Frequency response vi and writing to lvm files

I'm having trouble writing the magnitude y/x of the frequency response vi to an .lvm file.
I don't get any samples in my file when I run the program.
Any idea what I'm doing wrong here?
Attachments:
testernw.vi ‏381 KB

Hi,
If you place indicators immediately before and after the frequency response express VI, what do they show? Are there any differences between the input data before and after the conversions are applied? I tried putting together a simple VI that takes two simulated signals, inputs them into the frequency response graph, and then outputs it to a file. It appears to work fine, as long as the two inputs are at a different frequency.
What version of LabVIEW are you using? Where specifically are you reading the 0 values?
Regards,
Lauren
Applications Engineering
National Instruments

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DAQ Freq resp (req)_trial.vi ‏121 KB

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Problem reading and ploting large lvm files

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Reading and writing from a file

I am trying to read and write to a file so that I may store an array of string and a double in my application, but I have come upon a couple of problems; first when I put my file path into the path constant it will say that the file is not there ever though it is (so I have to force the issue and when the application asks for a file I have to browse and add the files), secondly when I run the program and it reads from the file it does not display the strings or doubles immediately instead I have to hit the submit button and than they finally come up, thirdly when I reset my values in the .txt files and put in my string and double and hit submit the array jumps one spot and starts at the index of 1 (array[1]) if anyone can help I would appreciate it a lot.
here is my code:
Harold Timmis
[email protected]
Orlando,Fl
*Kudos always welcome
Solved!
Go to Solution.
Attachments:
testingfileIO.vi ‏30 KB
double.txt ‏1 KB
string.txt ‏1 KB

Harold Timmis wrote:
I am trying to read and write to a file so that I may store an array of string and a double in my application, but I have come upon a couple of problems; first when I put my file path into the path constant it will say that the file is not there ever though it is (so I have to force the issue and when the application asks for a file I have to browse and add the files),
I don't see that behavior at all about forcing the issue. Why are you using Not a Path constants? Why not turn those constants into controls you put on your front panel?
secondly when I run the program and it reads from the file it does not display the strings or doubles immediately instead I have to hit the submit button and than they finally come up,
Put your array indicators before your event structure rather than after. Think dataflow. The code pauses at the event structure waiting for an even to fire. Only when it does (such as hitting the submit button) does the data get written to the array indicators.
thirdly when I reset my values in the .txt files and put in my string and double and hit submit the array jumps one spot and starts at the index of 1 (array[1]) if anyone can help I would appreciate it a lot.
I don't see this behavior either. How come your double.txt file has names in it, and your string.txt file has doubles in it?

Help on reading and writing to a file !!!!!!!!!!!!!!!!

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Building array and writing to multiple files

Greetings,
I have a VI wherein, I am collecting data from 3 channels (using Global Virtual Channels with scaling). I am collecting 100 samples at a time with sampling frequency of 1000 Hz. I am then taking average and st. dev of 100 data points/channel and write it to a file (‘*.dat’). I would like to limit the file size to 1000 entries, and so after that limit is reached I would like to create a new file and write the subsequent set of data to the next file and so on. I am doing this in a case structure, wherein I build an array of the values until the condition of file limit is reached and then I write that array to a ‘*.dat’ file. (I’m hoping that this logic is correct, if not please suggest the correct method)
I am also taking average and st. dev of data/channel over period of 1 sec and write it to another ‘*.sum’ file. The VI has other features like writing time stamp to file, stopping the VI after preset time limit is reached or certain safety limit is reached.
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Error 7 occurred at Open/Create/Replace File in Global Channel with Multiple file Write.vi
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LabVIEW: File not found. The file might have been moved or deleted, or the file path might be incorrectly formatted for the operating system. For example, use \ as path separators on Windows, : on Mac OS X, and / on Linux. Verify that the path is correct using the command prompt or file explorer.
=========================
NI-488: Nonexistent GPIB interface.
I have indicated the location of the error in the attached picture, as well as I’m attaching the VI.
I would really appreciate if someone would tell me what is causing the error and how to fix it.
Thanks,
Dinesh
Solved!
Go to Solution.
Attachments:
Block Diag.png ‏121 KB
Global Channel with Multiple file Write.vi ‏515 KB

I did try that but it does not solve the problem. I think I'm missing something while building the array in the Case Structure. I would like to write the average & st. dev values/channel in an array while the loop coount < file limit, and once the file limit is reached write that array to a *.dat file. And keep repeating this procedure till the target time is reached.
Another issue that I discovered is that TestFile_1.dat is not generted, after TestFile_0.dat TestFile_2.dat gets generated. I'm not sure why this is happening.
I would really appreciate if you would take another look and suggest some debugging tips.
Thanks.
P.S. I am attaching the updated VI
Attachments:
Global Channel with Multiple file Write.vi ‏515 KB

READING AND WRITING FROM A FILE(WRITTEN IN ANOTHER LANGUAGE)

# Comment
INTEGER Declares integer type variable
STRING Declares string type variable
LET Assigns a variable
CALCULATE Performs an arithmetic calculation
PRINT Writes data to the console
PRINTLN As print, but followed by a new line
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Tim Brailsford, 2007
G64ICP
COMMENT
Any line beginning with the # character is completely ignored.
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The INTEGER reserved word declares an Integer variable, and assigns a default value of 0 to it.
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INTEGER myInt
This example is equivalent to the Java statment "int myInt=0;"
STRING
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STRING myString
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LET
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CALCULATE
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To the left is an example TPL input file , to
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Tim Brailsford, 2007
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Hai I have one doubt in doing other peoples homework for them. Why bother?

Hoping for a quick response : EXP and Archived REDO log files

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Bruce Davis wrote:
Amardeep Sidhu
Thank you for your quick reply. I am reading in the other responses that since I am using EXP without consistent=y, I might not even have a backup. The application vendor said that with this dmp file they can restore us to the most recent backup. I don't really care for this strategy as it is untested. I asked them to verify that they could restore us and they said they tested the dmp file and it was OK.
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Best Regards
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Need Help: UTL_FILE Reading and Writing to Text File

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PLEASE ADVISE...

Hi,
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SHOW ERRORSIf you don't have an EXCEPTION section, the default error handling will print an error message, spcifying exactly what the error was, and which line of your code caused the error. By using your own EXCEPTION section, you're hiding all that information. I admit, the error messages aren't always as informative as we'd like, but they're never less informative than "Unknown UTL_FILE Error'. Don't use your own EXCEPTION handling unless you can improve on the default.
Remember that anything inside quotes is case-sensitive. If your file contains upper-case 'FOO', then it won't be "LIKE 'foo%' ".
Edited by: Frank Kulash on Dec 7, 2011 1:35 PM
You may have noticed that this site normally doesn't display multiple spaces in a row.
Whenever you post formatted text (such as your code) on this site, type these 6 characters:
\{code}
(small letters only, inside curly brackets) before and after each section of formatted text, to preserve spacing.

Issue with Reading and Writing to a File

Hello all,
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Recording data at particular iterations and writing to text file

Hi all,
this is my first time posting on the NI boards. I'm running into a couple problems I can't seem to figure out how to fix.
I'm collecting data using a LabJack U3-HV daq. I've taken one of the out-of-the-box streaming functions that comes with the LabJack and modified it for my purposes. I am attempting to simply save the recorded data to a text file in columns, one for each of my 4 analog strain gauge inputs, and one for time. For some reason when the 'write to measurement file.vi' executes it is puts everything in rows, and the data is unintelligible.
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Attachments:
3.5LCP strain gages v2.vi ‏66 KB

Hey carfreak,
I've attached a screenshot that shows three different ways of trying to keep track of incrementing data and/or time in a while loop. The top loop just shows a program that demonstrates how shift registers can be used to transfer data between loops. This code just writes the iteration value to the array using the Build Array function.
The first loop counts iterations in an extremely round-about way... the second shows that really you can just build the array directly using the iteration count (the blue "i" in the while loop is just an iteration counter).
The final loop shows how you can use a time stamp to actually keep track of the relative time when a loop executes.
Please note that these three should not actually be implemented together in one VI. I just built them in one BD for simplicity's sake for the screenshot. As described above, the producer-consumer architecture should be used when running parallel loops.
Does that answer your question?
Chris G
Applications Engineer
National Instruments
Attachments:
While Loops and Iterations.JPG ‏83 KB

Reading and writing u16 binary file to a new file

Hello all,
a very simple thing that I just don't seem to be able to figure out. I have a file containing 1024bytes of unsigned 16bit words. I can read it successfully with the right value being displayed. But then I try to write these values to a new file, I can no longer read the same value (in fact it's all grayed out 0) from the newly written file. The newly written file has the right size 1024 bytes, but I don't seem to obtain the right information. I made sure the endian are the same, little-endian.
Attached is my basic VI, and the .dat file is the file containing the binary information.
I'm not using copy file because once I get this figure out, I'll need to append more of the Scan.dat file to one single file.
Thank you!
Solved!
Go to Solution.
Attachments:
read_write_binary_u16.zip ‏11 KB

I would put some wait time between the write and the read. It may be a good idea to actually close the file in between.
I have a feeling that you may not have allowed enough time to actually have the file written out before you read it again. That or since it is still open, the file pointer is at the end of the file and you are trying to read all the bytes starting at the end, which means you get nothing.
Not sure of the exact issue, but those two things comes to mind.

Frequency response vi and writing to lvm files

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