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Signal Express logging issues

I am having trouble with the Signal Express advanced logging features. For example, logging will not start at a specified Date/time. I also don't understand the interval logging. If I specify the log to start every 25 seconds and then specify a stop condition of a duration of 5 seconds, I expect the software to log every 25 seconds for 5 seconds. Instead, the logs start immediately for 5 seconds (as I would expect), but then log 2 starts 30 seconds after log 1. Log 3 starts 55 seconds after log 2, log 4 starts 80 seconds after log 3, etc.

Any input would be appreciated. 

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Could you attach your project so we can take a look at it?
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Thanks for your interest. Here is an example 3.0 project which is set up to log 5X at intervals of 25 seconds for 5 seconds. If I then change the start time from immediately to some future time, it never starts. Another odd thing is if I go to the logging window in the options dialog box and change the prepare data for viewing to "after completed" the program hangs and I need to force quit. However, I did see some chatter about that bug in the knowledge base. My eventual goal is to run a 24/7 life test for months. I wanted to break up the data into segments (perhaps every 24 hours) to protect the data in event of a crash. I found I could do this by having no start conditions and have a stop condition of duration>24 hours. I would then set the restart box to how many times (days) I wanted to run the test. This works but I still obviously would like to understand these other issues.

 

 

 

 

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Hi,

 

I had a chance to create a program that logs 5 seconds of data every 25 seconds.  After looking at your program I saw that I had the same settings.  I attached a screen shot of my data view and also attached my signal express project.  I noticed that the time the data was being sampled was correct and the log files were perfect.  The only discrepancy was that the log file time did not correspond to the actual time the data was acquired. 

Message Edited by Jordan F on 01-12-2009 01:03 PM
Regards,
Jordan F
National Instruments
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Thanks for taking a look at this. I took your project and ran it on my machine. The advanced logging did work. However, your code only included the DAQ voltage acquire. When I added the statistics step, the advanced logging reverted back to its erratic behavior. After some more testing, it appears that the advanced logging has a problem with analysis steps but still functions with processing steps. I couldn't find anything in the manual about problems logging analyzed signals. I should note that if I manually log the data (enable recording and let it free run) the logging captures both the raw and analyzed signals just fine. Is this a bug?

 

Thanks

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I added an analysis step (Statistics) as you did in your program and I was able to have it work properly with the setup I gave earlier.  Check this out to see if it works for you.  Hopefully we can narrow down this issue!

Regards,
Jordan F
National Instruments
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Hello All,

I have confirmed the issue reported on this post and have filed Corrective Action Request 144590 regarding the issue. This number can be used to trace a resolution of this issue in future releases of Signal Express.

 

Brief Summary: The number of times set for a log to be recorded reverts to 1 upon creation of the second log. This option is accessed on the Recording Options screen (View>>Recording Options) under the Start Condition menu.

Regards,
Margaret Barrett
National Instruments
Applications Engineer
Digital Multimeters and LCR Meters
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