L O N G graph displays?


MDVolle

Recommended Posts

This may be a really rookie error or oversight but I did have it working once and can't seem to do it again...

I have data coming in from a Labjack U12 at 20/sec times four channels - I have history set to 72000 and persistence set to 3800000 - This should, in theory be about two days?

I have several short time frame graphs using the same data and they all work fine - up to a time length of 600

My graph that is intended to show a full two days doesn't work - I can't get a display longer than a time length of about 3600 - 

This makes me think I am missing something completely - if I set the time length to 200000 I get a display with two + days and dates shown in the graph window - at this sampling rate, I thought that the window (time) length would also be 3800000?

Is time window length independent of sampling rate? 

I am clearly missing something about the process and previously (on a com-user where I was lucky to sample at 1/sec) got everything to work

What Have I failed to understand?

 

Thanks

Mark

 

 

 

Link to comment
Share on other sites

3600 at 20/sec is 72000, so basically you are just seeing the history.  To access persist data you must subset.  This is to prevent you from accidentally pulling a huge chunk of data into RAM.  For a graph, the best way to subset is to use the bottom axis scaling, which is available as a variable.  So if your Y axis expression is "MyChannel", you would change it to:

MyChannel[bottomAxis.currentScaleFrom, bottomAxis.currentScaleTo]

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.