Graph Waveform Arrays

[Maj]

Hi,

I want to have the Graph of an array of measurments. I measure the power loss in channels A and B as an SWR value.

This value changes as I change the frequency externally.

how can I have thegraph of the whole range of measurements, could I give an array list of frequencies for input ?

please if any there 're any ideas...

[Fox_Mccloud]

Hello Maj.

Do you want to plot different measurments in the same graph? If that is the case take a look at the vi attached.

If this is not the case. Could you please refrase the question?

Cheers

//Beckman

[Maj]

Hi,

unfortunately I can open the file you sent me, because my LabVIEW version is older 7.

The device I control through Labview changes the  values with frequency.

I just want to build a graph of those values, for the time being I just have one value of a percise Freq and I dont know how I could

make I graph.

I need to give a list of the frequencies and take the result graph of power changes.Could it be possible?

[DanielHermyt]

Hello Maj,

1. You can write your frequencies to a text-file and then read it in to LabVIEW by using "Open/Create/Replace File", "Scan From File" or "Read File",  and "Close File". There are some other functions on your File I/O-palette that you can use.

2. There are some possibilites to view your data on a graph. You can read every single value from your instrument and write it to a file using e.g. "VISA Read To File" or something else from the Instrument I/O-palette. Then you can read the file (-> 1.) an display the data on a graph. Another possibility would be to read the data (e.g. "VISA read") and writing the data to an array wich you display on a graph. Using the XY-Graph requires specific data for the x- and y-axis that you can combine in a cluster and direct to an XY-Graph.

3. If your instrument can be controlled via GPIB, I suppose it will be possible to create a LabVIEW program wich solves your problem. Although I don't know your instrument, I'm quite sure there will be commands to set the frequencies numerically or a range of frequencies with a measurement distance. There can be possibilites to read all the measurement results at the end of all measurements and display them on a graph. Many manufacturers provide LabVIEW-Instrument-Drivers for there instruments. Perhaps you can get them for your instrument and LabVIEW-version.
If this can be a possibility for you, please let me know wich instruments you are using and how you realize the connection between the instrument and your computer.

I hope I could help you with my comments. If there are further questions, don't hesitate to post them.

[Maj]

Thank you very much, your instructions were really helpfull.

I do have the drivers and I have done a GPIB connection with my device which is NRVD_857.8008.02

with the VI I use now I can only get the measurement value in each  frequency I switch in. I would now want to try making  a list of the values measured in a range of frequencies and draw the Graph of the measured object behavior.

[DanielHermyt]

Hello Maj,

there should be an example coming with your LabVIEW-distribution called "Write to text file.vi" that gives an example how to write data to a file.
You can use the function "concatenate strings" to bring arrays of string together to one string that can be written to a text file. There is also a possibility to set the position for writing at the end of the file. This gives you the possibility to write measurement per measurement to the file as a set of frequency and SWR. After that it is no problem to view the data with LabVIEW or if you like any other program like Microsoft Excel.

I hope I understood your needs correctly and could give you some useful hints.