Add markers on Chart while measuring

[obr3ptox]

Hello everybody.

I am working on an interface for a GSR (Galvanic Skin Response) measuring system in Labview 13.0 .

I am acquiring data through a COM port, elaborating and plotting it into a chart.
I need a method to add markers (bookmarks) on the chart by pressing a button, in realtime.

For example:

Acquisition is started and proceeding;

The patient is asked to jump;

A button is pushed and a marker is added to the chart in that instant;

Acquisition goes on;

The patient is asked to relax;

Another button is pushed and a marker is added to the chart in that instant;

So on.

Could you please give me a help?

[GerdW]

Hi obr,

you are rather limited with charts! Your best option then is to use an additional plot which uses an arbitrary value as marker and NaN otherwise…

You get more options when you use graphs instead: the support cursors, annotations, front/middle/background images…

[obr3ptox]

So you suggest me to perform the "chart to graph" conversion and operate on it?

How could I do what I need in that case? I mean the realtime annotation.

[GerdW]

Hi obr,

LabVIEW comes with a lot of example VIs in the example finder.

There are also examples explaining how to use cursors and annotations. Did you check them?

When an event occurs you create an annotation or a cursor…

Again: the most easiest way would be to use an additional plot, set to hide lines and show only points…

[obr3ptox]

Thank you for your answers.

I proceeded in converting my data to be plotted on a graph (so that the cursor and annotation can be used).

Nevertheless, my problem is still there: I would like to associate a "key pressed" to an annotation on the graph at the instant I pressed the button.

I'd be glad if someone could help me with this.

[PalanivelThiruvenkadam]

Try something by your own based on the infomation providex and share the one which you have tried and we can help you from there if you are stuck.

[GerdW]

Hi obr,

to detect/handle keypress events you can/should use an event structure!