Absolute Time Chart, Change x-axis

[charmand79]

Hi all,

I have a problem with changing the x-axis in an absolute time chart. The chart has been built following the instructions provided by NI here: https://decibel.ni.com/content/docs/DOC-8097 On first look one would say that it works fine.. However, when you try to change the x-axis so that you can display a different time window (e.g. xmin, xmax is at 15:00:00, 15:20:00 and you want to get it to 15:00:00, 15:40:00) while the VI is running you get all sorts of nonsense. Usually, what happens is that the plot "reverses" so that you xmin is actually later than you xmax!!

Any suggestions?

PS. I am running LV2011

Regards,

Harry

[RobCole]

You can set your x scale to the number of minutes that you want. Say 00:00:00 to 00:20:00 and then set the x-offset property to be your start time. Setting it to 15:00:00 will give you a scale from 15:00:00 to 15:20:00 (to use your example). Then if you want to show a larger scale, just change your x max at run time (say to 00:40:00).

I suspect that, in the background, this is how LabVIEW does it. When you change x max programatically, it subtracts x min - so you get 00:40:00 as x max and since x min is 15:00:00,  you are now counting backwards.

The offset method works quite well.

Rob

[Rasoul]

Hello every body,

Actually I have been confused by the unit of X scale of a waveform chart. if you look at the picture below, you will see that the X axis scale for  minimum and muximum , there are two sientific numbers , I could not figure out how to calculate the disered time that is needed to display on the graph. So : please first what are the units of these numbers, how can I set the interval for exapmle  10 minutes, I should be notice that I am using absolute time format...

[RavensFan]

That is seconds since January 1, 1904.  (roughly)

[Rasoul]

Thank you so much for your reply. ok. so if I want to specify an interval of time to be displayed, I have to calculate in secound and add it to the maximum value, am i right?

I am asking this question because when I am exporting the displayed data on the waveform chart, just a certain period of time is being exported....

I read in the forum that this is because of my time interval, and I have to extend it to the disired period.... really I do not know  what to do , Please guide me... thanks in advance for your support...