graph or chart with time date

[johnjt]

Hi Dennis, 

Yes, I guess I shouldn't say it's a memory leak, but when the memory use goes from 100k to 1 gig, it sure looks like one.

Were you referring to the Chart Buffier vi that is in that example?  I just now tried to use it but it seems to not like my double array or even the graph data cluster as inputs.  Also, it appears to be related to chart history lenght, which I have set to 1k and would assume it would perform the same way, throwing out unused data?

Is there a way to reset an array to zero elements and start writing to it again?  I've never seen that done.

Why is this so DIFFICULT to do in Labview?  I can easily get the year 1903 or 1904 but those were pretty crummy years!

Thanks again for all your help.

John

[Dennis_Knutson]

Sorry, but I did not even look at your VI. I just responded to a problem with a build array and forgot that my example was not using an XY Graph.

You really do not need the build array in your example. Since you are using a chart and it is regulary sampled, you just need to correctly set the x axis. The example you want to look at is called Real Time Chart. 

Charts and Grapsh do not automatically get the current date and time. It is something that you have to provide. In the earlier example, this is done with using the waveform data type. If you don't want to use that, then writing to the chart's property nodes like in the Real time Chart example is the way to go.

[johnjt]

Not to be a pest, but I did look into the Real Time Chart example, but still could not find a way to get the date.  You can get the time.  However, I'm not sure how to get the DATE.  The unbundle by name for the time, does have day, month, year pulldowns, but I'm not sure how to incorporate that into the chart?

[Dennis_Knutson]

You just convert the timestamp to DBL and wire that to the XScale.Offset. Change the formatting of the x scale of the chart to show absolute time. Right click on the chart, select X Scale>Formatting. You may have to change to default editing mode. then select either Cutom date format or System date format.

[johnjt]

Dennis, you are a genius!  That did the trick, again.  Thanks for your help.

[johnjt]

For those of you wondering, here is the modified Real Time chart example with date.  LV ver 8.