How to display accurate elapsed time on waveform chart/graph

[pj1390]

Hello,

I have recently been doing small demos on virtual data to get ready for when I use actual data. In this test VI I created a sine waveform that creates a new sample every 100 ms in a while loop. I have scaled the function simply to make it larger. My goal was to be able to display this waveform on both a chart and graph, and I was successful but I can't figure out how to get the x-axes of both the chart and graph to show actual elapsed time in seconds.

I have tried to edit the advanced options in the chart/graph properties and fiddled around with sending clusters into the graph but I can't seem to get it to work. I really don't know what the x-axis is displaying and don't know how to control it.

I have attached my simple VI. Any help would be much appreciated. 

Thank you.

[moderator1983]

Can you save your VI in version 2012 and re-post it.

[pj1390]

Sure.

[RavensFan]

The waveform graph's X scale has a default offset of zero, and a default Multiplier of 1.  Since you are sending data to it 10 times per second, you need to set the Multiplier to 0.1.

Then you need to set the display a time format that displays seconds, rather than just hours:minutes like you do now.

[pj1390]

Awesome that worked! So the default multipler of 1 means that it assumes 1 sample/second?

[moderator1983]

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@pj1390 wrote:

Hello,

I have recently been doing small demos on virtual data to get ready for when I use actual data. In this test VI I created a sine waveform that creates a new sample every 100 ms in a while loop. I have scaled the function simply to make it larger. My goal was to be able to display this waveform on both a chart and graph, and I was successful but I can't figure out how to get the x-axes of both the chart and graph to show actual elapsed time in seconds.

I have tried to edit the advanced options in the chart/graph properties and fiddled around with sending clusters into the graph but I can't seem to get it to work. I really don't know what the x-axis is displaying and don't know how to control it.

I have attached my simple VI. Any help would be much appreciated. 

Thank you.

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Though the delay in the loop is 100ms, it is not very accurate (as your code is running on Windows and not on a Real-time OS) so in order to display the time veryaccurately, you need to use XY graph.

Attached is the example.

[pj1390]

That's a very neat solution and gets around the delay issues that I have had.

Thank you!

[RavensFan]

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@pj1390 wrote:

Awesome that worked! So the default multipler of 1 means that it assumes 1 sample/second?

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Actually, it means 1 second per sample.