Question about Multiplot XY Graphs

[hassanaly_nadine@yahoo.fr]

Hello,
A question in connection with my application: TracerCourbeMoteurMAS.vi, I will like in real time to post the various curves according to time,according to choice's of the user by choosing the curves which he would like to post (see Show). I don't know how solve my errors (imcompatibility of the types of data).
Thank you very much for your assistance.
I send my files to you.
Nadine

[Dennis_Knutson]

When you bundle the signal data type with a numeric, you are not creating a valid input for an xy graph. In fact, it's not a valid data type for any type of graph. I've attached one way to select which plot to show by using signal data types. If you want to use waveform data types, then you would could skip the Waveform Array to Dynamic function. If you really need multiple xy plots, then convert each signal to a 1D array and bundle that with another 1D array for your x or time scale. Each one of those would be combined with a build array for a multi-plot xy graph. This I've shown at the bottom of the attachment.

[hassanaly_nadine@yahoo.fr]

Hello,
Thank you very much for your assistance.
I understood the principle but however I do not know because no curve can be plotted in the XY Graphs (see the vi).What is the problem?
Moreover, I do not know if my argument is true but I noted that for for Waveform "Signal out", the color of the signals change (is not fixed), for example if I only notch on Isb, his color is white, however if I choose the curves Isa and Isb, the color of the Isb curve becomes red.How one can fix the color of each curve so that there remains the same one some is the selected number of curves.
I thank you in advance
My best greetings,
Nadine

[Dennis_Knutson]

If you want to use the XY graph, then you have to create an array for the x values. In the example I posted, the array is empty because I don't know what values you want. I'm also not sure that you really need an XY graph but that's up to you.

If you want each signal to always have a specific color, then you'll have to add some code to assign that color. By default, each signal will use the color you've assinged in the graph's plot legend. It does not do this by name but in the order that each plot is in the array. So, for example, if you have Isb and Irc plotted, they will have the names and colors of the first two plots in the legend. You can use a property node to change these to match the name of the signal and assign whatever color you want. I would suggest you create a couple of array constants. One has the signal names and the other has the colors. Use the for loop where you process the boolean array to index the name and color array to match everything up.

[hassanaly_nadine@yahoo.fr]

Hello,
Thank you very much for your assistance,
I tried to modify my VI according to your council but I did not succeed in fixing the colors of each one of my curves.
Will be able you to throw a glance in my VI Select Plot.vi
I thank you in advance, Nadine

[tca-adam]

Is is possible to save the Select Plots.vi example on V6.1 format?

I am trying to do a multiplot XY graph with a non linear timebase.

thanks

Adam

[Philip_Courtois]

Hi Adam,

There are features in the "Select Plots.vi" that are not supported by LabVIEW 6.1, so I created a small example that shows the same kind of functionality in LabVIEW 6.1.

Hope you can use it.

Have Fun!

Message Edited by Philip C. on 05-09-2005 07:31 PM

[tca-adam]

Ahhh the number of different ways of doing things as a new LabView user is all rather daunting!!

But it is exciting to learn new concepts....

Does this 'waveform' data technique allow for a changing sample times/time base?

my scenario is I want to take temperature measurements every 5 minutes and graph 10 selected channels out of 100 channels (Note: this selection of 10 needs to be able to be changed during the recording). As well as these 5 minute regular scans, the user must be able to 'force' a scan whenever they want, that will also be displayed on the graph, resetting the next sample time to five minutes later.

thanks
Adam

[tca-adam]

I would love some feedback on what people think is the best storage method for this sort of multiplot data

eg 100 channels scanned when the user pushes a button. ie a non regular timebase.

[Philip_Courtois]

Hi tca-adam,

Interesting question, you might get a lot of different answers to this one.

The most important question is how you want to retrieve the data:

• Will you always read the file from LabVIEW or do you want to read it from a non LabVIEW application?
• Do you want to be able to read it in Microsoft Excel (spreadsheet)?
• Does the size of the file matter?

If you only want to access the data in LabVIEW and you want the file to be small you should start by looking at the shipping examples called "Write Datalog File Example.vi" and "Read Datalog File Example.vi". "Datalog" gives you the option of storing data as your own customized slice. One slice could be a Waveform of 100 samples and additional information like the name of the channels acquired, who was performing the logging, and the ambient temperature (these were all made up). You complete file will then store multiple slices of this type, and you can retrieve them one by one.

If you want to asses the data in for example Microsoft Excel, you have to save the data as ASCII (text). See the Spreadsheet examples for this approach.