Time with 'Write to measurement file'

Hello,
I am making an acquisition waveform. The integration time is 1s divided in 128 samples. When I execute the software, the datas are stored in a text file with 'Write to measurement file'. This text file is a continuous list of 128 numbers-packs in rows.
I want to add the time column (date+hour+minutes+secondes+1/10sec+1/100sec) in front of each number acquired. (And not only in front of the first number of the 128 package)
I have don t know how to add this.
Can you help me?
Thanks a lot.
(See file attached)
Attachments:
test3.vi ‏148 KB

Also, in the setup dialog for the Write Measurement File, there's an option to include an "X Column Value" that normally holds a timestamp.
Enable one of these options and any included timestamp in your waveform will go into this column. If you don't have a waveform, you can build an extra column in your array of data points with the needed timestamp and it will work the same.
Ed
Message Edited by Ed Dickens on 02-20-2007 03:37 PM
Ed Dickens - Certified LabVIEW Architect - DISTek Integration, Inc. - NI Certified Alliance Partner
Using the Abort button to stop your VI is like using a tree to stop your car. It works, but there may be consequences.
Attachments:
WLVMF Time Column.gif ‏9 KB

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Problem with Write To Measurement File Express VI not writing to file if file was deleted after the first call (7.1)

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The path/filename is passed into the function.
It works fine the first time around. If the file is deleted before the function is called again, an error occurs since LV is unable to find the file.
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Ok, I've edited the VI you posted to reproduce my error (this time with 8.0).
I added a "master stop" and "start log" button. To demonstrate my problem:
1. Run the VI
2. Click "START LOGGING" - c:\test.txt is created
3. Click "STOP" - c:\test.txt is closed
4. Delete the file c:\test.txt with Windows shell or explorer
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Attachments:
Write LV Meas File 2.vi ‏96 KB

Hi am trying to save Data into a write to measurement file vi using a NI PXI 1042Q with a real time mode but it is not working but when i run it with uploading it into the PXI it save in to the file

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Help with saving time stamps to "write to measurement file" excel format.

I am having problems saving the timestamps from my data to the write to measurement express vi for excel. My incoming data is converted from dynamic data to a 1d array for processing, which I understand you lose the time stamp data. I added a new array for time stamps but this array then cannot be converted back to the dynamic data that is requested to go into the write to measurement file express vi. I would prefer to leave the data in an array to be saved rather than converting it to a waveform so is there any way to add the time stamps from my 1d array back into the write to measurement file?

I set it up to build a waveform now but I am still having issues with it saving the correct timestamp. The time just incriments for every second (as it did before converting the dynamic data to the waveform). I attached a screenshot.
Attachments:
waveform.png ‏36 KB

Formatting the time stamp in "Write LabVIEW Measurement File"

When I use the "Write LabVIEW Measurement File" vi to write data
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How can I get the computer date and time or at least the time HH:MMS???
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PS, And how can I put some sensible label on each columns in the file?

Tom,
The vi I'm attaching demonstrates how to use the computer system time for the timestamp on your LVM file. It takes a reading from the DAQ Assistant and applies a system time stamp. It's in version 7.1, but let me know if you need it in version 7.0.
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Tyler S
Attachments:
LVM_timestamp_7_1[1].vi ‏265 KB

Include time stamp in Write to Measurement file

Dear Experts,
I would like to include the time stamp in the data sheet I saved using a Write to Measurement file. Currently only 1 column of data was saved without the time stamp. Is there anyway I can save the data together with its time stamp in a single file (side by side column)?
Thank you.
Regards,
CYTeoh

Did you configure the Express VI to create a time channel:
Christian

Write to Measurement File time column wrong starting value

I am using Write tp Measurement File express VI. I select to write one time column. The values writtent in the time column start from a value that does not seem to correspond to anything in the program -- sometimes as much as 2-3 days before the saving begins.
Can I force the starting value of time to something, or get it to write the time since we started saving, or something predictable?

Include code whenever available. Asking somebody to troubleshoot your software without any code is like asking your mechanic to fix your car without taking your car to him.
Source
I don't recommend using the Write Express VI. I recommend using the File I/O primatives because they allow for much more control over what gets written and how. Still I would expect the Express VI to be able to write time properly so I'd assume there is some kind of bug with the data being given to the function. Post some code so we can see what is going on.
Unofficial Forum Rules and Guidelines - Hooovahh - LabVIEW Overlord
If 10 out of 10 experts in any field say something is bad, you should probably take their opinion seriously.

"Write to measurement file" in labview doesnt show time instants of the waveform

Hi
I am trying to write my data into a file. I am using the "write to measurement file" for this purpose. But, the file shows only the magnitudes of the input waveform and not the time instants.
Can someone help me with this.
Thanks
Vijay Chand Ganti

Hi
Thanks for ur reply. I tried using the "unbundle by name", but thats only helpful for a cluster of elements.What i need is to
get the time instants of an analog signal (to verify its sampling rate).
I am using the example under NI example finder-->Analog Input R series.
Mine is an FPGA application and so im using the R series. I am anyways attatching the VI which i modified for my use.
Attachments:
Analog Input (Host)2.vi ‏375 KB

Samples number is not properly set with VI Express Write To Measurement File

Hello,
I have a strange problem with the VI Express Write To Measurement File.
When I generate the .lvm file the samples number for each channel is equal to 1
instead of 34 !
So when I use the VI Express / Input / Generate an arbitrary signal and I want to import
the generated signal... only one point (the first one) is imported...
I can manualy fix it by changing samples number in the lvm file using a text editor but that's a (very) dirty hack !
Here is an example of the generated LVM file
LabVIEW Measurement
Writer_Version    0.92
Reader_Version    1
Separator    Tab
Multi_Headings    No
X_Columns    One
Time_Pref    Absolute
Operator    scls
Date    2008/04/12
Time    10:35:58,322057
***End_of_Header***
Channels    2
Samples    1    1
Date    2008/04/12    2008/04/12
Time    10:35:58,323057    10:35:58,323057
X_Dimension    Time    Time
X0    0.0000000000000000E+0    0.0000000000000000E+0
Delta_X    1.000000    1.000000
***End_of_Header***
X_Value    Untitled    Untitled 1    Comment
0.000000    0.000000    20.000000
0.082000    10.000000    20.000000
0.182000    10.000000    25.000000
0.282000    20.000000    25.000000
0.382000    20.000000    30.000000
0.482000    30.000000    30.000000
0.582000    30.000000    35.000000
0.682000    40.000000    35.000000
0.782000    40.000000    40.000000
0.882000    50.000000    40.000000
0.982000    50.000000    45.000000
1.082000    60.000000    45.000000
1.182000    60.000000    50.000000
1.282000    70.000000    50.000000
1.382000    70.000000    55.000000
1.482000    80.000000    55.000000
1.582000    80.000000    60.000000
1.682000    90.000000    60.000000
1.782000    90.000000    65.000000
1.882000    100.000000    65.000000
1.982000    100.000000    70.000000
2.082000    110.000000    70.000000
2.182000    110.000000    75.000000
2.282000    120.000000    75.000000
2.382000    120.000000    80.000000
2.482000    130.000000    80.000000
2.582000    130.000000    85.000000
2.682000    140.000000    85.000000
2.782000    140.000000    90.000000
2.882000    150.000000    90.000000
2.982000    150.000000    95.000000
3.082000    160.000000    95.000000
3.182000    160.000000    100.000000
3.282000    170.000000    100.000000
PS : I also post my problem at
http://forums.lavag.org/Strange-behaviour-of-VI-Express-Write-LVM-t10570.html&gopid=44101#entry44101
Attachments:
generate_step_lvm.vi ‏119 KB

If I use the "one header per segment" option I get the following LVM file (see below)
But the problem is same !
I can't import this file in VI Express / Input / Generate Abitrary Signal (I only get one row... the first one)
I see three solutions :
- VI Express Write LVM has a bug ?
- I don't know how to use this VI Express correctly !
- VI Express / Input / Generate Abitrary Signal has a bug ?
LabVIEW Measurement
Writer_Version   0.92
Reader_Version   1
Separator   Tab
Multi_Headings   Yes
X_Columns   One
Time_Pref   Absolute
Operator   scls
Date   2008/04/12
Time   16:38:37,578
***End_of_Header***
Channels   2
Samples   1   1
Date   2008/04/12   2008/04/12
Time   16:38:37,592999   16:38:37,592999
X_Dimension   Time   Time
X0   0.0000000000000000E+0   0.0000000000000000E+0
Delta_X   1.000000   1.000000
***End_of_Header***
X_Value   Untitled   Untitled 1   Comment
0.000000   0.000000   20.000000
Channels   2
Samples   1   1
Date   2008/04/12   2008/04/12
Time   16:38:37,717   16:38:37,717
X_Dimension   Time   Time
X0   1.3899993896484375E-1   1.3899993896484375E-1
Delta_X   1.000000   1.000000
***End_of_Header***
X_Value   Untitled   Untitled 1   Comment
0.139000   10.000000   20.000000
Channels   2
Samples   1   1
Date   2008/04/12   2008/04/12
Time   16:38:37,739999   16:38:37,739999
X_Dimension   Time   Time
X0   1.6199970245361328E-1   1.6199970245361328E-1
Delta_X   1.000000   1.000000
***End_of_Header***
X_Value   Untitled   Untitled 1   Comment
0.162000   10.000000   25.000000
and so one ...

Time format in 'Write To Measurement File' express vi

Hi,
I'm using the 'Write To Measurement File' express vi to save data acquired using a PCI-6221 board and the DAQmx vi s. The acquisition is continuous.
When I set the 'number of samples per channel' property of the DAQmx Read.vi to -1 (ie, read all available samples), the time is saved in relative format. When I set any other value (ie a certain quantity of samples), the time is saved in absolute format.
Do you know why the vi does this, and if there's any way of controlling the time format ?
Thanks,
ps : I use Labview 8.0

Hi Scalpas,
I look into what I believe you are doing , but I didn't see the same results. Can you explain what datatype you are transferring to the Write to Measurement file VI? Or provide a sample of code that demonstrates the issue.
I think it might have to do with the DataType conversions when writing that file.
Sappster

Write to measurement file - Create or replace with confirmation

I'm using the "Write to measurement file.vi" and I want it to ask for confirmation if I try to save with a filename that already exists and then allow me to choose another file name or overwrite the old one. How can I do this?
Solved!
Go to Solution.

smercurio_fc wrote:
Ben wrote:
smercurio_fc wrote:
That Express VI does not have the capability you are seeking. ...
Help us Obe Wan, you're our only hope.
Ben
Did I misunderstand the question again?
No.
Spoiler (Highlight to read)
Your wording reminded me of the scene from Star Wars when Ben Kanobe di dthe force thing on the strorm troopers telling them "These are not the droid you seek."
Your wording reminded me of the scene from Star Wars when Ben Kanobe di dthe force thing on the strorm troopers telling them "These are not the droid you seek."
Its just Friday.
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Ben Rayner
I am currently active on.. MainStream Preppers
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Write to Measurement File: Time has minutes and seconds. Where are the hours?

Hi,
I have dynamic data acquired by Express VI: DAQ Assistant from a CompactDAQ and wired to Express VI: Write to Measurement File. In the resulting text file in the header the Date is recorded correctly in DD/MM/YYYY format. The Time field should be formatted HH:MMS.XXX but all I see is MMS.XXX. Is there a setting I should change to see the hours?
Regards,
Andrew.

Found the answer, sorry. Excel formatting issue. Not LabView after all.
Please delete this thread.
Cheers,
Andrew.

How to populate column titles for y values when using Write to Measurement File Express VI with a tab delimited text-based .lvm file?

The .lvm file generated by the Write to Measurement File Express VI includes column heading titles for the y values, but they are a default value of "untitled". See attached example of a sample file when opened in Excel, the values in question are highlighted. Is there a way to specify the column titles when the file is written?
This is a similar question to this posting, which received a work around response to use the Write to Spreadsheet File.vi, rather than a solution when using this VI.
Message Edited by Hightop Raven on 05-02-2007 03:37 PM
Attachments:
column_titles.gif ‏13 KB

Sorry for the late reply. I was out of the office Friday.
You can do it, but the code can get rather ugly. Under the hood, the dynamic data type (the dark blue wire) is an array of waveforms. In your case, the scalar values you convert to a dynamic data type are being converted to an array of waveforms, each waveform having one element. You have two options.
Explicitly convert your scalars to one-element waveforms (t0=0, dt=1) and add the title before conversion to a dynamic data type.
Convert your dynamic data type to an array of waveforms and loop through them to add the column labels. The conversion blocks are in the Signal Manipulation Express palette.
I would recommend 2, since it is the easiest to add. It is also the easiest to run only on the first iteration. Just put a case selector around the loop, wire the selection to the While loop iterator, and set the case containing the label code to 0. The default case simply passes through the dynamic data.
My apologies for not including a screen shot. I am in the process of upgrading my machine and can't run LabVIEW. If you need one, let me know and I can post one tomorrow.
This account is no longer active. Contact ShadesOfGray for current posts and information.

Write to measurement file at every n iterations

Hi guys,
I would like some help with saving data in labview 2010 SP1 (base development system). I am using a "Write to measurement fil express VI" inside a while loop and the data out from the DAQmn Read is wired to the signal in of the "Write to measurement fil express VI".
The way I have wired it is the VI saves the data as a text file after it has recorded 100 samples (the nuber of samples to read in this case was set to 100). I would like to know if there is a way to control the rate at which the express VI saves the data. As in, I want the express VI to save the data at specified time interval or at every nth iteration. I have attached the main VI and its 2 sub-VIs for reference. Please let know if anyone can help me resolve this issue. Thank you for your time and inputs in this regard.
Raj

Robert,
First, you must understand that the above code resides inside a loop. The blue square i terminal is known as the iteration terminal. It provides the current loop iteration count, starting from zero.
The first input (x) to the Quotient & Remainder Function comes from this iteration count (i) terminal of the loop.
The second input (y) to the Quotient & Remainder Function comes from the control N.
We wish to write to the measurement file every N iterations of the loop. If we take our current iteration count (i) and divide by our desired N, every Nth iteration of the loop, the remainder will be zero. For all other iterations, the remainder will be non-zero.
That being said, we check the remainder and compare it to zero. If it is zero, we will send a True value to the Enable terminal on the Write To Measurement File Express VI. Any time a True value is sent, we will write to file. Anytime a False value is sent, nothing will be written to the file.
The green new_file input on the Write To Measurement File Express VI is used when the "Save to series of files (multiple files)" radio button is selected in the Configure dialog box of this Express VI. When "Save to one file" is selected, this option does not apply, and so it is not included in the input list, which is why you are not seeing this.
This new_file input is used to tell the Write To Measurement File Express VI when to start writing to a new file.

Labview 9.0: Error 1 occurred at Write To Measurement File

Hi
Our University recently got the latest version of Labview (9.0 32-bit) which I installed today.The labview file I am using (my6008v6.vi) used to work fine with the older version (8.5 i think). My write-to-file VI is enabled at certain time intervals in order to log data. As soon as it is enabled for the second time I get the following error:
Error 1 occurred at Write To Measurement File->Copy of murray6008v6.vi
Possible reason(s):
LabVIEW: An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @.
=========================
NI-488: Command requires GPIB Controller to be Controller-In-Charge.
I made a simple file (simplew2f.vi) to test this, with a button which I can press to enable/disable the writing of data. I am able to start writing data and then stop writing data but as soon as I try resume the writing the same error occurs.
This confuses me greatly since this wasn't a problem using the old version and my Labview knowledge is minimal. Any help would be appreciated.
Attachments:
my6008v6.vi ‏214 KB
simplew2f.vi ‏64 KB

So, which VI are you having problems with? Sounds like both...
Okay... - sigh - where to start....
Well.. Let's start with a few comments.
1. Try to stay away from the Express VI. I know the Marketing guys at NI will not like me for saying so, but I am saying so. They are a nice marketing feature that Grumpy Old Men like myself do not like. They make it easy to write quick code.. And I will limit my comments to that. (It's not your fault.. )
2. The wiring on your diagram is not clear or easy to read. Yes, with additional time and double-clicking each wire I can tell where they are going. However, a rule of thumb, alway wire from Left to Right. Never right to left. And do not run the wires under objects, even the ones you are wiring to.
3. simplew2f.vi: You should put a small delay in the While Loop. I ran it three times and it wrote to the files without error. And yes, I used LV2009.
4. my6008v6.vi: Avoid wiring from the top of the While Loop. At frist, it looked like the data was coming out of the While Loop because the wires went to the left side of all the index node of the Index Array function.
You should set your Browse Option for the file path to "Files or Folders" and "New or existing". I did that and I was not getting the error message you described.
R
Message Edited by Ray.R on 03-03-2010 08:33 AM
Attachments:
pathProperty.PNG ‏13 KB

Time with 'Write to measurement file'

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