visual display of x hours of data

[fredericb]

Dear all,

I was wondering if it is possible to display say 24 hours of data without saving it to create html report daily. At the moment i can't even get 10 min as the previous data is erased automatically. i've noticed that by changing the dt on the waveform i can increase the timebut lose a few data if they happen too fast. I dont required the data stored as i just want to display them.

Is there a way to do so?

Thank you in advance for your reply,

Frederic.

[JÞB]

Well you have to store them somewhere if you want to display them.  I assume you are using a chart?  make the charts history lenght = the number of points taken in 24 hrs and the chart history becomes a nice rolling buffer of the correct length

[fredericb]

Hi Jeff,

thanks for the reply. yes i'm using a chart and i'm already controlling the chart history the way you describe. Let's say the first 5min of data that are on my graph is it possible to keep it on display without it being erased by the next 5min? for example i start my acquisition at 12:00:00 at 12:05:00 it's erased and it starts again till 12:10:00 and so on. So let's say my x axis cover from 12:00:00 to say 15:00:00 if i run my VI for that 3 hour period i will only see the data from 14:55:00 to 15:00:00 and the rest of the chart is blank. My point is: since at some point the data has been there and displayed is there a way to tell labview that 5 minute of chart is an image kind of thing instead of data and add to it as the chart goes along that way i could display the full 3 hours on one chart storing only the last 5 minutes?

Fred

[fredericb]

To add to my last comment: When you do html report it is possible to save your chart as an image. Say your charts have clear background it should be possilbe to mount multiple images of 5 min of data as one image of 3 hourshard work i know but that would save a lot of disc space (5 min of my data is around 16MB vs an image of 5 min of data is around 17KB). Saying that i don't know how to do so without using html report. Is there a way to save a chart every 5 min as an image?

[JÞB]

Yes.

Set the correct update mode (you want a strip chart) and history length

Then create an invoke node on the BD-  Pick from several formats to export the data in! and use a timer to call the invoke method periodically.

[fredericb]

Hi Jeff, 

Thanks for the tip. I'm using "get image" instead it's working good.

Thank you for your help.

Frederic.