Keeping the start time axis of waveform chart at t=0 and increasing acquisiton time by shrinking the output waveform?

[ouz]

Hi,

I am a new user of Labview and I try to learn LV by reading books and by looking examples under Labview. Then, I try to write my own LV. I have very simple question although it took lots of my time. I am right now reading a Analog signal continuously and am showing that in Waveform Chart. I want to show the output as this:

X-axis(time axis) starts at t=0 and it remains at that value. As time goes on, highest time(right side of waveform) increases shrinking the waveform. I know that it is possible since I have done previously but I couldn't remember how I can and I have also searched but I couldn't find anything.

Thanks,

Ouz.  

[altenbach]

Several things are important for the x-axis of charts:

Autoscale X: determines if the axis scales to the number of data points or not.

History size: determines the maximum number of points retained in the chart buffer.

Once your data exceeds the chart buffer, the lowest possible x-axis marker will show how many points got dropped.

If you don't autoscale, the number of displayed points is constant (and possibly smaller than the history size). As new data arrives on the right, older data drops off beyond the left boundary.

You also have a choice of update modes.

It seems you want to enable autoscale. In addition, you should be aware that the chart buffer retains data between runs of the program, so you probably want to clear the chart buffer as a first program step.