Digital Inputs do not record over long time periods

[JoeyG]

I am running Signals Express 2009 with a USB-6009.  I have a project that needs to record the states of 8 digital inputs over a 24 hour period.  The inputs typically do not change state for long periods of time.  When I run the project it does record and gather data if I stop it "soon"(I have gone as long as 30 min.)  When I leave it running overnight it does not appear to record anything.

[EadieU]

Have you tried setting it to Record while Running? This should create a log file while you're running, so you shouldn't have this problem of it not recording data.

I recommend looking at the section titled "Logging while Running"in the Data Logging - LabVIEW SignalExpress 2009 Help

[JoeyG]

Mark,

I do have it recording and it does record for a short period of time.  I have attached the project.

Regards,

Joey

[JoeyG]

Mark,

I don't know if it means anything but look at the attached screen capture of the record screen for the estimated log size and the recording time available.

Regards,

Joey

[EadieU]

Joey,

Thanks for the project file and the screenshot.  I've been able to successfully record for less than 30 minutes with your project file - it's still running. 

As for the screenshot, do you always see that very large negative value for the Current estimated log size? I saw that in your project when I first ran it, but it does not show that anymore.  

Also, have you tried a new project file?  Sometimes the new file won't have the same problem. 

[JoeyG]

Mark,

I should clarify - It does record but there appears to be nothing there when I playback.  7 inputs are high and occasionally go low and one is always low. 

The large negative number is always there.  When I created a new file it went away but came back after a few runs.

I purchased and installed a duplicate setup to monitor another site and I seem to have similar issues on a different PC.

Regards,

Joey

[JoeyG]

Mark,

More information - The I saved a text file which appears to have transitions in it.  Perhaps this is a playback issue? 

Regards,

Joey

[EadieU]

If you have not already, you should try turning off display updates in the "Operate »Update Signal Views While Running" menu item.  Set this to Update None.  Also, turn off "Prepare log data for viewing" under the Logging part in the Tools » Options dialog.  

When I ran your project overnight, it ran out of memory.  The first error it threw was "Not enough memory to complete this operation."  The problem was that SignalExpress saved a great deal of data in memory for easy displaying while it's running, but this grows too big when it runs overnight.  The second error was as follows:

Logging Stopped:

Logging was stopped because an error occurred with a Step in the Project. 

If this error is because of a device buffer overflow, you can improve performance by turning off display updates using the "Operate »Update Signal Views While Running" menu item.

You can also change the way signals are logged by changing the Logging Options in the Tools»Options dialog.  

Turning off  the "Prepare log data for viewing" will greatly improve performance.