How to display a waveform in XY format where X is the time in seconds?

[RPJ]

I am aquiring voltage from a power sensor and I am displaying this voltage as a waveform in a waveform chart. Now, I would like to display this waveform such that on X axis I have a range from 0 to 30 seconds (X axis should be displayed in seconds of recording not actual time). On Y axis I would have the value of parameter I am aquiring of course.

Any suggestions/examples?

[Dennis_Knutson]

Look at the shipping example called Real-Time Chart. This sets the actual time on the x axis but if you want it to start at 0, just write a zero to the XScale.Offset. To set the range to 30, write 30 to the Xscale.Maximum.

[RPJ]

Thank you.

This looks a little cumbersome. Would there be other solutions maybe simpler?....

[Dennis_Knutson]

What exactly do you find cumbersome? What kind of data are you acquiring? Is it a waveform data type or signal type that has timing information embedded in it?

[RPJ]

It is a data signal type that has timing info in it.

What I am actually trying to achieve is to display the data in a chart (that has seconds on X axis) only when I turn on a button. When I turn off the button the data should stop being displayed in the chart. Problem is that when I turn on the button again the new data displayed should flow from the point where old data stopped being displayed. In a chart having actual time on X axis this is not possible because the time will be different that the time when the data stopped being displayed so you will have a gap between the old and new trains of data. I want continuity and I was hoping to get this if I take the timing info out...

Do you see a better solution for this?

Thank you.

[Dennis_Knutson]

You can remove the time information if you want. Here's a modification of the Real-Time Chart example. I used the DAq Assistant for two channels and on-demand sampling.

[RPJ]

Thank you.

I'll have to try it next week. I'll be out "in the field" by that time...

Radu

[unclebump]

What you are asking for is not possible with a chart. You want to make the Xscale so that it is not linear by hiding datapoints between certain timeframes. This can't be displayed on a linear axis. Basically you want a scrolling tape that can be halted and restarted where it left off.

[RPJ]

Something like that...

[unclebump]

Maybe this will give you some ideas.

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B123AE0CBAAC111EE034080020E74861