Read From Binary File doesn´t work on MCB2400 in LV2009 Embedded ARM

Hello,
I try to read a Binary File from SD-Card on my MCB2400 Board with LV2009 Embedded for ARM.
But the output is always 0, if I use my VI on the MCB2400. If use the same VI on the PC it works fine with the same binary file.
The
access to the SD-Card on the MCB2400 works in other cases finde, if I
try to read from a text-file it works without any problems.
Are thre any constraints for the "Read From Binary File"-Node in Embedded in comparison to the same node on PC ?
I have noticed that there is also a problem
with the reading of textfiles. If the sice of the file is about 100Byte
it doesn´t work anymore, too. I can´t understand it, because I read
always just one Byte. And even if the implementation in Labview is so
bad that it allways reads the total file in the ram it sould work. The
MCB2400 has 32MegaByte RAM, so 100Byte or even a few MegaByte should
work.
But this doesn´t seem to be the Problem for the Binary-Problem. Because even a 50byte Binary-File doesn´t work.
bye & thanks
amin
Solved!
Go to Solution.
Attachments:
SD_Card_Read-test.vi ‏12 KB

Hello,
thank you for your Help.
But I just want to read a Binary File, which is build by another program. And this is coded with 8Bit (like a normal Binary File) and not just with 7Bit (ASCII). So the workaround doesn't work in my case.
I posted the Test-VI in my first post (here once again as picture). And it works fine on the PC, but if I try it on my MCB2400 the "Read Form Binary File" Node doesn't work.
And it is also possible to open the Bin file with the "Read Text File" Node and see the cryptic content of the Bin-File. So the Problem seems to be in the "Read Form Binary File" Node.
bye & thanks again
amin
Message Edited by aminat on 09-30-2009 03:28 AM

Similar Messages

Reading from a file doesn't work...

Hi All,
I am tring to read from a file tickets.txt and when I do this
BufferedReader inFile = new BufferedReader (new FileReader("tickets.txt"));
StringTokenizer tokens = new StringTokenizer(inFile.readLine(), ":");StringTokenizer throws a null pointer exception... and I couldn't work out why... so I did this in between BufferedReader and StringToken
System.out.println(inFile);And it printed this on the screen... which is not in my file...
java.io.BufferedReader@1c78e57
Please Help,
Mike

C:\Program Files\Java Studio_JDK\s1studio\bin
is what it prints... which is not where my file is...
but it created a file there ... and I added stuff to the new file I found and it still prints null?
some of my code...
PrintWriter pw = new PrintWriter (new BufferedWriter (new FileWriter ("tickets.txt")));
BufferedReader inFile = new BufferedReader (new FileReader("tickets.txt"));
System.out.println(inFile.readLine());
BufferedReader stdin = new BufferedReader (new InputStreamReader(System.in));thats all in the main and thats all that really has anything to do with tickets.txt right now... everything else is commented out for now...once I manage to read the file then I will uncomment it...(the methods and stuff)
Thanks,
Mike

Read an avi file using "Read from binary file" vi

My question is how to read an avi file using "Read from binary file" vi .
My objective is to create a series of small avi files by using IMAQ AVI write frame with mpeg-4 codec of 2 second long (so 40 frames in each file with 20 fps ) and then send them one by one so as to create a stream of video. The image are grabbed from USB camera. If I read those frames using IMAQ AVI read frame then compression advantage would be lost so I want to read the whole file itself.
I read the avi file using "Read from binary file" with unsigned 8 bit data format and then sent to remote end and save it and then display it, however it didnt work. I later found that if I read an image file using "Read from binary file" with unsigned 8 bit data format and save it in local computer itself , the format would be changed and it would be unrecognizable. Am I doing wrong by reading the file in unsined 8 bit integer format or should I have used any other data types.
I am using Labview 8.5 and Labview vision development module and vision acquisition module 8.5
Your help would be highly appreciated.
Thank you.
Solved!
Go to Solution.
Attachments:
read avi file in other data format.JPG ‏26 KB

Hello,
Check out the (full) help message for "write to binary file"
The "prepend array or string size" input defaults to true, so in your example the data written to the file will have array size information added at the beginning and your output file will be (four bytes) longer than your input file. Wire a False constant to "prepend array or string size" to prevent this happening.
Rod.
Message Edited by Rod on 10-14-2008 02:43 PM

"Read From Binary File" function Help ambiguity

I must be getting tired, but for some reason a doubt crept in my mind as I was designing a new piece of code this morning:
"is the "Read From Binary File" using the last file position or is it starting from the beginning of the file?"
"That's a stupid question", I told myself.
"I used this function a million times and have always assumed it is reusing the last file position. Moreover, there is no file offset input to that function, so WTH am I afraid of?"
So, for kicks, I fired up the Help window and read the following description (*):
Reads binary data from a file and returns it in data. How the data is read depends on the format of the specified file. This function does not work for files inside an LLB.
(*) BTW, has anybody ever complained that you can't select and copy anything from the floating Help Window?
Not much there. I particularly admire the phrasing of the second sentence... What about: "This function can do a lot of things, but it would much to complex to describe this is extensive details, so if you are asking, you probably can't afford using it"?
Anyhow, I clicked on the "Detailed Help" and got this (among other things):
Use the Set File Position function if you need to perform random access.
WHAT? I am pretty darn sure I DO NOT USE the Set File Position when I read a file in successive and contiguous chunks. I just pass the file refnum into a shift register and back to the function and that's it.
Now, the description of the "Refnum Out" ouput says: If file is a refnum or if you wire refnum out to another function, LabVIEW assumes that the file is still in use until you close it. Translated in plain English, is that supposed to mean that if the file is not closed it is open, or is that implying that it contains more info that just "the file is open and can be found here"?
I started searching around and finally ended up with the entry for "refnums, file I/O". Down the bottom of the (long) article, I found this under the heading "References to Objects or Applications" (but nothing specific to files, BTW):
...LabVIEW creates a refnum associated with that file, device, or network connection...
[...] LabVIEW remembers information associated with each refnum, such as the current location for reading from or writing to the object and the degree of user access, so you can perform concurrent but independent operations on a single object. If a VI opens an object multiple times, each open operation returns a different refnum. LabVIEW automatically closes refnums for you when a VI finishes running, but it is a good programming practice to close refnums as soon as you are finished with them to most efficiently use memory and other resources.
So it seems that my recollection was correct. I do not know what the "degree of user access" for a file is, but that's not the topic of today's post.
So, my point is: the Help File for this function is incomplete or ambiguous at best. Please correct it. And provide a link to the "refnum, file I/O" Help entry in its detailed Help. It would H E L P...
Thanks for reading.

Reading in succesive chunks is *NOT* random access. An open file always has
a current position, which is updated with each read or write operation.
You only need to set the file position if you want to start elsewhere.
LabVIEW Champion . Do more with less code and in less time .

"Read from Binary File" and efficiency

For the first time I have tried using Read from Binary File on sizable data files, and I'm seeing some real performance problems. To prevent possible data loss, I write data as I receive them from DAQ, 10 times per second. What I write is a 2-D array of double, 1000 data points x 2-4 channels. When reading in the file, I wish I could read it as a 3-D array, all at once. That doesn't seem supported, so I repeatedly do reads of 2-D array, and use a shift register with Build Array to assemble the 3-D array that I really need. But it's incredibly slow! It seems that I can only read a few hundred of these 2-D items per second.
It also occurred to me that the Build Array being used in a shift register to keep adding on to the array, could be a quadratic-time operation depending on how it is implemented. Continually and repeatedly allocating bigger and bigger chunks of memory, and copying the growing array at every step.
So I'm looking for suggestions on how to efficiently store, efficiently read, and efficiently reassemble my data into the 3-D array that I need. Perhaps I could simplify life if I had "write raw data" and "read raw data" operations that write and read only the numbers and no metadata.then I could write the file and read it back in any size chunks I please -- and read it with other programs besides. But I don't see them in the menus.
Suggestions?
Ken
Solved!
Go to Solution.

I quote the detailed help from Read from Binary File:
data type sets the type of data the function uses to read from
the binary file. The function interprets the data starting at the current file
position to be count instances of data type.
If the type is an array, string, or cluster containing an array or string, the
function assumes that each instance of that data type contains size information.
If an instance does not include size information, the function misinterprets the
data. If LabVIEW determines that the data does not match the type, it sets data
to the default for the specified type and returns an error.
So I see how I could write data without any array metadata by turning off "prepend array or string size information", but I don't see any way to read it back in such bare form. If I did, I'd have to tell it how long an array to read, and I don't see where to do that. If I could overcome this, I could indeed read in much larger chunks.
I'll try the auto-indexing tunnel anyway. I didn't tell you the whole truth, the 3-D array is actually further sliced up based on metadata that I carry, and ends up as a 4-D array of "runs". But I can do that after the fact instead of trying to do it with shift registers as I'm reading.
Thanks,
Ken

Create AAC from Wav file doesn't work

I've converted many WAV files to AAC and it worked fine. The last few times I've tried it it isn't working. I hear the bleep which I think indicates it's been converted but I can't find it anywhere so assume it didn't happen.
I have Windows XP. I am running iTunes 10.3.1.55
Any ideas would be appreciated.
Thanks,
Ginny

Hello,
thank you for your Help.
But I just want to read a Binary File, which is build by another program. And this is coded with 8Bit (like a normal Binary File) and not just with 7Bit (ASCII). So the workaround doesn't work in my case.
I posted the Test-VI in my first post (here once again as picture). And it works fine on the PC, but if I try it on my MCB2400 the "Read Form Binary File" Node doesn't work.
And it is also possible to open the Bin file with the "Read Text File" Node and see the cryptic content of the Bin-File. So the Problem seems to be in the "Read Form Binary File" Node.
bye & thanks again
amin
Message Edited by aminat on 09-30-2009 03:28 AM

Reading a binary file using the type cast function is not working

Hello
I am trying to read a binary file. Using the Read from binary file and type cast functions I can actually get the information from the file.
I set an indicator in the “Normal” option in Properties. I can read the header and footer but not the body of the file; For the body of the file all I can see is characters of the type
“C¾ Ü Qþ X@ “. One of the other options, Password, seems to provide an output of just the characters that were originally written, but then again, I can not read the characters because it is only asterisks and I can not copy them onto a word processor either.
I tried setting the indicator in Hexadecimal mode, then creating a local variable that acts as a control and use the type cast function again to see if could convert the Hexadecimal string to readable ASCII characters; unfortunately, this did not work either.
I don’t know what else I should try or if there is something that I may not be doing right and for that reason I am not getting the desired results. I hope someone has an idea about this issue.
Regards,
Roberto

Thank you for your reply,
Well, actually I don’t have any information about this file. I will try to obtain information about it though.
This is a file that contains velocity information; there are 65 channels that form a velocity profile in a pipe. Also, there are 4096 velocity profiles. I don’t know what is the format of these values.
The software that creates the file provides a text file. Using this text file the velocity information can be processed and then plotted.
I want to avoid all these intermediate steps and read, process and plot everything using only LabView. BTW, I am using LabView 8.2
Roberto

Problems reading from a file

Hey,
I have this file that I need to read so i can handle the contents. It was created in MSDOS and as I have very little experience in that topic, I wondered if anyone can point me in the right direction. I tried reading it as a ascii and binary file but neither work, I'm really just guessing though.
The file has no extension. Hence I can't upload it to the forum. Its made up of mostly meaningless strings of characters.
Any help is appreciated,
Regards,
Rkll

Rkll wrote:
Ya you're exactly right, its parsing the data that is the problem. I have done what you said and attached it as a .txt file. My inital thought was that it was a collection of binary digits but I was unable to read them with the built in Labview read binary file VI. Although maybe I had a setting wrong or something.
This has nothing to do with the Read From Binary File VI, or any setting. That functions does not magically know the format of a file, just like any binary file read for any other programming language. Thus, you have to tell it how to interpret the data. You can tell it to read the file as a series of bytes, and it will dutifully return to you an array of U8 integers. Or, you tell it to read it as a series of 16-bit integers and it will dutifully return to you an array of I16. It will give you what you tell it to give you.
Looking at the file I can see some header information, though it's not clear what all the spaces are being used for. I can't tell whether they're padding for a section, or what. As I noted, do you have any idea as to the format of the file? You said you're updating an old computer system. Any documentation?

Read from I16 file

Dear,
I used to use Read from I16 file.VI, but since I'm using LabView 2009, I'd like to use "Read from binary file.VI".
I've looked at the previous posting and tried the suggestions, but I still got a problem.
Could you help me to figure this out? By the way, I'm using LabView 2009 Spring (Professional version). The VI I'm trying to replace is shown below.
Thanks,
Jay

In order for it to work the way you have it displayed there, you will need to wire a 2D array constant (make sure the representation is I16) to the data type input of the read from binary file.vi
National Instruments
Applications Engineer

Problem with reading from bin file into Vector

What am I doing wrong? It works fine to write the vector to the bin file and then read from it. But if I try just to read from the file it wont work.
Does anybody has any good advice to give when it comes to reading data form a bin file??
import javax.swing.*;
import java.util.*;
import java.io.*;
class Binaerfil
     public static void main (String [] args) throws IOException, ClassNotFoundException{
          ObjectOutputStream utFil = new ObjectOutputStream (new FileOutputStream("HighScoreLista.bin"));
          int po = 50;
          Spelare s;
          Spelare s1, s2, s3, s4, s5,s6,s7,s8,s9,s10;
          String f�rNamn;
          Vector v = new Vector();
          s1 = new Spelare("Mario", 100);
          s2 = new Spelare("Tobias",90 );
          s3 = new Spelare("Sanja", 80 );
          s4 = new Spelare("Marko", 70 );
          s5 = new Spelare("Sofia", 60 );
          s6 = new Spelare("Kalle", 50 );
          s7 = new Spelare("Lisa", 40 );
          s8 = new Spelare("Pelle", 30 );
          s9 = new Spelare("Olle", 20 );
          s10 = new Spelare("Maria",10 );
          v.add(s1);
          v.add(s2);
          v.add(s3);
          v.add(s4);
          v.add(s5);
          v.add(s6);
          v.add(s7);
          v.add(s8);
          v.add(s9);
          v.add(s10);
          System.out.println ("Before writing to file");
          System.out.println(v);
          //Write to file
          utFil.writeObject (v);
          utFil.close();
     ObjectInputStream inFil = new ObjectInputStream (new FileInputStream("HighScoreLista.bin"));
          v =(Vector) inFil.readObject();
     System.out.println (v);
          inFil.close();
}

Because what you are writing to the file is a vector, that is all you can get out. You are actually reading a single Object from the file which you can cast to a Vector, from which you can access the data stored inside. If you want to read the Spelare instances from the file, you will have to save them individually to the file. You will have to implement Serializable and look up the API to do that.

Read From Measurement File doesn't work

I am using LV 8.0 and have a daq program that writes data to a .lvm file every two seconds. When I use the Read From Measurement File block the resulting waveforms have dt set to 0 rather than 2 as it says in the file. All the y values are good but I have to ue the Build Waveform function to set dt to 2 but I should not have to do that right? I can see dt is 0 using a probe on the output of the Read Measurement Function.. I have attached a sample .lvm file but I have changed the extension because this site would not accept a .lvm file!
Phil
Attachments:
Profile.xls ‏6 KB

Jeff B,
Sorry for the delay, I have been travelling for a couple of weeks. I took a look at the profile and your are right, it was modified incorrectly. When the data are taken and stored as a CSV file using Write to Labview Data file, the program always sets the sample number to 1 because it is being called to append one sample each time through the timing loop. Since the number of samples is wrong, I was modifying the number aftewards to get the read to work. After your comment, I used jedit to modify it rather than excel and it worked. I could change the program to store the data only once after the run is finished to eliminate having to mess with the data. I don't know how else to fix it.
Thanks,
Phil

LabVIEW for ARM 2009 Read from text file bug

Hello,
If you use the read from text file vi for reading text files from a sdcard there is a bug when you select the option "read lines"
you cannot select how many lines you want to read, it always reads the whole file, which cause a memory fault if you read big files!
I fixed this in the code (but the software doesn't recognize a EOF anymore..) in CCGByteStreamFileSupport.c
at row 709 the memory is allocated but it tries to allocate to much (since u only want to read lines).
looking at the codes it looks like it supposed to allocated 256 for a string:
Boolean bReadEntireLine = (linemode && (cnt == 0));
if(bReadEntireLine && !cnt) {
  cnt = BUFINCR;    //BUFINCR=256
but cnt is never false since if you select read lines this is the size of the file!
the variable linemode is also the size of the file.. STRANGE!
my solution:
Boolean bReadEntireLine = (linemode && (cnt > 0)); // ==
if(bReadEntireLine) {    //if(bReadEntireLine && !cnt) {
  cnt = BUFINCR;
and now the read line option does work, and reads one line until he sees CR or LF or if the count of 256 is done.
maybe the code is good but the data link of the vi's to the variables may be not, (cnt and linemode are the size of the file!)
count should be the number of lines, like chars in char mode.
linemode should be 0 or 1.
Hope someone can fix this in the new version!
greets,
Wouter
Wouter.
"LabVIEW for ARM guru and bug destroyer"

I have another solution, the EOF works with this one.
the cnt is the bytes that are not read yet, so the first time it tries to read (and allocate 4 MB).
you only want to say that if it's in line mode and cnt > 256 (BUFINCR) cnt = BUFINCR
the next time cnt is the value of the bytes that are not read yet, so the old value minus the line (until CR LF) or if cnt (256) is reached.
with this solution the program does not try to allocate the whole file but for the max of 256.
in CCGByteStreamFileSupprt.c row 705
if(linemode && (cnt>BUFINCR)){
cnt = BUFINCR;
don't use the count input when using the vi in line mode. count does not make sense, cnt will be the total file size. also the output will be an array.
linemode seems to be the value of the file size but I checked this and it is just 0 or 1, so this is good
update: damn it doesn't work!
Wouter.
"LabVIEW for ARM guru and bug destroyer"

'read from text file' erases the file

I am trying to read text in from a text file. This is the exact code I am using. For some reason the output from 'read from text file' contains all the text that was originally in the file, but after the code executes the file is empty. I have several other vi's which use the same code and the file is fine. But whenever I run this code in this one specific vi the text file gets erased.

What is in the rest of that "specific vi"? I just tried the code you show, in v2011, and it works as expected, doesn't clear file.
What version are you running? Can you add an error out, or make sure error output is on in your LabVIEW configuration?
Putnam
Certified LabVIEW Developer
Senior Test Engineer
Currently using LV 6.1-LabVIEW 2012, RT8.5
LabVIEW Champion

What's the best way for reading this binary file?

I've written a program that acquires data from a DAQmx card and writes it on a binary file (attached file and picture). The data that I'm acquiring comes from 8 channels, at 2.5MS/s for, at least, 5 seconds. What's the best way of reading this binary file, knowing that:
-I'll need it also on graphics (only after acquiring)
-I also need to see these values and use them later in Matlab.
I've tried the "Array to Spreadsheet String", but LabView goes out of memory (even if I don't use all of the 8 channels, but only 1).
LabView 8.6
Solved!
Go to Solution.
Attachments:
AcquireWrite02.vi ‏15 KB
myvi.jpg ‏55 KB

But my real problem, at least now, is how can I divide the information to get not only one graphic but eight?
I can read the file, but I get this (with only two channels):
So what I tried was, using a for loop, saving 250 elements in different arrays and then writing it to the .txt file. But it doesn't come right... I used 250 because that's what I got from the graphic: at each 250 points it plots the other channel.
Am I missing something here? How should I treat the information coming from the binary file, if not the way I'm doing?
(attached are the .vi files I'm using to save in the .txt format)
(EDITED. I just saw that I was dividing my graph's data in 4 just before plotting it... so It isn't 250 but 1000 elements for each channel... Still, the problem has not been solved)
Message Edited by Danigno on 11-17-2008 08:47 AM
Attachments:
mygraph.jpg ‏280 KB
Read Binary File and Save as txt - 2 channels - with SetFilePosition.vi ‏14 KB
Read Binary File and Save as txt - with SetFilePosition_b_save2files_with_array.vi ‏14 KB

UITextField from .xib file doesn't show

A UITextField from .xib file doesn't show when it's page comes up on the iPhone simulator.
The View looks fine in Interface Builder, and no warnings are thrown to Console or IB's Info window.
On the Simulator the View comes up and a Label and a Switch show, but not a UITextField. The Objects are on the same row and their bounds are all appropriate.
I don't see anything in the Text Field Attributes of IB that is problematic, plus I've probably tried all combinations of settings. In Connections there is a reference to a File's Owner attribute.
I have been able to create a UITextField programmatically.

Worked around the problem by deleting the UITextField from the .xib and re-creating it.

Read From Binary File doesn´t work on MCB2400 in LV2009 Embedded ARM

Similar Messages

Maybe you are looking for