Need help on plotting graph

[Dejun]

I will use waveform graph/chart to plot the change of data with time.

I don't want to use the default x-axis of the graph. What I want to use for x-axis is the time passed, starting with zero.

My code structure is:

In a loop structure, I read one force from DAQmx read (I extracted the DBL data from waveform data), also I got a current time value (the passed time w.r.t. zero  time).

So, in every execution of loop structure, I got a DBL force data and a DBL time. Then I want to plot them to a force-time graph.

My question is: how can I make x-axis to be the time passed with zero as origin?

Thanks. 

[BEHajder]

I think you should try using an XY Graph instead of a Waveform Chart or Waveform Graph...

[Dennis_Knutson]

You can just wire the waveform data directly to the graph. There is no need to extract the the Y array or the current time. To display time on the x-axis, right click and choose X Scale>Formatting or select properties and select the Format and Precision tab. Choose Absolute time and pick the time format you want.

[Sima]

If you wanted to build your own time scale, you could do something like this... (attached)

[Dejun]

Great, I think I should use XY plot.

Another question. I don't want to let the x-axis changes with adding plotting point. To make the x-axis fixed, with zero as starting point and the largest possible time as ending point, I shall use property node of graph, right?  So that I can use a control to set the maximum x value.

Thank you for your patience to a newbie's question.

Derek

[Sima]

Hmm, the example I wrote earlier does that. The start time on the graph is 0, and the end time is whatever the last time is. Did I not get your question?

[Dejun]

Yes, the code you give me can show the last time, but during the plot the x-axis changes continuously.

I just want set the whole range of x-axis fixed at the begining, and the the plot will grows without scaling.

Message Edited by Dejun on 01-23-2006 02:01 PM

[Sima]

I see. You can right-click on the graph to remove auto-scale. To fix the min/max, either from the graph properties under 'scales', or as you said, using property nodes if you need to.

[Dejun]

Thank you so much, Sima.

[Sima]

No problem