Read from Measurement File Express VI - Time information

I need some assistance with a small problem with building reports of collected data. I don't see it very relevant, but I'm collecting data from several modules on a 9074 cRIO. I'm not using the cRIO the way it is intended, but it is perfect for my needs. Anyway, I'm collecting the different types of data in RT, then using the express VI "Write to Measurement File" with TDMS option selected and one time column only selected. Also one header, etc. Nothing fancy.
In another VI I want to use this collection of .tdms files to create an Excel report. Everything is working good however I need a time column for reporting my data. When I view the .tdms file using Excel Importer, the time column is there and perfect, with the next column a relative time (or iteration) and then columns with the signal names at top and all the data below. Perfect.
I'm similarly using the "Read from Measurement File" Express VI to get the data back the same way it went in. I have everything in it's correct place on building the Excel Report, but I haven't been able to find any way to include the first time column in my import. I can use "Get Attributes" Express VI to get the signal names from the read, but that's not going to help with the time data. How is it possible that Labview allows to put the time data there, but not retrieve it? I'm aware of the warnings that Timestamps aren't supported by TDMS file format vs LVM, but there MUST be a way to retrieve that time information if "Excel Importer" can do it.
If that time column in the TDMS file is somehow computed using the start timestamp and dt, can someone explain how to compute that for my report?
Unfortunately, I can't use the LVM format because I need to allow the users of these VI's the backup of using Excel Importer to see this data if my report generation VI is not functional.
I'll attach one of the TDMS files for illustration. The first column of the second worksheet is exactly the data I need for my report.
Attachments:
TDMS Imported.xls ‏28 KB

DylanC,
Your solution works as needed. Thank You.
I think I found a better solution though. Apparently if you convert a signal from the Express VI "Read from Measurement File" into a waveform the time data required is included, then you can convert to a string with a for loop and insert it as a row header into a table. The result gives me what I need. I attached a screenshot if someone is interested.
AWyers
Attachments:
TableFromTDMS.JPG ‏61 KB

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Data reading and writing problem? how to set " Read from Measurment File express.vi" 's readout datasize?

Dear all,
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Message Edited by weichengatech on 03-09-2006 12:00 AM

Hello,
There’s no real efficient way to read the file if you don’t
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Your going to just have to read a row at a time and add the results to
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Read From Measurement File... removes X Values of first column?

During one of our tests, two instruments were switched at the terminal by accident. I need to read in the massive lvm files, remove the wrong scaling and apply the correct scaling, while switching the values in the columns and right it all to new files. Simple right?
I wanted to use the Read from Measurement File.vi to make things easier, because the files are very large and I would like to analyze them 100 rows at a time. Some of the the files are around 1.5 Gigs in size so I need to read them in chunks.
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Below you can see the first column completely removed from the data.
This is extremely frustrating. By probing the signal out I can see the dynamic data attributes and the time column has already been removed, so I don't think that the signal to double array express vi is the problem, but I am not sure.
I am attaching my VI and a small data file to be analyzed. You can see what I mean.
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[will work for kudos]
Attachments:
Scaling Factor Correction.zip ‏1109 KB

That is a great workaround. The help talked about putting a check next to "read lines" but for the life of me I couldn't find where to do that. I wonder what other VIs have mystery check options in the right mouse click menu. I mean normally options like those are inputs, I thought. I'm going to start right clicking on every VI I drop to see if there are options there I never realized.
I would still have to use the set file position VI and specify the byte offset right? How would I know where that is? I guess each character is a byte and I would count the characters in the string retrieved and then offset by that amount on the next iteration using a shift register?
While waiting for help, I ended up using the read from text file and using the match string to look for the new line character, and using the spreadsheet string to array vi, analyzed the files line by line. Thats just because I couldn't easily come up with a regular expression to get 100 lines. It was slow but it worked.
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[will work for kudos]

Read from Measurement File to XY on Waveform Chart

Something pretty simple that is giving me a hell of a time right now.
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Solved!
Go to Solution.

Tasty,
More often than not I find Express VIs to be more trouble than they're worth. Here's an example of reading tab delimited data in from an .txt and plotting Y values versus X values on a graph. Hope it helps.
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Andrew
Attachments:
ReadData.vi ‏14 KB
data.txt ‏1 KB

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Hello,
I have a problem when trying to read a .lvm file through "Read from Measurements file" with the following block diagram
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A part of the lvm file for reference.
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Sorry meant to attach the lvm. Here it is. (Actually I had to put it in .txt because the forum wont let me upload a lvm file)
I unfortunately cannot share the full vi that record the data as I am not its owner/creator. I'll try to give as much info as I can with the relevant pictures attached, I hope it allows us to at least have an hint of where the problem might be.
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In the stacked sequence, the other pannels are similar to the one shown here: value read fron a variable, converted to dynamic and a signal attribute is set. The "start recording" control operation is "switch when pressed".
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Read LabVIEW Measurement File VI Multiple Times

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Attachments:
Error 4.vi ‏33 KB
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I have a VI where I save data using the ''Write To Measurement File utility''. When I open the .lvm file in the note pad I can see all the data correctly, but when I use the "Read From Measurement File" tool and try tho make a graph the data shown is not correct. Attached the .lvm file and one image of the chart that labview made using the "Read From Measurement File". If you open the lvm in the notepad you can see that the time column goes up to 22 sec. In the chart the time axis goes only up to 7,5 sec. What is going wrong??? Thanks
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Solved!
Go to Solution.
Attachments:
Chart.jpg ‏688 KB
teste.txt ‏156 KB

vitor22 wrote:
I tryed.
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Attachments:
Example_VI_BD.png ‏49 KB

Read from measurement file problem

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Attachments:
Write to LVM.vi ‏128 KB
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Solved!
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To err is human, but to really foul it up requires a computer.
The optimist believes we are in the best of all possible worlds - the pessimist fears this is true.
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Read from Measurement File Express VI - Time information

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