Unanswered Labview Question

[Lavanya_sri]

Hello All,

I have searched the entire NI forum to get the answer of the following question. But still I couldnot get the answer.

Which of the following only plots data in evenly distributed intervals along the x-axis?  A) Waveform GraphB) Waveform ChartC) XY GraphD) Both A. and B.

E) Both B. and C.

The confusion is whether option A or option D. But I guess the answer is option A, since Waveform Chart can plot a single value which is not evenly distributed

Please verify and give your comments.

[altenbach]

A waveform graph can also plot a single value, just ensure a good point style to actually see it. 😉

[Lavanya_sri]

Hello Labview Champion,

So the answer is Option D?

[jcarmody]

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[...] "evenly distributed intervals along the x-axis" [...] 

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I think this is the key to the answer.  The X axis in a chart is not time unless your program puts data there accordingly.  A chart doesn't care what the time interval is while it's putting the points evenly along the x-axis.

The only way to get unevenly distributed points on a chart is to chart NAN.

[Ben]

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Lavanya_sri wrote:

Hello All,

I have searched the entire NI forum to get the answer of the following question. But still I couldnot get the answer.

Which of the following only plots data in evenly distributed intervals along the x-axis?  A) Waveform GraphB) Waveform ChartC) XY GraphD) Both A. and B.

E) Both B. and C.

The confusion is whether option A or option D. But I guess the answer is option A, since Waveform Chart can plot a single value which is not evenly distributed

Please verify and give your comments.

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The answer is obvious once you realize that the person who wrote that question did NOT know that a chart that has a data type of of "Waveform" would use the "t0" value of the waveform to plot that data (provided "ingnore attribute" is NOT set).

So forget about using a waveform data type and then try to answer the question.

Ben

[RavensFan]

I think the OP is confusing himself with the statement

"since Waveform Chart can plot a single value which is not evenly distributed"

How can you say a single value is not evenly distributed?  You can make the argument that it is evenly distributed.  There is no unevent interval between points.  Or in reality, it is not distributed at all since it is only one point.

In addition, plotting NaN's doesn't make the points unevenly distributed.  NaN is still a point at the same interval as all the other points.  It is just a special value that just happens to not plot a point, but the point is still there.

[smercurio_fc]

If a point falls on a plot and there's no one there to see it, does it still make a point?

[Dennis_Knutson · Accepted solution]

There should be no confusion at all on this question. A chart and a graph have a single dt value that is applied to the entire x axis. A chart and graph can only display evenly distributed data and it does not matter at all if the data is acquired evenly or not.

[Ben]

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Dennis Knutson wrote:
There should be no confusion at all on this question. A chart and a graph have a single dt value that is applied to the entire x axis. A chart and graph can only display evenly distributed data and it does not matter at all if the data is acquired evenly or not.

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For the purpose of this question YES!

But in 95% of my apps (using the Waveform data type since this lets my plot the actual time an update was recieved) ...

Ben