'Length' of reading TDMS channel property

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• Read specific channels of an existing PDM file

  Dear users of Lab View,

  I would like to ask for help using the PDM read Vi to read specific channels in existing TDMS files.  I know to use the "contents of list TDMS" vi to that group names and channel list, but I don't know how then use this information to read identified specific channels.

  the problem, I'm trying to work around is to read a file of PDM with data from two channels, each with a different amount of data taken at different speeds. I would like to read a block of data from a single channel.  However, this data block contains more elements than the other channel. So, end of file error almost everytime I meet because the read PDM Vi tries to read this block of data for each channel.

  How can I specify the channel for the PDM read VI?  I tried to create a constant and fix them on the node "channel name" on the PDM read VI, but it gave an error.  I guess I don't know how to format.

  is attached the VI I'm trying to implement

  A sample file is too large to attach.

  Thanks for the tips

  I think that the problem may be that you close the TDMS of origin reference in each iteration of the loop, try to move outside as shown in the snippet.

  Note that I don't really went through the logic for the rest of your code.

  

• PXI-5122 and PXI-6259 read 2 channels simultaneously

  There is a single PXI-5122 digitizer card and a PXI-6259 DAQ card in our PXI system, we use Labview and TestStand (model Batch) to test the multiplication Board simultaneously, sometimes up to 8 boards are tested. We have some problems, such as the results of the tests is not reliable and sometimes blocking of Labview. Everything works fine when test single board. Thus, we feel that multiply causing this problem of acquisition of string data. It's great, if someone has the same problem and we can share the knowledge. My question is as follows:

  1. If two channels have been configured, read the two channel simultaneous cause blocking of the system or data damaged?

  "lu niScope WDT.vi" is reentrant, we can use two Subvi to call the "niScope Read WDT.vi' access the two channels simultaneously.

  2. If we set up a channel in another channel is reading the data, this situation will cause the search system or corrupt data.

  Concerning

  Samuel

  Hi Samuel,.

  You shouldn't have any difficulty to read several channels on your 5122 or between your 5122 and your 6259. You receive an error message when your test is blocked? What happens when your test is not reliable? Are you incorrect data and if so what is the data vs expected data acquired? You should be able to set both your channels in a single task, which would be using a read niScope WDT.vi to be used by the device. You are working from example or have you developed your own code? What version of the driver NOR Scope and NI-DAQmx driver do you use? You can find the driver version number in the measurement and Automation Explorer under the software section.

  What kind of test are you running? Your PXI chassis is controlled by a computer or by an on-board controller? Evolution of the rate of acquisition has an effect on your program?

• Read VeriStand channel from inside the custom device that are not part of the custom device?

  Is it possible to read VeriStand channels from within a custom device VeriStand (RT Driver) that are not part of this custom device?

  For example, suppose I want to be able to configure a channel in my custom device to always be twice the value of a string of material that my user selects (I know, better/more simple ways to do this, but this is just a simple example ).  Can I do this from the device custom without programmatically create a mapping of the system? (I've done this before and it is messy and VERY prone to error of the user).

  Thank you!

  good point

  the channel ID (U64s) are not the same in the engine config of vs. Instead, you must set 'references to dependent item' in the config and then get these references in the engine.

  See the source jarrod linked, which makes it

• I can read two-channel USB-6008 using THE Signal Express?

  Hello world!!

  Is possible to read the two analog inputs at the same time?

  Example: Using Signal Express, I need to read the (channel 0) analog input and analog input (channel 1) at the same time.

  I try this but, the signal on purpose gives me an error message saying that I can't read several channels at the same time using the USB-6008.

  Is this true?

  Thank you

  Ivo João

  André,

  Grato definition of pela.

  SUA ajuda muito util faith.

  SDS,

  Ivo João

• I have a DAQ Assistant configured to read several channels at the same time. When I have a graphical indicator of wire to the output, I see all my signals mixed together. How I divided them into separate signals?

  I have a DAQ Assistant configured to read 2 channels at the same time. When I have a graphical indicator of wire to the output, I see 2 signals mixed together. How I divided them into separate signals?

  When I wire any type of indicator, it is show that a release of a single channel.

  I want 2 indicators showing 2 different signals as expected from 2 channels configured. How to do this?

  I tried to use split signal but it end by showing that 1 out of 1 signal two indicators.

  Thanks in advance.

  Yes you are right. I tried, but I don't have the result.

  I just find the path. When we launch the split signal, we should expand it (split signal icon) by top, not the bottom. It took me a while to understand this.

  Thank you

• DAQ channel property node

  Hello world

  According to the statement, NOR for the verification of the Pxi4330 procedure, I need "Disable calibration shunt for the channel by using the property node DAQmx Channel, you can find custom I/O" DAQmx - data palette purchase LabVIEW. "'" ' Select the analog input"General properties" conditioning of signals ' bridge ' Shunt Cal "activate property of Shunt Cal. "but I can't select this property that I want to say there is no property such as?

  What is everyone knows what the problem is? I lost 3 hours to solve this stupid problem, still can not find it.

  When I choose the General Properties property, analog, node there are two options that are not the answer.

  Please help me on this

  Thank you

  Hi Eric,.

  You have an SMU-4330 installed on your system? There are MANY properties of different devices, and to avoid confusion of the properties that do not apply to you, DAQmx tries to hide the properties that are not applicable to all devices in your system.  If you don't have an installed SMU-4330 (or a simulation of SMU-4330), then the property you are looking for appear by default.  To find it, you have two options:

  Option 1: turn off the property node filtered by right-clicking on the channel property node, by choosing "Select filter...". "and then selecting"display all the attributes:

   

  or Option 2: install a real SMU-4330 or simulated in your system. You can install a device simulated through the program of Measurement & Automation Explorer (MAX):

  

• Reading TDM-"TDM C DLL" files to OR does not.

  Hello

  This isn't really a question of DASYLab, but I don't know where to post this:

  I want to read a file TDM using CT C - DLL provided on this page OR: http://digital.ni.com/public.nsf/allkb/A3663DE39D6A2C5A86257204005C11CA

  The sample data file created with DASYLab 12 (see attachments).

  (Attached) code is compiled without errors in Visual Studio 2010.

  When I run the executable, that an error is posted (see attached image).

  What is the problem?

  Yes, the reason for the error is the first group with no channel.

  I changed the example to read your file tdm without errors. Please take a look at the attachment.

• Sample quantity sample DAQmx channel property Node substitute in LabVIEW when = 1

  [cross posted from LAVA] 

  Problem:
  LabVIEW seems to be the substitution of a value of 1 to a value of 2 for the node property DAQmx Sample Quantity.Sample per channel for a continuous acquisition mode.

  Information:
  I have a task created in MAX (version 4.4.0f1).
  When I updated To Read samples 1 the task runs successfully in MAX.
  When I read the task in LabVIEW (8.5), the property node Sample Quantity.Sample per channel (i.e. the samples to read) is converted to a value of 2.
  If the value is greater or equal to 2 to the MAX, then the Sample Quantity.Sample by channel in LabVIEW property node returns the correct value.

  I get the same problem with a real or simulated device.

  Question:
  Is this desired behavior?

  Side note:
  If N samples (acquisition of buffer finish) is selected samples To Read cannot be 1 because it causes an error 200077 - must greater than or equal to 2.
  But no error will occur when the task is saved as a continuous (continuous buffer acquisition). I don't know if this is related. The error generated is:
  Error-200077 occurred to the DAQ Assistant
  Possible reasons:
  Measurements: Requested value is not supported for this property value.
  Property: SampQuant.SampPerChan
  You asked: 1
  Valid values begin with: 2
  Valid values ending with: 8589934590

  Shouldn't
  

  Hi JG,. Remember that the number of samples (one associated with DAQmx sync settings) is not relevant for continuous acquisition.  To read a sample at the same time, you simply specify this in your DAQmx playback function.  When you configure MAX to read an excerpt, it makes this same functionality automatically. You will not be able to get the value of another property node as the value is converted as soon as the channel is created (the value non-sous the constraint is not stored anywhere by the driver).  It should not be a need to this value in your code, if you want to read a sample to a schedule the DAQmx read simple example of function.  The amount of samples by reading is not part of the task itself, but is defined when running as an input to the function read DAQmx. You get the error message indicates that your device supports should not single-point HW timed - I would have probably asking which device you were using.

• DAQ write + read analog channels

  Hello

  I need urgent help to solve a simple problem:

  My job is to write an analogue channel to a data acquisition device, then read two analogue channels of the device.

  It must be made at the rate of 5 KHz.

  For the smaller rate I can do using normal loops (or timed loops). But I don't know how to make using the DAQ features.

  Please give me an example.

  I found something but I don't know if it can be used in this way (see attachment)

  Thank you!

  
  

• Get array (double) 2d reading tdms function

  Hello

  I want to get o a 2d from a PDM file table. I use tdms read for this, but it gives table 1 d out of it. Kindy help me. Please find the attachment.

  Please pass an 2d to Terminal 'data type' reading PDM.

• TDMS NI_DiskCacheSize property

  Hi all

  I came with the property set TDMS named NI_DiskCacheSize.

  Can someone tell me please how to put 2 MB cache using this property?

  What exact property value I should write to set cache size 2 MB for TDMS files?

  Help will be really appreciated.

  Thank you

  Thank you very much

  Its really useful.

• Read the channel 1 and channel 2

  Hello

  I went through the basic course Lab View 1 and I'm starting to understand some of them. I struggle to write the next request in Lab View 8.5 and version 2011.

  I need to write a VI for the Tektronix TDS 210 2 channel oscilloscope to be able read channel 1 and channel 2 (x and y). Also, I have to run this scope as scope of digital storage (remember the waveform in the memory and be able to remember specific time range) I downloaded the driver for the scope and I am able to run the only form of wave or multiple wave VI, but I do not know how to change these VI in order to function as I mentioned above.

  I need to know how I can lock this VI as the instrument always follows the same GPIB address.

  Could someone help me with this project please?

  Thank you

  Joe

  Make a constant on the block diagram. It is an option to click right when you are on the block diagram. I also recommend the creation of an alias for it to the MAX (i.e. "extended"). In this way, if the address changes, you don't have to change the program.

• Impossible to read 4 channels with the or 9234

  Hey, I'm tasting 4 simultaneous channels to 51.2 kech / s rate for each channel with the NI 9234 module.
  I use a callback function to read from the buffer.
  I am accept to get to playback 4 channels of 51.2 k * 4 = 204.8 k s/s.
  and I still recive data 51.2 kech / s.

  Need help, I don't know what's wrong with my code.

  I enclose my hope of code it will help...

  Thank you!

  My installation information:
  Material: NEITHER 9234
  Version of Windows: XP
  Language: Qt (C++)

  Hey simon27,

  When you have installed DAQmx, did you also install text code support? There are several examples that should have installed with DAQmx which is very helpful in getting you started. "" "" "They can be found by going to your Start menu, then all programs" National Instruments "NOR-DAQ" NOR-DAQ "support textual Code ' ANSI C examples.

  In case you do not installed the supported text based code, I have attached two examples which I think would be more useful to you. Try to run these examples and see if you get the same errors.

  -Nathan H

• How to read several channels simultaneously with a minimum

  Hi all

  Please see the attached file. In fact, this is a simplified example of my real application, I didn't understand the second half to reduce the complexity.

  As demonstrated, I have two entries of analago I need to read (position and acceleration) with a SPECIFIC requirement which is:

  At the same time, I make some decisions based on data more recently acquired in the "timed loop. The decision part is not included in this vi. for simplicity. But the fact is that I just need the most recent data (as well as online) make a kind of decisions.

  Everything seems fine and it seems that I collect data in a way desired interval of 1msec. BUT I just discovered that the data I read (in the timed loop) are the most recent one compare is not to the real sensors. In other words, there is a delay in the acquisition process. The value in the timed loop is like 100 msec delayed the release of real sensor, which is generated by the sensor and acquired by DAQ card.

  This problem makes my decision making part of constantly decide according to the before value of 100 msec. Unfortunately, it's terrible to my request, i.e. it is an intolerable delay to the process.

  Are my settings of data acquisition as samples per channel, the number of samples per channel or right of sampling rate? I appreciate if someone can help me with this application. I just need to collect data at 1 kHz, as close as possible in real-time (online) or with a minimum delay, not 100 msec.

  Thank you.