Size of the buffer of size/write DAQmx

Similar Questions

• DAQ Assistant don't update the buffer size to change the frequency

  Hi all

  I use DAQ Assistant inside a loop to write a signal in a module output best 9262 OR a cDAQ-9174.  I generate the signal with the express vi simulate Signal or with a simple loop using indexing.  The problem is that when I change the frequency, using the same sampling frequency, I have a different number of samples to write the cDAQ does not seem to update the size of the buffer, so no my signal gets written in.  The result is the first sine wave is nicely written, but each after that gradually get cut off on the edges.  I traced imput signal that I generate, so I know that it is generated with the right size and frequency of departure, what ever it is, still works, it is those more later in the loop who have the wrong size aparently buffer.  I tried to reset the cDAQ by adding a different DAQ Assistant at the end of the outer loop with the stop bit the true value, it makes me just the error "resource not available.

  Any ideas?

  I'm using LabVIEW Base development system new V12.0 32 bit.

  Thank you

  Matt

  Idea:

  Get rid of the DAQ assistant and use the DAQmx API.  The DAQ Assistant is there to support the limited functionality and base up a dirty experience and running quickly.  The report of the API offers more funcionallity and DAQmx property nodes allow greater flexibility.  DAQ Assistant is just too limited for your needs.  (you can't paint a masterpiece with crayons)

• data from the buffer before graph it and block size

  I hope you can help me with this situation because I was collapsed in this situation for two days and I think I see the light in the short time and time is a scarce resource.

  I want to use a NI DaqCard-HAVE-16XE-50 (20KS/sec accordig to the specifications). For data acquired by DasyLab, I use OPC DA system but when I try to get a graphic from the signal I get ugly results.

  I guess the problem is that the PC is not powerful to generate a graph in real time, is if there is a block to save the data, then graph the data without using "write data" block to avoid to write data on the disk?

  Another cause of the problem, it might be an incorrect value for adjusting the size of block, but in my piont of view with the 10 kHz and 4096 block size is more than necessary to acquire a signal of 26 [Hz] (showing the photo). If I reduce the size of the block to 1 signal showing in the graph is a constant in the first acquisition value. Why might this situation?

  Thanks in advance for your answers,

  You don't want to use OPC DA for a device installed with the material. OPC DA is designed for industrial devices low speed, not for cards installed 20 kHz!

  Rerun setup of DASYLab and select the OR-DAQ driver, deselect the NOR-DAQmx driver.

  You must use the analog input OR-DAQ module for talking directly to the camera. You will get the full speed of the device, and the buffering is managed properly.

  I have this card somewhere in a box, and when I used it, it worked perfectly with the NOR-DAQ driver.

• How to increase the size of the buffer

  Hi, I would like to ask how can I increase the size of the buffer?

  My problem is that the generation cannot be started,

  because the buffer size is too small by the way I use DAQ Assistant.

  Choose the size of the buffer: 1

  Minimum required buffer size: 2

  so, how do I solve it?

  Thank you

  Chris

  Hello Chris, can I ask what material you use. Currently the DAQ Assistant in your code example is configured to run continuous Acquisition and thus expects a type of dynamic data. This can be seen by the small red spot known as a point of stress and is shown when LabVIEW must convert the data to a different type. There are two options you can try to solve this problem.

  (1) change the type of Acquisition "(on request) 1 sample" in the DAQ Assistant, he will write your input value for the cDAQ with each iteration of the while loop

  (2) change of data entry strikes at a waveform

  Here are some articles that you might find useful http://zone.ni.com/devzone/cda/tut/p/id/5438

  Hope this is useful

  Philippe

  

• What are the data size of the buffer on PX1394E - 3 50

  Hello

  I bought this drive a few days ago and I'm a little confused on the
  the size of the data buffer. The box indicates 16 MB, Toshiba web page says 8 MB, etc...

  Nobody knows, what are the data buffer size of this model?
  Is there a SW or the request to meet with whom?

  BTW, great car, fast, noise, however, extremely when it comes to finding large files.

  Thank you
  Francisco

  Hello

  I have lurked around a bit and it seems that your drive has buffer of 16 MB that is absolutely definitely sure. To check the details of your computer, you can use the tool "Sisoft Sandra". You can download [url href = http://www.sisoftware.net/index.html?dir=&location=downandbuy&langx=en&a=] here [/ URL].

  After download, just install it and you will get all information about your computer, as the size of the buffer of your external hard drive.

  Welcome them

• Range the range must belong to the size of the buffer.

  Hello

  I'm pretty stumped on this problem. I have a chart with a picture of Chartcollections. The tables are filled in at the same time. Sometimes, quite randomly, I get this exception. In this case, I had three parcels posted:

  System.ArgumentOutOfRangeException was unhandled
  HResult =-2146233086
  Message = range slice must belong to the size of the buffer.
  Parameter name: length
  Real value was 3.
  Source = NationalInstruments.Common
  ParamName = length
  StackTrace:
  to NationalInstruments.Restricted.Guard'1.Satisfies (Boolean condition, Func 4 exceptionCreator, String format, Object [] args)
  NationalInstruments.Restricted.NIValidation.IsInRange [T] (1 keep, Boolean isInRange, format String, Object [] args)
  to NationalInstruments.DataInfrastructure.Primitives.RawDataStore'1.Slice (Int32 startIndex, Int32 length)
  to NationalInstruments.DataInfrastructure.Buffer'1.Slice (Int32 startIndex, Int32, Func 2 traitFilter length)
  to NationalInstruments.DataInfrastructure.Buffer'1.NationalInstruments.DataInfrastructure.IBuffer.Slice (Int32 startIndex, Int32 length)
  at NationalInstruments.Controls.Internal.DefaultAdjusterStep.a (IDictionary 2 A_0)
  at NationalInstruments.Controls.Internal.DefaultAdjusterStep.c (IDictionary 2 A_0)
  at NationalInstruments.Controls.Internal.DefaultPipelineDataProcessor.a (DefaultDataItemDescription [] A_0)
  at NationalInstruments.Controls.Internal.DefaultPipelineDataProcessor.a)
  at System.Windows.Threading.ExceptionWrapper.InternalRealCall (Int32 numArgs, delegate callback, object args)
  to the millisecond. Internal.Threading.ExceptionFilterHelper.TryCatchWhen (Object source, method Delegate, Object args, Int32 numArgs, delegate catchHandler)
  at System.Windows.Threading.DispatcherOperation.InvokeImpl)
  at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext (Object state)
  at System.Threading.ExecutionContext.RunInternal (ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
  at System.Threading.ExecutionContext.Run (ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
  at System.Threading.ExecutionContext.Run (ExecutionContext executionContext, ContextCallback callback, Object state)
  at System.Windows.Threading.DispatcherOperation.Invoke)
  at System.Windows.Threading.Dispatcher.ProcessQueue)
  at System.Windows.Threading.Dispatcher.WndProcHook (IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean & handled)
  to the millisecond. Win32.HwndWrapper.WndProc (IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean & handled)
  to the millisecond. Win32.HwndSubclass.DispatcherCallbackOperation (Object o)
  at System.Windows.Threading.ExceptionWrapper.InternalRealCall (Int32 numArgs, delegate callback, object args)
  to the millisecond. Internal.Threading.ExceptionFilterHelper.TryCatchWhen (Object source, method Delegate, Object args, Int32 numArgs, delegate catchHandler)
  to System.Windows.Threading.Dispatcher.LegacyInvokeImpl (priority DispatcherPriority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
  to the millisecond. Win32.HwndSubclass.SubclassWndProc (IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
  to the millisecond. Win32.UnsafeNativeMethods.DispatchMessage (MSG & msg)
  at System.Windows.Threading.Dispatcher.PushFrameImpl (DispatcherFrame frame)
  at System.Windows.Threading.Dispatcher.PushFrame (DispatcherFrame frame)
  at System.Windows.Threading.Dispatcher.Run)
  at System.Windows.Application.RunDispatcher(Object ignore)
  System.Windows.Application.RunInternal (window)
  System.Windows.Application.Run (window)
  at System.Windows.Application.Run)
  at MyProject.FinalTest.Specific.GUI.App.Main (c:\Sandbox\Specific2\MyProject.FinalTest.Specific.GUI\obj\Debug\App.g.cs:line 0)
  at System.AppDomain._nExecuteAssembly (RuntimeAssembly assembly, String [] args)
  at System.AppDomain.ExecuteAssembly (String assemblyFile, Evidence assemblySecurity, String [] args)
  at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly)
  at System.Threading.ThreadHelper.ThreadStart_Context (Object state)
  at System.Threading.ExecutionContext.RunInternal (ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
  at System.Threading.ExecutionContext.Run (ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
  at System.Threading.ExecutionContext.Run (ExecutionContext executionContext, ContextCallback callback, Object state)
  at System.Threading.ThreadHelper.ThreadStart)
  InnerException:

  I don't know even where to start looking! Can someone please give me some advice? Thank you!

  I found the problem!

  I had a timer by calling the method, which has updated the plots of a queue. If there is too many signals, emptying of the queue can take longer than the next call timer, and two threads try to access the graphics paralel. I know that set the idle timer for the queue reading and turn it on after and looks of problem solved!

  Thanks for the idea of bouncing, that's the direction I had to start looking!

• Guidelines to set the buffer size?

  Are there articles or messages that describe the basic guidelines for choosing the sizes of memory buffer to use when acquiring data?

  Are there specific problems that occur when the buffers are too large or too small?

  Thank you

  Dave

  The buffer must be large enough to handle the data acquired during the long interval between reading th book.

  Too small and encounter you problems if you do not read your data fast enough.

  Too much and you lose memory.

  My personal recommendation is "close your eyes and imagine the user trying to open a huge Excel spreadsheet while the application is running" - However for long, I suspect that the PC will have to open the file will dictate (based on the sample rate) what is the minimum size. In the old days, I would just double this figure. These days, I can use a 5 fudge factor.

  Ben

• You want to know the size of the buffer on the mk3 5...

  ... and/or the number of raw files full resolution, it may contain. I was wondering if I used to pull a maximum of six bursts of shooting, writing the same question speed card?

  dbltapp wrote:

  ... and/or the number of raw files full resolution, it may contain. I was wondering if I used to pull a maximum of six bursts of shooting, writing the same question speed card?

  It does not matter to 6 shots.

  See: http://www.learn.usa.canon.com/resources/articles/2012/eos_understanding_burst_rates.htmlp

  The conservative estimate of the size of the buffer (in RAW mode) is that the buffer will hold about 13 shots until the camera is to wait for the data to be written in order to clear enough space for another buffer.   I actually tested it with my 5 d III and have found that, in practice, the number is somewhat higher - having about 18 shots before he slowed because of the limitations of the buffer.

• The buffer is smaller than the specified size.

  Has done a session of webniar via GoToWebinar, that has been saved as a Windows Media audio/video file. It has been downloaded to my desktop without problem, and the original file plays on Windows Media player. I need to send the session recorded with colleagues across the Canada. It's a big file to 55.5 MB, I usually use YouSendIt.com and have done so successfully with the same type of files in the recent past. This time, when I send the file and download it via YouSendIt, it records on my desk in a 55.5 MB file with the correct file name, but when I try to open this file, I get an error message: "the buffer is smaller than the specified size. Any ideas on what may be the problem. How this can be solved?

  Best regards

  Deborah

  I do not have the fix for YouSendIt, but it may be worth trying to
  Download your file on SendSpace... then just send download
  link to your recipients and they can download the file to their
  own convenience.

  "SendSpace.
  http://www.sendspace.com/

  It's very simple... of the SendSpace site steps
  are just what you have to do.

  On the left, click on the Browse button and it will open a window which
  allows you to access the files on your hard drive.

  Go to your video file and select it.

  On the left, click on the download button.

  When the download link appears... left click on the copy button.

  Share this link with your recipients.

• How to set the size of the buffer of interruption UDP XP 64-bit

  I need to increase the size of the incoming buffer Windows UDP interruption and also fine-tune Windows for optimal UDP performance.

  (It is the buffer used by the Windows service interrupt routine to handle incoming UDP, not setsocket for the application buffer).

  We have a real-time system, Windows is the only computer connected to the chassis generating UDP datagrams to about 800 Mbps.

  Hi _Doug Bell.
   

  Your question of Windows is more complex than what is generally answered in the Microsoft Answers forums. It is better suited for the IT Pro TechNet public.

  Please post your question in the Forums Pro Windows XP IT

• Question of size for the buffer DAQmxRegisterEveryNSamplesEvent

  Hello? I'm testing the DAQmxRegisterEveryNSamplesEvent function, but it returns an error message. I put the size of the sample 7200.

  

  

  Error message is

  

  Providing the function set buffer size? Where do I get 100 000 buffer size in this code?

  OK, I thought about it. This is DAQmx_Val_FiniteSamps property of DAQmxCfgSampClkTiming. You must use the buffer size specified in the DAQmx_Val_FiniteSamps property.

  Thank you

• Current playback position exceeds the buffer size? VB6 with NIDAQmx 9

  I have an application written in VB6 that does HAVE and AO, with both using the Ctr0 internal as the clock to check that they are in sync.   It seems to work very well.  I use a USB-6212 and a recent version of NIDAQmx.

  I am tracking the current playback Position by calling DAQmxGetReadCurrReadPos_VB6 in the EveryNCallback routine.

  Strangely, the value for each call correctly increases the number of returned samples (for example, 128), but instead of round package when it reaches the upper limit of the buffer (for example 16 * 128) it keeps growing to infinity.  No error is reported by the call to DAQmxGetReadCurrReadPos_VB6 or anything else.

  Am I misunderstood something?  This function seems to be to just return the total number of samples read, not the position in the buffer.

  What I expect the value of the current to be playback Position:

  128, 256, 384, etc..  the limit of the buffer for example 16 x 128 = 2048 how he could start over at 1 (or zero depending on the way which you set up your berries).

  Van

  Hi afmstm,

  The behavior you're seeing is indeed good, and I agree that the description that it is misleading.  The current description says:

  "In the samples per channel, shows the current position in the.
  buffer.

  The description should be interpreted as:

  "In the samples per channel shows the current position the acquisition."

  So yes, for a relative position within your stamp, you must perform a modulo operation.

  That being said, it's not the same thing as 'total number of readings/a. Since the beginning of the program' as you say.  This would be the attribute Total of samples by acquired chain .  It is rarely a chance where these two alignment attributes.  For example, to read N samples successfully the following must be satisfied:

     Total samples by acquired channel - current read Position = N

  Another distinction is that you, the user can change the current Position of playback using the properties relative to and Offset .  By default you will read from the current playback Position , which creates the behavior your described.

  I know it can be confusing, but this level of manipulation of streaming is a very advanced concept of DAQmx.  Let me know if this raises questions or concerns more!

• Doubt about the writer of the buffer

  Friends, according to the docs, DBWR written as below: -.
  
  "The process of writer (DBWn) of database written periodically cold, dirty buffers to disk. DBWn writes tampons in the following circumstances:
  
  A server process not found own buffers to read the new blocks in the database buffer cache.
  
  As the pads are dirty, the number of free buffers decreases. If the number is less than an internal threshold and so clean buffers are needed, then the process server report DBWn to write.
  
  The database uses the LRU to determine what dirty buffers to write. When stamps Sales reach the cold end of the LRU, the database moves off the LRU to a write queue. DBWn wrote buffers in the queue on the disc, using if possible written multiblock. This mechanism prevents the end of the LRU get clogged with dirty buffers and allows own buffers available to be reused.
  
  The database must move the control point, which is the position in the thread of Redo from which must begin the recovery instance.
  
  Storage spaces are turned into read-only or offline status.
  "
  
  Can someone explain the 4th scenario is to say "" you database must move the control point, which is the position in the thread to which instance again must start recovery. "." whereby DBWR write in data files?
  
  Thanks in advance.

  918868 wrote:
  Why the database does advance the checkpoint? Aman said in the last post that Oracle has not advanced at the checkpoint because of the SCN generation/updates is for other reasons? What is the relationship to this buffer written in advance of the checkpoint?

  There are many different types of "checkpoints" (see http://jonathanlewis.wordpress.com/2007/04/12/log-file-switch/) the two best-known are the point of log file picker control and additional control point.

  The checkpoint log file switch (which I think is named the Checkpoin wire) is the one who translates written Oracle buffers of data in the data files if their first vector of change roll forward is saved in a file journal; This point of control translates into an update to each data file header AFTER the checkpoint is complete and that the redo log file can be overwritten.

  The additional control point is shot every three seconds by DBWR poster himself tells dbwr to recalculate a new target YVERT and redo block address (based on things like the MTTR, the fast_start_target, the log_checkpoint_interval or the log_checkpoint_timeout) and write to the file and the data blocks that have first were changed before SNA; the SNA is only recorded in the control file.

  The first type of control point allows Oracle to choose the right file to log to start recovering from the second tells it where to start in the file.

  Concerning
  Jonathan Lewis

• all samples n transferred from the buffer

  Hi all

  I have a question for every N samples transferred DAQmx event buffer. By looking at the description and the very limited DevZones and KBs on this one, I am inclined to believe that the name is perfectly descriptive of what must be his behavior (i.e. all samples N transferred from the PC buffer in the DAQmx FIFO, it should report an event). However, when I put it into practice in an example, either I have something misconfigured (wouldn't be the first time) or I have a basic misunderstanding of the event itself or how DAQmx puts in buffer work with regeneration (certainly wouldn't be the first time).

  In my example, I went out 10 samples from k to 1 k rate - so 10 seconds of data. I recorded for every N samples transferred from the event of the buffer with a 2000 sampleInterval. I changed my status of application of transfer of data within the embedded memory in full with the hope that it will permanently fill my buffer with samples regenerated (from this link ). My hope would be that after 2000 samples had been taken out by the device (e.g., take the 2 seconds) 2000 fewer items in the DMA FIFO, it would have yielded 2000 samples of the PC for the FIFO DMA buffer and so the event fires. In practice it is... not to do so. I have a counter on the event that shows it fires once 752 almost immediately, then lights up regularly after that in spurts of 4 or 5. I am at a loss.

  Could someone please shed some light on this for me - both on my misunderstanding of what I'm supposed to be to see if this is the case and also explain why I see what I see now?

  LV 2013 (32 bit)
  9.8.0f3 DAQmx
  Network of the cDAQ chassis: 9184
  cDAQ module: 9264

  Thank you

  There is a large (unspecced, but the order of several MB) buffer on the 9184.  He came several times on the forum, here a link to an another discussion about this.  Quote me:

  Unfortunately, I don't know the size of this buffer on the 9184 on the top of my head and I don't think it's in the specifications (the buffer is also shared between multiple tasks).  This is not the same as the sample of 127 by buffer slot AO which is present on all chassis cDAQ - controller chassis ethernet / wireless contains an additional buffer which is not really appropriate I can say in published specifications (apparently it's 12 MB on the cDAQ wireless chassis).

  The large number of events that are triggered when you start the task is the buffer is filled at startup (if the on-board buffer is almost full, the driver will send more data — you end up with several periods of your waveform output in the built-in buffer memory).  So in your case, 752 events * 2000 samples/event * 2 bytes per sample = ~ 3 MB of buffer memory allocated to your task AO.  I guess that sounds reasonable (again would really a spec or KB of...) I don't know how the size of the buffer is selected).

  The grouping of events is due to data sent in packages to improve efficiency because there is above with each transfer.

  The large buffer and the consolidation of the data are used optimizations by NOR to improve flow continuously, but can have some strange side effects as you saw.  I might have a few suggestions if you describe what it is you need to do.

  Best regards

• Problem with the series of read/write

  Hi all

  I don't know if this belongs here or on one of the guidance material, but I thought I would start here.

  I have two devices which I am currently trying to contact via the serial ports on a PXI chassis in real time.  In both cases, I series of software that seems to work fine when I use the serial port on the controller (for example, COM1).  Now, I have two cards that I used two different systems to talk to these devices - 8430/2 and 8430/4.  In both cases, when I use these cards, it seems I have periodic in response by devices delays when you use the same code that I use when talking through the serial port of the controller (i.e., I get some downtime when trying to read code error-1073807339).  I tried to Exchange cards with spare parts, but I have the same problem.  I can handle the delays to retransmit the command, but this destroys ultimately the determinism of the system given that the delay may create a pause of up to 2 seconds.  I tried to change the size of the buffer, but I seem to have the same problem.  Does anyone have any ideas as to what could happen?

  Cheers, Matt

  Thank you, Luis.  Indeed, one of the errors being thrown was a timeout error (the other was thrown by one of the devices indicating that he did not understand the command sent).  However, the problem wasn't that I was getting a timeout, but rather that I was getting an error on one platform and not on another.  But it seems that I solved my problem - I simply set the I/O VISA Write mode to synchronous and this seemed to solve the problem I had.

  Cheers, Matt