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How do I use the Signal Express Recording Start/Stop Conditions?

For the “just to clarify” question, I get data in Excel for one pulse (low voltage - high voltage - low voltage points) if I export to Excel from the “Data View” screen when the graph is stopped.  However, since you asked what happened if I exported while the data was being record, I clicked “Run”, waited a second or so, and tried to export the data the same way while it was running (and being recorded).  I got the same result in Excel (low voltage - high voltage - low voltage).

                      

If I remove the Start/Stop conditions, click Run, and export the data (from the Data View screen) while the graph is running I get the same data as before (low voltage - high voltage - low voltage). If I take the log that was created while the program was running I get thousands of points broken up into peaks (low voltage – high voltage – low voltage).  However, if you look at the attachment I have included (I copy/pasted the first 4000pts out of 10,000s) you will see that the points are broken into (1000 pt)/(1 sec) increments, each of which has one peak.  This is a problem because at 10Hz there should be 10 peaks per second.  

 

My advisor thinks that since it is recording 1 peak /second (when it should be doing 10 peaks/second) that in a list of say 100 peaks it might be recording peak #1, #11, #21, etc. and skipping the ones in between.

 

I will try your other suggestions also.

 

Thanks,

Physics Aide

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I changed the settings that you specified, reset the previous Start/Stop conditions, clicked "Run", waited for it to finish logging data (a few seconds), Converted the Log to ASCII, opened the file in Excel and had no data.

 

With in a few seconds I changed the "Monitor/Record" function to "Playback" tried to drag the new log to the screen and got the message "Log Is Not Prepared for Viewing: The selected log is not yet prepared for viewing.  You must wait until the log has finished recording to view it."

 

Physics Aide

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Message 12 of 17
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Hey Physics Aide,

 

Have you had a chance to try repairing SignalExpress yet? If you've made the change from the KnowledgeBase article involving changing the Prepare log data for viewing option, make sure that after the log is created you right click on the log and select Make Log Viewable. This is likely why you are getting that "Log Is Not Prepared for Viewing" message.

 

An additional thing you might want to try is to change the triggering on your oscilloscope. You indicated in your first post that changing the horizontal settings changed the actual data that you saw in SignalExpress, so some of these settings might be interfering with what you want to measure. I would suggest using Edge triggering for right now, and seeing if adjusting these settings allow you to view the correct data. 

 

Another question : Since you are taking these measurements from an oscilloscope, can you view the data correctly from the oscillscope (e.g. detaching the scope from your computer and viewing the scope's readout)?

Justin E
National Instruments R&D
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I haven’t repaired SignalExpress yet.  I tried to, but the computer said that there were supposed to be 2 disks to reinstall the program and I only could find one.  I’ll keep looking. 

 

In the mean time, I read the KnowledgeBase article and changed the settings.  

When I changed the “Prepare log data for viewing” I changed it to “After logging completes”.  When I looked for “Make Log Viewable” it didn’t give me that option, so I tried to move the log to "Playback" and got the “Log Is Not Prepared for Viewing” message.

 However, when I changed the setting to “Never” it did give me the “Make Log Viewable” option, which I clicked on.  When I tried to drag that log into “Playback” I got this message “Log Is Not Prepared for Viewing: The selected log is not prepared for viewing.  Once recording has completed, you must right-click on the log and select ‘Make log viewable’ before viewing it.”  [This makes no sense: the log was not in the process of recording at the time, and I had just clicked on the ‘Make log viewable’ option seconds earlier.]

 

The edge triggering is a good idea.  

 

As far as the horizontal settings go, the part I was changing (referenced in the first post) was the scale.  [Note: the 1 Hz referenced in the first post was supposed to be 10 Hz].  So basically I was just zooming in to see one peak or zooming out to see 10 peaks.  However, Signal Express seems to mostly only take data from what you can see on the screen (many points from one peak when zoomed in and few points from many peaks when zoomed out).  I thought that if I was zoomed in it might take more than just one or two points from each peak. 

 

The graph on the oscilloscope is the same as the one on the “Data View” in SignalExpress. The oscilloscope can be zoomed in or out manually when it is not attached to the computer.  I also know that SignalExpress is not somehow changing the actual values of the pulse through the oscilloscope because the pulses come from a signal generator (they are not generated by the oscilloscope itself).   

 

Thank you,

Physics Aide

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Message 14 of 17
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These logging errors might indicate something is wrong with your SignalExpress software. I'd continue to look for that disc and try repairing the software.

 

When you say that SignalExpress only takes data from what you can see on the screen, are you referring to the oscilloscope's screen? If so, this is likely expected since all SignalExpress is doing is adjusting the settings on the scope, and grabbing the data that's returned from the scope.

Justin E
National Instruments R&D
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Message 15 of 17
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I tried repairing SignalExpress, but I have some questions.  They are in the attached document.

 

Thank you,

Physics Aide

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Message 16 of 17
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Hey Physics Aide,

 

When you upgrade software, you may be introducing shared dependencies between programs. Some of these shared installer dependencies may have had a new version installed by another NI product and that product will be required in order to build the installer. In this situation, it looks like SignalExpress was installed before LabVIEW. The SignalExpress repair will try to repair everything installed with SignalExpress. Certain things in the SignalExpress install might have been updated by a later version of LabVIEW, and thus the repair needs to access what LabVIEW installed to fully repair SignalExpress.

Justin E
National Instruments R&D
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