TDMS NI_DiskCacheSize property

Similar Questions

• 'Length' of reading TDMS channel property

  Hello

  I wonder if someone could point me the right direction please. I could not seem to be reading "Length" property of TDMS channels using vi «PDM get properties» I read it easily. In the worst case I might eventually write a 'Channel Length' property at the time of closing vi after dividing the total duration of sampling frequency and its reading back! I hope that there is a very good way to do this?

  k waris wrote:

  Hello

  I wonder if someone could point me the right direction please. I could not seem to be reading "Length" property of TDMS channels using vi «PDM get properties» I read it easily. In the worst case I might eventually write a 'Channel Length' property at the time of closing vi after dividing the total duration of sampling frequency and its reading back! I hope that there is a very good way to do this?

  It would be useful to see your code. He did to wire a digital constant to the type of input data? When left unwired it looks like a string, and since it is a numeric value it returns nothing.

  Also, make sure you have the name of appropriate property for the file EXAMPLE.tdms (example of file supplied with Diadem) in Diadem property Name length is displayed but when using TDMS get properties, you can see that the name of this property is actually NIChannelLength.

  Ben64

• DisplayName property

  Hello

  A small question about the properties...

  (1) I noticed that if I add a property with the name 'Unit' in LabVIEW to a TDMS file I can't delete it in tiara. It seems that it confuses it with the reservation of title "unit_string" (which has the 'Unit' DisplayName property) - I think it is a bug and not the intended behavior?

  (2) why is the property of "DisplayName" of a custom property is read-only?

  Kind regards

  Steve.

  Hi St3ve,

  If you go create TDMS files in LabVIEW and view them in DIAdem, THANKS to write unit information to the property 'Unit_String' using "TDMS property Set.vi" LabVIEW - this will avoid any confusion and frustration.

  It looks like the behavior of a 'Unit' property in the data portal is buggy since the handling in version 11.0 DIAdem unit, I had not noticed this before.  What version of DIAdem do you use?  The message box talk not being is not able to deal with information of the unit with the property 'Unit' seems intentional, but you should be able to delete the property interactively, which fails in tiara 2011.

  You can use the TOC header object to remove the unwanted a TDM file property, but as the so-called Yongqing TDMS file format does not support delete a property, making it much more difficult that you can't remove it from the data portal.  You can save the TDMS file in a TOC file, remove the unit, then save it to a TDMS file...

  Set TdmHdrObj = DataFileHeaderAccess ("C:\Example.tdm", "CT", False)

  Call TdmHdrObj.ChnPropDel ("[1] / [1] ', 'Unit'")

  Call TdmHdrObj.Save

  Brad Turpin

  Tiara Product Support Engineer

  National Instruments

• Integrated Properies of TDMS files

  I found a problem with CVI 2010 SP1 built-in properties of a PDM file reading.

  Functions:

  • TDMS_GetFileStringPropertyLength with property TDMS_FILE_NAME
  • TDMS_GetFileProperty with property TDMS_FILE_NAME
  • TDMS_GetChannelGroupStringPropertyLength with property TDMS_CHANNELGROUP_DESCRIPTION

  error-6629 TDMS_PropertyDoesNotExist if these properties exist but are an empty string!

  I think that this error is returned only if the property is not really exist, not if it is an empty string.

  I have seen this with example TdmsReader provided with one of my TDMS files.

  Hey Vix,

  The file was created in CVI or LabVIEW? When you create the TDMS file in CVI, the name property is required or the TDMS_CreateFileEx returns an error. However, the TDMS vi open (with the create option) does not require the property name to set. So if the file has been created in LV, so unless the name property has been specifically created, then there is no. In the Excel plugin, if the name property does not exist, it uses by default the name of the file (the name property does not necessarily match file name).

  Since you have access to LV, you can simply add this property yourself with vi TDMS Set Property. It can also be a good habit of always set the 4 standard properties when creating files in LV TDMS

• Channel playback TDMS property

  Hello

  I managed to read the property of length of channel DDHN at the level of channel using the name of the property "NI_ChannelLength". Although in the file, it is called "length".

  I wonder if there's a mysterious name for the property of "Strings" which gives the number of channels in each group at the level of the group.

  In the worst case, I might have to write and then read back. But I wanted to keep TDMS file clean and not double field that already exists!

  Any comments?

  See you soon

  Waris K

  Only use the TDMS list content and provide the name of the group.  It returns the names (and therefor the number) of channels in this group.

• How ENUM as TDMS property of reading / writing?

  LV2103, Win7

  Old road to LabVIEW, new brand tiara.

  I need to convert a structure of arbitrary complexity in properties, suitable for writing in a PDM file, in such a way that they are recoverable and (hopefully) to be readable by humans, such as whn, the file is loaded in tiara.

  I have most of it works fine, but I have trouble with ENUMs.

  An ENUM can be converted to a VARIANT very well, but that the alternative of writing to a file produced error-68007.

  A simple test shows this:

  

  The encoding process is quite simple - given a generic control Ref, just look at its CLASS ID.

  If the ID is one of those basic, just get its value in as a variant and add the berries of NAME and OWNERSHIP:

  

  If the element is a CLUSTER, then the controls that it contains and make them one by one:

  

  If the control is a TABLE, it is a little more difficult.  Since there is no way to obtain a reference to an arbitrary reference, you must use a reference to an item that you have.  To use it, you must show one and the same element.  This code is that, while restoring the original notice:

  

  HOWEVER

  ENUM, as I said earlier, converted to VARIANT very well, but TDMS will not accept it.

  Here's a technique that works, sort of:

  

  By converting the enum in an I32, you get the digital value from its current location and can put that into a Variant.

  During playback, the digital value will set the ENUM control correctly, so that's good.

  The problem is in the tiara, the property will look like:

  Whatever_Engine_Cycle 2

  Even if this is true and read back OK, he doesn't tell the user what kind of cycle is.

  The point of ENUMS was to put names to specific numbers.

  I tried to convert the variant to a STRING instead of an I32, but occurs 1057 (IIRC): "cannot convert a Variant to the specified type.

  A similar problem exists for controls TEXT RING - although they will go through the process, without error, what appears is a number.

  Any ideas to make the DIAdem display the string value of the ENUM, instead of a number?

  The error that says no "recognized by this version of LabVIEW" - is LV2015 to be more smart about it?

  Nice post clear! We will try for an elegant solution.  I think you're halfway there!

  You know the ID of class its an enum so get the credits of enum

  

  This may not work with the type defs, I leave that to you.  Rings and rings of text can be manipulated simillar

  Edit: Of course move up the chain to the variant

• TDM file query property names

  I use the TDM files to save data from the trial.  At the file level, I am inserting a number of custom property labels (using the Property.vi defined in the IO file-> storage-> advanced storage pallet).

  Is it possible to query the names of these properties once the file has been written?  For example, if I put in a custom property "TestLocation", is there a way I can find the name of this property afterwards, so I can read the value?

  JoeG

  Hey Joe,

  Please try the attached VI for the names of the custom properties.

  Best regards

  Mavis

• TDMS wf_start_time with milliseconds

  How can I include information millisecond of time of waveform information in my TDMS file?

  Resemble my timestamps: 17/10/2016 08:59:34.000 AM

  Hi sez!

  The DAQmx property do not support to set the properties in the PDM log file.

  

  The only thing you can do is create a file and write the start time property in this file. The DAQmx driver opens this file again and log data in the file.

  

  Basically, you can do it, but I prefer the solution of low level with the TDMS screws indicated in the post before.

  Best regards

  Wolfgang

• PDM: Add DateTime vs PrecisionDateTime property

  I'm back with another question about the API of PDM .NET.

  What do you expect when you add a property to a DateTime value to a PDM file, then add another property with the same value converted to a value of PrecisionDateTime? The two must be kept as i64 + u64 bits according to the Structure of the TDMS File Format.

  var someDate = new DateTime (635757120000000000L, DateTimeKind.Local);
  
  using (var file = new TdmsFile (@"C:\Temp\ts.tdms ', TdmsFileOptions() ')) new
  
  {
  
      file. AddProperty ("_ts0", TdmsPropertyDataType.DateTime, someDate);
  
      file. AddProperty ("_ts1", TdmsPropertyDataType.DateTime, PrecisionDateTime.FromDateTime (someDate));
  
  }

  In binary, the seconds total i64 are equal, but the part of fraction u64 to the first property is 0 x 0000800000000000.

  Then when I read the first property, I get a difference in DateTime 76 ticks which is equal to 7.6 µs.

  It's the 'precision' I get at the price of 128-bit?

  Beste regards,

  Jonas

  HI jonas,.

  Sorry it took awhile. We managed to do work and could reproduce the behavior. I forwarded your it.

  Thank you for the information system.

  Best,

  Anna

• TDMS & Diadem best practices: what happens if my mark has breaks/cuts?

  I created a LV2011 datalogging application that stores a lot of data to TDMS files.  The basic architecture is like this:

  Each channel has these properties:

  To = start time

  DT = sampling interval

  Channel values:

  Table 1 d of the DBL values

  After the start of datalogging, I still just by adding the string values.  And if the size of the file the PDM goes beyond 1 GB, I create a new file and try again.  The application runs continuously for days/weeks, so I get a lot of TDMS files.

  It works very well.  But now I need to change my system to allow the acquisition of data for pause/resume.  In other words, there will be breaks in the signal (probably from 30 seconds to 10 minutes).  I had originally considered two values for each point of registration as a XY Chart (value & timestamp) data.  But I am opposed to this principal in because according to me, it fills your hard drive unnecessarily (twice us much disk footprint for the same data?).

  Also, I've never used a tiara, but I want to ensure that my data can be easily opened and analyzed using DIAdem.

  My question: are there some best practices for the storage of signals that break/break like that?  I would just start a new record with a new time of departure (To) and tiara somehow "bind" these signals... for example, I know that it is a continuation of the same signal.

  Of course, I should install Diadem and play with him.  But I thought I would ask the experts on best practices, first of all, as I have no knowledge of DIAdem.

  Hi josborne;

  Do you plan to create a new PDM file whenever the acquisition stops and starts, or you were missing fewer sections store multiple power the same TDMS file?  The best way to manage the shift of date / time is to store a waveform per channel per section of power and use the channel property who hails from waveform TDMS data - if you are wiring table of orange floating point or a waveform Brown to the TDMS Write.vi "wf_start_time".  Tiara 2011 has the ability to easily access the time offset when it is stored in this property of channel (assuming that it is stored as a date/time and not as a DBL or a string).  If you have only one section of power by PDM file, I would certainly also add a 'DateTime' property at the file level.  If you want to store several sections of power in a single file, PDM, I would recommend using a separate group for each section of power.  Make sure that you store the following properties of the string in the TDMS file if you want information to flow naturally to DIAdem:

  'wf_xname '.
  
  'wf_xunit_string '.
  
  'wf_start_time '.
  
  'wf_start_offset '.
  
  'wf_increment '.

  Brad Turpin

  Tiara Product Support Engineer

  National Instruments

• datafinder results date of inaccessible property via script

  Hello

  I'm running into a strange question. I need to programmatically access the date of the change of the results of my research. This property is visible in the browser window. When I make a list of all the properties of the items in the results of my research datafinder, property appears so. When I query the datatpe, name and other attributes of this property, I get a response. But when I try to access its value, I get an error telling me that this property or method is not supported by the object. What is even more strange is that I'm not running into this problem with other properties. It seems to happen with the variety of date properties. I am very confused

  Thabks in advance for the help.

  Here we have a difference between the Datafinder API and the API of the internal root.

  In the case of DataFinder, date values are returned as usiTimeDispObject.

  Option Explicit
  
  Dim oMyDataFinder, oMyQuery, oMyResults
  
  Set oMyDataFinder = Navigator.ConnectDataFinder ("My DataFinder")
  
  Set oMyQuery = oMyDataFinder.CreateQuery (eTextQuery)
  
  oMyQuery.Text = "example.tdm".
  
  Call oMyDataFinder.Search (oMyQuery)
  
  protected rootElem: set rootElem = oMyDataFinder.Results.Item (1)
  Dim oMyProp, txt
  
  txt = «»
  
  For each oMyProp in rootElem.Properties
  
    Dim propVal
  
    If DataTypeDate = oMyProp.DataType then
  
      propVal = oMyProp.Value.VariantDate
  
    on the other
  
      propVal = oMyProp.Value
  
    end if
  
    txt = txt & oMyProp.Name & ":" & propVal & + "\n"
  
  Next
  
  MsgBox txt

  There is no indirection for portal DIAdem.

  Option Explicit
  
  Dim oMyProp, txt
  
  txt = «»
  
  For each oMyProp in data.root.Properties
  
    Dim propVal
  
    propVal = oMyProp.Value
  
    txt = txt & oMyProp.Name & ":" & propVal & + "\n"
  
  Next
  
  MsgBox txt

• Problem in ANSI C for example - error TDMS-ContAcq-IntClk 200877

  Hello

  I tried the examples in the 'ANSI C examples' folder and ran into a snag with the example in:

  "" \DAQmx ANSI C\Analog In\Measure Voltage\Acq TDMS-Cont-Int Clk".

  When I run it as it is, I get the following error:

  DAQmx error: requested each interval of N samples event is not supported for the given the mechanism of transfer of data and the buffer size. To keep the DMA or USB in bulk as the data transfer mechanism, change the size of the buffer or the interval of event Every N samples so the size of the buffer is a multipleof even interval event Every N samples. To keep the same each event interval of N samples and the size of the buffer, modify the mechanism for transfer of data interruptions if taken in charge. Property: DAQmx_Every N samples CQI event IntervalRequested value buffer: size 1000Buffer: 12288Task name: _unnamedTask<0>State :-200877End of the program Code, press the Enter key to exit
  
  

  As I was typing this, I did a quick test. I tried to comment this line in the code:

  / / *	/ / PDM DAQmx Configure Code	/ * /	DAQmxErrChk (DAQmxConfigureLogging(taskHandle,"C:\\example.tdms",DAQmx_Val_LogAndRead,"GroupName",DAQmx_Val_OpenOrCreate));)
  

  and it worked, as I suspected.

  My gut feeling is that the DAQmxConfigureLogging function expects a block of 12 288 bytes, and in the rest of the code, the number of samples is set to 1000, with a sampling frequency of 10000.

  In any case, I fixed it by changing from 1000 to 1024 (1024 because * 12 = 12288) anywhere in the code, so solve the original problem.

  I don't have a few new questions now:

  1. is this an error in the example, or am I missing something?

  2. How do you change the default size 12288 DAQmxConfigureLogging() waiting for let say 5000?

  Thank you.

  Hall

  Hey Bob,

  In fact, it is a bug with this example.  It comes with the value 1000 for the wrong sampling interval since it is an example of logging.  When logging is enabled on a task, default buffer sizes are slightly different from the default values without connecting.  This is because the default buffer sizes are powers of 10, while hard drives prefer to powers of 2.  It is a maneuver of performance as we listen to disc directly from the buffer DAQmx.

  I think you should be able to use 1024 as your sampling instead of 1000 interval in this example.  In this example, the default value will change so that it is not immediately error (Corrective Action Request #177199).

• Name of the TDMS file for use in Diadem report

  I received a large number of TDMS files collected with Signal Express 2014 and all of these files are called voltage.tdms in several subfolders, when I opened a sample of these files in Diadem I see that they have unique names in the field title properties voltage.tdms and so I would like to use this in a report model that I created. What I failed to find it is an easy way to capture the value of this title and put it in my report model, there is a variable called ChnDataFileName name, but it gives me "voltage.tdms", I don't see any of these variables to extract the field title, anyone know how to access this field?

  Hi ADobson

  The easiest way is to drag & give up the property from the data of the report portal. Then you will get something like

  Title: @Data.Root.Properties ("title"). Value @.

  Hope that helps

  Winfried

• Creation Waveform TDMS file using the functions DDC_ in C 6.0?

  I'm trying to implement an export written in C 6.0. I can make the TDMS files using the DDC_ controls without any problem. But I can't understand how waveform TDMS files. I thought that if I added properties wf_ I should be able to define the waveform = Yes. But it seems to be more complicated than that.

  Here's what I work until now... (with the exception of the error handling to make it easier to see)

  DDC_CreateFile (sDestFileName, "TDMS", gszinfoline1, gszinfoline2, gszinfoline3, gszinfoline4, & hOutputFile);

  DDC_AddChannelGroup (hOutputFile, szGROUP_NAME, szGROUP_DESC, & hgroup)

  DDC_CreateChannelGroupPropertyTimestampComponents (hgroup,
  szCHANNEL_NAME,
  year (unsigned int),
  months (unsigned int).
  days (unsigned int).
  hours (unsigned int).
  minutes (unsigned int).
  wholeseconds (unsigned int),
  (double) fractionseconds);

  DDC_AddChannel (hgroup, DDC_Double, szCHANNEL_NAME, szCHANNEL_DESC, szCHANNEL_UNITS, & lphchannel);

  DDC_CreateChannelProperty (lphchannel, "wf_increment", DDC_Double, dInterval);
  DDC_CreateChannelProperty (lphchannel, 'wf_xname', DDC_String, 'Time');
  DDC_CreateChannelProperty (lphchannel, "wf_xunit_string", DDC_String, "s");
  DDC_CreateChannelProperty (lphchannel, "wf_start_offset", DDC_Double, 0,0);

  Any suggestions? (Details of this aid are intended for LV or completely absent)

  Thank you very much

  Don

  Hi Don,

  Thanks for the additional information.  After doing research a bit more, it seems that there are 3 required properties so that the property of waveform to be set to yes.  These are wf_start_offset, wf_increment and wf_samples.  If you add in a call such as the following, this should solve the problem:

  DDC_CreateChannelProperty (lphchannel, "wf_samples", DDC_Int32, 5);

  Just replace with the length of your table 5.

  Kind regards

• How to store a path in a property of PDM

  I need to store a few Windows paths to other files as properties PDM, but (according to another post on the forum I can't now), the following characters are all illegal in PDM properties:. : , ; ' \ @ <> # [ ] % ( ) { } | * ? = ! "

  Many of those that are used in railways. I thought the conversion of each of them in its code of ASCII as a HTTP URL character, but the character '%' is in the list, too. Can anyone recommend an approach to managing this situation?

  I actually did something I almost never do. I was looking for tiaras online help. I found a page on thename for the properties of TDMS files conventions which States the following:

  "If you use one of the following characters in a custom property name, DIAdem replaces this character with an underscore:.,:, ',-, @, <, >, #, [,], %, (,), {{}}, |, *,?, =,!, ', ^, $, &, +, -, / and space." DIAdem also replaces a number first in the name of the property with an underscore. »

  It however does not anywhere that I found that you cannot use these symbols in a text in the dataproperty.

  Best regards

  David