receiving data from more than a single sweep.

[PierreD]

Hi Janselm,

Thank you for your response.

I based my work on this library, but it seems that I miss this information.

I add the sweep type block and also the initialize block (such as their example).

I also add a timer between my "sweep trigger" and "display mode" of 25s. So I will wait 25s to plot the graph.

But it doesn't seems to be perfect.

And do you know what means "Improper delimiter" ? Is there a problem with my selected parameters ?

[Janselm]

Pierre,

It makes sense if the program is reading the data before it is done sweeping that you would need a delay. A lot of instruments I've worked with have a node that will wait until sweep is complete before reading measurements or a node that will read the sweep time that you can wire into a delay node. I don't see either of those

When and where are you getting the "Improper delimiter". I don't see anything on your block diagram that requires a delimiter. Can you step through the program or use execution highlighting to see when and where this error is occurring?

Regards, Jay

[PierreD]

Jay,

Thank you for your response,

Regarding the improper delimiter. I have this message (with a bip sound) on the screen of the analyser when I start a measurement. On Labview, I don't have any message or error.

I will use the higlight tomorrow and come back to you asap.

Thank you for your time,

best,

Pierre