Write to binary files

Similar Questions

• write a binary file per day / / show the minute samples of 1 in 1

  Well guys, I know how to write a binary file...

  u run your program... Put the name you want the binary and writes...

  but now I have to write a binary file per day... How can I do?

  I do a follow-up on the tension and current... and I want to write the RMS of each day

  2009-09-09, 09/10/2009, 11/09/2009

  can someone help me with this?

  ------------------

  Another issue is that, in this program I monitors 3 voltages and currents 3 all the time... and show it to a customer via TCP/IP

  I want to know... How can I show this... every hour or every minute...

  I have 3600 samples per second... so I need like integrate and show every minute media... or second... or time... not ALL THE TIME... the value changes so fast that I can still see this... put a (ms) waiting work... but I need see the tensions and current than in a time like 1 of 10 in 10 minutes or 1 minute...... How can I do?

  Thank you guys!

  I'll download the vi and sub - vi so that you can better see what I'm talking about!

  
  

• save data in binary file

  Hello

  I have 700 2D double table to save and I would save in 700 different .dat extension (binary) files. I know that I can save a table in a binary format, but using a dialog box that opens a window so that I can choose the file. Since there are 700 table I don't want to have to choose the right way every time.

  I use a dialog box create a folder where I want to save 700 files. For now I earn 700 tables in the text file of 700 different using the "write to the spreadsheet file" VI and I works well, but it creates text files...

  Is it possible to do the same thing but by memorizing the data in the binary file and without using a bow of dialogue for each file?

  Thanks in advance

  Use writing binary vi to write in binary file. http://zone.NI.com/reference/en-XX/help/371361J-01/Glang/write_file/

  You could ask the user to select the folder you make below and then programatically generate paths, something like this:

  

• Write to the Cluster size in binary files

  I have a group of data, I am writing to you in a file (all different types of numeric values) and some paintings of U8. I write the cluster to the binary file with a size of array prepend, set to false. However, it seems that there are a few additional data included (probably so LabVIEW can unflatten on a cluster). I have proven by dissociation each item and type casting of each, then get the lengths of chain for individual items and summing all. The result is the correct number of bytes. But, if I flattened the cluster for string and get this length, it is largest of 48 bytes and corresponds to the size of the file. Am I correct assuming that LabVIEW is the addition of the additional metadata for unflattening the binary file on a cluster and is it possible to get LabVIEW to not do that?

  Really, I would rather not have to write all the elements of the cluster of 30 individually. Another application is reading this and he expects the data without any extra bytes.

  At this neglected in context-sensitive help:

  Tables and chains in types of hierarchical data such as clusters always include information on the size.

  Well, it's a pain.

• Strange binary file write behavior

  Something a little strange when I try to write data to a binary file. I have reproduced the issue in the StrangeBinaryFileBehaviour.vi which is attached below.

  I simply write two bytes in a binary file and yet my hex editor/Viewer tells me I have 6 bytes of data, a screenie of the discharge of the binary hexadecimal editor is also attached

  Maybe that I lose the plot and I'm missing something, forgive it is late on a Friday

  Stroke

  Wire a FAKE to the Terminal "prepend array or string size...? The default value is TRUE, so that you get extra bytes, depending on what it is to wire.

  For a 1 d array, you would get 4 extra bytes to the size of the array (I32) and tha of what you see.

• Write binary file structure and add

  I have a very simple problem that I can't seem to understand, which I guess makes that simple, for me at least.  I did a little .vi example that breaks down basically what I want to do.  I have a structure, in this case 34 bytes of various types of data.  I would iteratively write this structure in a binary as the data in the structure of spending in my .vi will change over time.  I'm unable to get the data to add to the binary file rather than overwrite since the file size is still 34 bytes bit matter how many times I run the .vi or run the for loop.

  I'm not an expert, but it seems that if I write a structure 34 bytes in a file of 10 times, the final product must be a binary file of 340 bytes (assuming I'm not padded or preceded by size).

  A really strange thing is that I get the #1544 error when I wire the refnum wire entry on the function of writing file dialog, but it works fine when I thread the path of the file directly to the write function.

  Can someone melt please in and save me from this task of recovery?

  Thanks for all the help. Forum rules of NEITHER!

  Have you considered reading the text of the error message? Do not set the "disable buffer" entry to true - just let this thread continues. Why you want to disable the buffering?

  In general, the refnum file must be stored in a register to shift around the loop instead of using the spiral tunnels, that way if you have zero iterations you will always get through properly file refnum. In addition, there is no need to define the Position of file inside the loop, since the location of the file is always the end of the last entry, unless it is particularly moved to another location. You might want it once out of the loop after you open the file, if you add an existing file.

• write 1 d digital table in a binary file and start a new line or insert a separator for each loop writing file

  Hello:

  I'm fighting with digital table of 1 d writeing in a binary file and start a new line or insert a separator for each loop writing file. So for each loop, it runs, LABVIEW code will collect a table 1 d with 253 pieces of a spectrometer. When I write these tables in the binay file and the following stack just after the previous table (I used MATLAB read binary file). However whenever if there is missing data point, the entire table is shifted. So I would save that table 1-d to N - D array and N is how many times the loop executes.

  I'm not very familiar with how write binary IO files works? Can anyone help figure this? I tried to use the file position, but this feature is only for writing string to Bodet. But I really want to write 1 d digital table in N - D array. How can I do that.

  Thanks in advance

  lawsberry_pi wrote:

  So, how can I not do the addition of a length at the beginning of each entry? Is it possible to do?

  On top of the binary file write is a Boolean entry called ' Prepend/chain on size table (T) '.  It is default to TRUE.  Set it to false.

  Also, be aware that Matlab like Little Endian in LabVIEW by default Big Endian.  If you probably set your "endianness" on writing binary file as well.

• I wrote the software for 33 years. I have a lot of apps. I would use html/xml to replace my aging FDI. Firefox is no longer execuate a binary file called directly to Hypertext on the local system. Why?

  I would rather not re - write the old of the IDE I have used for years but rather replace them with the style sheets for xml/html/web. Konqueror is running locally the binary with a launcher script. Firefox, Chrome, re-Konq, WebPositive and IE Explorer will not. If Firefox or SeaMonkey should run my binary that I could easily replace the old of the IDE and myself and my customers save a lot of time and money.

  Firefox does not execute binary files for security reasons. In other words, to prevent novice users to install malicious software.

• The binary file format

  With the help of LV2010.  I have a program that stores data in a binary file.  The file is a set of strings and floating point values.  I need to write another program in VB.NET that can save/read these files, so I need information on the actual file format of the data.  Is there a documentation which describes how the file is saved?  Thank you.

  Interesting. Usually, this question gets asked in the opposite direction with people trying to decode in a cluster.

  If you use the WriteToBinary function, your data are written as native data types in order to cluster in the binary file. Because you use a cluster, each string is being preceded by a length, which I believe is an I32.

  This is described in the help file for writing to a binary file. I think the people of thing travel length of string/array much however.

• Work of doesn´t of reading binary file on MCB2400 in LV2009 ARM embedded

  Hello

  I try to read a binary file from SD card on my MCB2400 with LV2009 Board built for the ARMS.

  But the result is always 0, if I use my VI on the MCB2400. If use the same VI on the PC, it works very well with the binary file.

  The
  access to the SD card on the works of MCB2400 in the other end, if I
  try to read a text file - it works without any problem.

  Y thre constraints for "reading a binary file" - node in Embedded in comparison to the same node on PC?

  I noticed that there is also a problem
  with the reading of the textfiles. If the sice of the file is approximately 100 bytes
  It doesn´t works, too. I understand can´t, because I read
  always one byte. And even if the implementation in Labview is so
  bad that it reads the total allways of the file in ram it sould work. The
  MCB2400 has 32 MB of RAM, so 100 bytes or even a few megabytes should
  work.

  But this doesn´t seems to be the problem for binary-problem. Because even a work of 50 bytes binary file doesn´t.

  Bye & thanks

  Amin

  I know that you have already solved this problem with a workaround, but I did some digging around in the source code to find the source of the problem and found the following:

  Currently, binary read/write primitives do not support the entry of "byte order".  Thus, you should always let this entry by default (or 0), which will use the native boutien of the target (or little endian for the target ARM).  If wire you one value other than the default, the primitive will be returns an error and does not perform a read/write.

  So, theoretically... If you return to the VI very original as your shift and delete the entry "byte order" on the binary file read, he must run a binary read little endian.

  This also brings up another point:

  If a primitive type is not what you expect, check the error output.

• "Read binary file" and efficiency

  For the first time I tried using important binary file on data files reading, and I see some real performance issues. To avoid any loss of data, I write the data as I received it acquisition of data 10 times per second. What I write is an array double 2D, 1000 x 2-4 channels data points. When reading in the file, I wish I could read it as a 3D array, all at the same time. This does not seem supported, so many times I do readings of 2D table and use a shift with table register building to assemble the table 3D that I really need. But it is incredibly slow! It seems that I can read only a few hundred of these 2D members per second.

  It has also occurred to me that the array of construction used in a shift register to continue to add on the table could be a quadratic time operation depending on how it is implemented. Continually and repeatedly allocating more larger and large blocks of memory and copy the table growing at every stage.

  I'm looking for suggestions on how to effectively store, read effectively and efficiently back up my data in table 3-d that I need. Maybe I could make your life easier if I had "Raw write" and "read the raw data" operations only the digits and not metadata.then I could write the file and read it back in any size of reading and writing songs I have if you please - and read it with other programs and more. But I don't see them in the menus.

  Suggestions?

  Ken

  
  

• Format for writing arrays to binary files

  I try to write to a binary file as a first step to understand how to work the stored formats.

  Currently, I have two vi, one writes a unique double in a file, and another writes a double 1 d table to a file.

  When I read these files in MATLAB, observing the correct format, I have successfully recover my double scalar single, but not the array of doubles.  The table comes from 10000 samples of a waveform of sin.  I observe that the sine wave output is correct via a waveform graph, and a graph shaped wave plugged into the values Y of the sinusoidal waveform.

  I use the same commands in MATLAB for both:

  FD = fopen ("output.bin', 'r', 'b');

  entry = fread (fd, inf, 'double-online double');

  fclose (FD);

  Attached are two variants of vi.

  By default, LabVIEW wrote the size of the array in the first bytes of the file. I'm not sure if MATLAB interprets this size information. Write to a binary file has an entry for controlling the economy of size information.  Try a wired False Boolean value for "precede the array or string of size?

  Lynn

• Strange behavior when reading binary file

  I'm reading from the binary data as flattened. The file was saved as a class of labview which contained the table of waveforms and other data. When I read the file with read binary file vi with class attached to the type of data the data are correct. But when I read the as flattened data something strange happened (see attached image). The two best shows correct data and two charts below shows the partially correct data. When you write code to read the flattened data I followed the instructions on http://zone.ni.com/reference/en-XX/help/371361H-01/lvconcepts/how_labview_stores_data_in_memory/ and http://zone.ni.com/reference/en-XX/help/371361H-01/lvconcepts/flattened_data/.

  The strange is that there is gap around 1.4 s (marked in red), but the samples before and after game.

  I don't know what I'm doing wrong.

  I have LV2011.

  Demand is also attached.

  

  

  Assuming that you your decoding of binary data is correct (that is, you have the data structure of the serialized class figured out) the problem is probably that you don't the read as binary data, you read in the text using the text file... Modify the read fucntion than binary.

• Adds data to the binary file as concatenated array

  Hello

  I have a problem that can has been discussed several times, but I don't have a clear answer.

  Normally I have devices that produce 2D image tables. I have send them to collection of loop with a queue and then index in the form of a 3D Board and in the end save the binary file.

  It works very well. But I'm starting to struggle with problems of memory, when the number of these images exceeds more than that. 2000.

  So I try to enjoy the fast SSD drive and record images in bulk (eg. 300) in binary file.

  In the diagram attached, where I am simulating the camera with some files before reading. The program works well, but when I try to open the new file in the secondary schema, I see only the first 300 images (in this case).

  I read on the forum, I have to adjust the number of like -1 in reading binary file and then I can read data from the cluster of tables. It is not very good for me, because I need to work with the data with Matlab and I would like to have the same format as before (for example table 3D - 320 x 240 x 4000). Is it possible to add 3D table to the existing as concatenated file?

  I hope it makes sense :-)

  Thank you

  Honza

  • Good to simulate the creation of the Image using a table of random numbers 2D!  Always good to model the real problem (e/s files) without "complicating details" (manipulation of the camera).
  • Good use of the producer/consumer in LT_Save.  Do you know the sentinels?  You only need a single queue, the queue of data, sending to a table of data for the consumer.  When the producer quits (because the stop button is pushed), it places an empty array (you can just right click on the entry for the item and choose "Create Constant").  In the consumer, when you dequeue, test to see if you have an empty array.  If you do, stop the loop of consumption and the output queue (since you know that the producer has already stopped and you have stopped, too).
  • I'm not sure what you're trying to do in the File_Read_3D routine, but I'll tell you 'it's fake  So, let's analyze the situation.  Somehow, your two routines form a producer/consumer 'pair' - LT_Save 'product' a file of tables 3D (for most of 300 pages, unless it's the grand finale of data) and file_read_3D "consume" them and "do something", still somewhat ill-defined.  Yes you pourrait (and perhaps should) merge these two routines in a unique "Simulator".  Here's what I mean:

  

  This is taken directly from your code.  I replaced the button 'stop' queue with code of Sentinel (which I won't), and added a ' tail ', Sim file, to simulate writing these data in a file (it also use a sentinel).

  Your existing code of producer puts unique 2D arrays in the queue of data.  This routine their fate and "builds" up to 300 of them at a time before 'doing something with them', in your code, writing to a file, here, this simulation by writing to a queue of 3D Sim file.  Let's look at the first 'easy' case, where we get all of the 300 items.  The loop For ends, turning a 3D Board composed of 300 paintings 2D, we simply enqueue in our Sim file, our simulated.  You may notice that there is an empty array? function (which, in this case, is never true, always False) whose value is reversed (to be always true) and connected to a conditional indexation Tunnel Terminal.  The reason for this strange logic will become clear in the next paragraph.

  Now consider what happens when you press the button stop then your left (not shown) producer.  As we use sentries, he places an empty 2D array.  Well, we dequeue it and detect it with the 'Empty table?' feature, which allows us to do three things: stop at the beginning of the loop, stop adding the empty table at the exit Tunnel of indexing using the conditional Terminal (empty array = True, Negate changes to False, then the empty table is not added to the range) , and it also cause all loop to exit.  What happens when get out us the whole loop?  Well, we're done with the queue of data, to set free us.  We know also that we queued last 'good' data in the queue of the Sim queue, so create us a Sentinel (empty 3D table) and queue for the file to-be-developed Sim consumer loop.

  Now, here is where you come from it.  Write this final consumer loop.  Should be pretty simple - you Dequeue, and if you don't have a table empty 3D, you do the following:

  • Your table consists of Images 2D N (up to 300).  In a single loop, extract you each image and do what you want to do with it (view, save to file, etc.).  Note that if you write a sub - VI, called "process an Image" which takes a 2D array and done something with it, you will be "declutter" your code by "in order to hide the details.
  • If you don't have you had an empty array, you simply exit the while loop and release the queue of the Sim file.

  OK, now translate this file.  You're offshore for a good start by writing your file with the size of the table headers, which means that if you read a file into a 3D chart, you will have a 3D Board (as you did in the consumer of the Sim file) and can perform the same treatment as above.  All you have to worry is the Sentinel - how do you know when you have reached the end of the file?  I'm sure you can understand this, if you do not already know...

  Bob Schor

  PS - you should know that the code snippet I posted is not 'properly' born both everything.  I pasted in fact about 6 versions here, as I continued to find errors that I wrote the description of yourself (like forgetting the function 'No' in the conditional terminal).  This illustrates the virtue of written Documentation-"slow you down", did you examine your code, and say you "Oops, I forgot to...» »

• How to determine the size of the binary file data set

  Hi all

  I write specific sets of data in table in a binary file, by adding each time so the file grows a set of data for each write operation.  I use the set file position function to make sure that I'm at the end of the file each time.

  When I read the file, I want to read only the last 25 data sets (or numbers).  To do this, I thought using the position set file to set the file position where it was 25 sets of data from the end.  Math easy, right?  Apparently not.

  Well, as I was collecting data file size as I began the initial tet run, I find the size of the file (using file order size and get number of bytes so) as the size increases the same amount every time.  My size and the format of my data being written is the same every time, a series of four numbers double precision.

  I get increments are as follows, after the first write - 44 bytes, after 2nd - 52 bytes, 3 - 52 bytes, bytes 44 4th, 5th - 52 bytes, 6 - 52 bytes, 7th - 44 bytes and it seems to continue this trend in the future.

  Why each write operation would be identical in size of bytes.  This means that my basic math for the determination of the poistion of correct file to read only the last 25 sets of data won't be easy, and if somewhere along the line after I've accumulated hundreds or thousands of data sets, what happens if the model changes.

  Any help on why this occurs or on a working method, all about the problem would be much appreciated.

  Thank you

  Doug