sampling frequency of acquisition and FIFO on 9205

Similar Questions

• Sampling frequency and Nyquist theorem - data acquisition

  Hi all

  I have a rectangular steel beam that is affected with a weight of 100 kg and I would look for the modules able to sample the signal correctly.

  The Nyquist theorem says that if half of the sampling frequency is higher than the input signal, it will be recorded correctly.

  What I think about it before you buy a data acquisition module to find the signal of the rectangular steel beam? I will perform an analysis model by finite elements using the elastic properties or properties of plastic? Is the natural frequency of the associated structure of the input signal?

  Thank you

  Husband

  Some technical assistance is appropriate, determine that the higher frequency component is interesting to your signal. Set your frequency of sampling to twice this value. In addition, to protect data, to build a filter of antisliasing of material it alleviates any energy above the highest frequency of interest.

  Mike...

• Doubts about the sampling frequency when the production and acquisition

  When the generation and acquisition of samples, the maximum sampling frequency is the maximum sampling frequency Council divided between the generation and acquisition of task number?

  Thank you

  Hi Houari,

  You should read the specifications of your box DAQpad!

  It is clearly said: entered analog = 200kS/s rate sampling, but analog output = sample rate of 300 s/s or even just 50 s/s for the hardware timing!

• How to acquire with NiScope at different sampling frequencies and lengths Records?

  I need to acquire the data of 2 channels of the NI PXI-5114 map two different sampling frequencies high, at the same time. Also, I put 2 different record length. Is this possible?

  I understand that 'Vertical' settings can be configured for individual chains because the function 'Vertical niScope Configure' has 'channels of entry with which we can assign the desired channel. But for horizontal settings such as "min sampling rate" and the record min length, I could not find such an option to specify the channel. Would it not common to both channels?

  I hope that the device is capable of simultaneous sampling and therefore channels can be configured individually to different sampling rate.

  Hi AJ_CS,

  Why do you have to be distinct from sampling frequencies on channels separated from the digitizer even?  What different sampling rate do you want?

  But for horizontal settings such as "min sampling rate" and the record min length, I could not find such an option to specify the channel. Would it not common to both channels?

  You do not have an option to configure the settings of hoirizontal on a channel by channel basis because this concept does not exist in the traditional sense of the use of a scope.  Compatible with the concept of IVI, an oscilloscope traditional benchtop will have only a button or a set of buttons for setting the parameters of synchronization of the unit.  There is therefore no horizontal configuration to separate channels on the scanners NOR.

  I hope that the device is capable of simultaneous sampling and therefore channels can be configured individually to different sampling rate.

  Similar to a traditional benchtop oscilloscpe, the device is capable of simultaneous sampling.  But as mentioned above, the channels can not be configured for different sampling frequencies high.

  However, you can ignore data that you think is not relevant.  For example, if you assign 100MS/s CH0 and CH1 to 50 MS/s, then you throw all other samples.

  Alternatively, you can use separate scanners (a channel on each digitizer) and configure them to taste at different rates.  You can set frequencies of sampling on scanners NOR separated and even synchronize them with TClk.

  -Andrew

• Sample of high acquisition rate of data using data acquisition and continuous data backup. Also I would chunck data into a new file in each 32 M

  Hello:

  I'm very new to LabView, so I need help to find an idea that can help me to record data continuously in real time. I don't want the file is too big, so I would like a new file in Crete in each 32 mega bytes and clear the previous buffer. Now I have this code can save data of voltage in the TDMS files and the sampling frequency is 2 m Hz, so the amount of data very fast increase and my computer have more ram 2 G, then the computer hangs after 10 seconds, I'm starting to collect data. I need some advice you briliant people.

  Thank you very much I appreciate really.

  I'm a big supporter of the architecture of producer/consumer .  But this is the place that I recommend.  The DAQmx Configure Logging does all that for you!

  Note: You will want to use a table instead of a graph here.

  

• Synchronization of the inputs and outputs with different sampling frequencies

  I'm relatively new to LabView. I have a NOR-myDAQ, and I am trying to accomplish the following:

  Square wave output 10 kHz, duty cycle 50%.

  Input sampling frequency of 200 kHz, synchronized with the output that I get 20 analog input samples by square wave, and I know what samples align with the high and low output of my square wave.

  So far, I used a counter to create the square wave of 10 kHz, display on a digital output line. I tried to pull the document according to (http://www.ni.com/white-paper/4322/en), but I'm not sure how sample at a different rate than my clock pulse. It seems that this example is intended rather to taste one entry by analog clock pulse. There may be a way to create a faster clock (200 kHz) in the software and use that to synchronize the analog input collection as well as a slower 10 kHz output generation square wave?

  I eventually have to use the analog inputs to obtain data and an analog output to write the data channel, so I need the impetus of the square wave at the exit on a digital PIN.

  How could anyone do this in LabView?

  Hi Eric,.

  All subsystems (, AO, CTR) derive from the STC3 clocks so they don't drift, but in order to align your sample clock HAVE with pulse train that you generate on the counter, you'll want to trigger a task out of the other. I would like to start by a few examples taken from the example Finder > Input and Output material > DAQmx. You can trigger GOT off the train of impulses, start by Gen digital Pulse Train-keep -you probably already use a VI like this to generate 10 k pulse train. AI, start with an example like Acq Cont & chart voltage-Ext Clk - Dig Start.vi-you'll want to use the internal clock so just remove the control of the "Source of the clock" and it uses the internal clock. From there, simply set the "Source of the command" either be the PFI line generates the meter, or ' //Ctr0InternalOutput '-assuming that you are using the counter 0. You'll want to make sure that the start of the task HAVE faced the task of counter I is ready to trigger off the first impulse. They should be aligned at this point.

  For debugging, you can use DAQmx export Signal to export the sample clock - you can then brought the train line and the PFI pulse to make sure that they are aligned.

  Hope this helps,

  Andrew S

• Sampling frequency for two different routes for acquisition of data USB-6009

  Hello

  I use a box USB-6009 and incorporating the "daq assistant" to change the sampling frequency.  I'm trying to find a way to set the sampling frequency to two unique values for the two separate channels.  I tried implementing two assistants daq and different for each channel sampling frequency setting, although it does not work.  Is it possible to set the sampling frequency for all channels, and then reduce the rate for another channel - or an alternative?  I would be recognizing any input on this matter, thank you!

  -Anthony

  All tasks on a DAQ card using the sample clock should use the same clock.  Therefore, you cannot have two tasks on the same sample of DAQ card at different rates.

  Alternatives would be:

  1. to combine all channels in a single task and to accept additional data

  2 get an additional DAQ card to use at the same time

• What is the relationship with the sampling frequency and number of samples per channel?

  In my world, if I wanted to taste 10 seconds 10 Hz (100 s/ch), specify a rate of 10 and a number of samples of 100.  This would take 10 seconds to return data.  The task does not appear to behave this way.  No matter what rate and the number of samples, I chose, I spammed with data at 1 Hz or more.

  What I am doing wrong?

  This problem is resolved by making a request for telephone assistance.  It turns out that the minimum sampling frequency of the NI 9239 is 14xx s/s.  I don't know why there is a minimum sampling frequency, but now I have to go to the next question discussed at this link:

  http://forums.NI.com/T5/Multifunction-DAQ/how-can-I-read-gt-10x-samples-at-a-sample-rate-of-X/TD-p/2...

• HAVE sampling frequency is divided by the number of channels + 1 for simulated ENET-9213, WLS-9213 and USB-9213

  Hello

  In the code in the example attached, I create a task with a single channel of AI.

  I get the maximum sampling frequency using DAQmxGetDevAIMaxSingleChanRate (or DAQmxGetDevAIMaxMultiChanRate), both return the same value of 1351 s/s.

  When I try to configure the sample calendar using DAQmxCfgSampClkTiming at the maximum sampling frequency clock he does not accept the rate and returns the following error. Note that the error message shows 2 channels, even if only a channel has been added.

  OUTPUT:
  DAQmx error:
  Sampling frequency is greater than the maximum sampling frequency for the number of specified channels.
  Reduce the sampling frequency or the number of channels. The increase in the conversion rate or
  reduce the time of the sample can also mitigate the problem, if you define one of them.
  Number of channels: 2
  Sampling rate: 1.351351e3
  Maximum sampling frequency: 675.675676

  Why the device driver thinks I have 2 channels in the task, when a channel has been added?

  Please find the code to reproduce this problem attached.

  Kind regards

  whemdan

  The MathWorks

  Hello w,

  By default, the ENET/WLS/USB-9213 in NOR-DAQmx module has the AI. AutoZeroMode the value of the DAQmx_Val_EverySample property. This causes NOR-DAQmx acquire the channel of the internal path of the unit (_aignd_vs_aignd) on each sample to return more specific measures, even if the operating temperature of the device moves over time. If you need the sampling frequencies higher than this allows, you can call DAQmxSetAIAutoZeroMode(..., DAQmx_Val_Once) (who acquires the formatting string when you start the task) or DAQmxSetAIAutoZeroMode(..., DAQmx_Val_None) (which disables the setting entirely).

  Note that for measures by thermocouple with cold junction compensation sensor of the 9213 NOR, NOR-DAQmx acquires channel built-in CJC (_cjtemp) on each sample as well, for the same reason.

  Brad

• Reading and samples the sampling frequency using a fast external clock

  Hello

  I use an NI USB-6212 box to launch a search engine for combustion. I have a pressure sensor in the head and a wheel on the crankshaft. I use the beats A Quad channel of the rotary encoder as a sample external to the pressure with the sample clock. The idea is that I want almost the same number of points in each trace of pressure so that it is easy to average together. I seem to be able to do this at low speed, but I'm having issues at high speed.

  Can someone tell me what I should have my sampling rate and samples to read together and how it effects my sampling when using an external clock? Samples per channel will affect the size of buffer and that matters? When I was high (10-100 kHz and about 1/10 * rate for samples to read) it barely read but as I put the lowest and lowest he read faster. Play with the settings a bit seem to affect how well it samples at different speeds. The engine is running at 3600 rpm and my encoder puts out 2500 pulses per turn on one channel, I'm looking at a frequency of 150 kHz effective sampling. However I didn't sample program with the engine operating at full throttle. I hung on the output of the encoder up to a scope and reads very well.

  Are there opportunities the filter counter that I see in the manual of 621 x is enabled inadvertently?

  Thank you

  Xander

  Xander18,

  I suggest you move your screws initialization outside the while loop, as well as your narrow DAQmx VI.  On my side, it looks like a new task is performed for each loop, which takes time.  That a try and let me know how it goes.

• Sampling frequency of HAVE is incorrect for simulated ENET-9213, WLS-9213, and USB-9213

  Hello

  ENET-9213, WLS-9213 simulation and devices USB-9213, I'm able to correctly get the sampling frequency of I = 1351 samples/s using DAQmxGetDevAIMaxSingleChanRate, which is incidentally on the value of spec'ed of 1200 s/s.

  However, when I create a task and add a voltage channel and then HAVE the sampling frequency of the task of query, I get a sampling rate of only 9 samples/s. I tried the same code with other devices and I get the sampling frequency corresponding to the device data sheet, it seems THST this problem is limited to 9213 devices.

  Why sampling returned by the task using DAQmxGetSampClkMaxRate rate returns than 9 s/s.

  And why the rate of conversion of DAQmxGetAIConvRate only 18 s/s.

  I enclose the test code which may be used to reproduce this problem.

  Kind regards

  whemdan

  The MathWorks

  Hello

  When I tried this with a USB-9213 simulation, I used the Sample clock Max Rate, as well as the Rate.vi of AIConvert:Max property node.  I could see that for 1 channel, I could spend up to 675.67/s, and I couldn't for 16-channel get79.49S/s (which total is equal to 1271 S/s, which is in the specifications).  The multichannel and single channel, I could get an AIConvert Max Rate of 1351.35.

  Something that could happen is that you do not explicitly set this device runs in mode high speed.  You'll want to set the property Get/Set/rest AI_ADCTimingMode channel at high speed, and you should see much better results in this way.

  Something else to note - I use DAQmx 9.0

• WLS-9163 and 9211, sampling frequency of evil?

  Hello!

  I have a WLS-9163 with 9211 mounted module. I have connected a single thermocouple type K to the analog input 0.
  I can connect and perform measures wireless. However, I can make only 7 s/s without error message.
  I get the following error message when I try to taste 14 s/s in the configuration of WLS-9163.

  Error-200081 occurred to the DAQ Assistant
  Possible reasons:
  Sampling frequency is greater than the maximum sampling frequency for the number of specified channels.
  Reduce the sampling frequency or the number of channels. The increase in the conversion rate or reduce the period of the sample can also mitigate the problem, if you define one of them.
  Number of channels: 2
  Sampling rate: 14.000004
  Maximum sampling frequency: 7.142857
  Channel name: _WLS-14049AF-2/_cjtemp

  When I use the 9211 in a cDAQ-9172 configuration I can acquire up to 14 s/s of a single channel with no problems at all.

  Somehow he thinks that I chose to take measures to channels, that is not the case.

  I use Labview 8.5.1 with hardware drivers of 2009-10 with Windows XP SP3.

  Is this something you've heard before?

  Best regards
  Mattias

  Mattias salvation,

  Your task is also reading the CYC on the unit once for example, if you are done reading of two channels.  Reading of the CCM (it's the .../_cjtemp in the error message) is required to return a value of temperature measured from a thermocouple.

  Kind regards

  Kyle

• square pulse time rather than the sampling frequency and size dependent frequency

  Anyone know if it is possible to create a pulse square with its dependent on the frequency at the time rather than the sampling frequency and size?

  for example if I set the frequency to 10. That means 10 pulses per second.

  rather than having to set the sampling rate and use the equation

  frequency = [(# of cycles) * (sampling frequency)] / sample size

  Thanks in advance. a photo of the block diagram would be grateful if possible

  NVM, that I solved it

• 6608 period or frequency limit of sampling frequency

  I use a card counters/timers 6608 and want to measure the period of a square wave of variable frequency.

  I need the period of each rising edge because this same front is used for my external clock analog data acquisition cards.

  In this way, I know the time between measures of individual position.

  I used the example VI soul ctr.vi hollow low frequency Freq 1 and add the code appropriate to read continuously.

  I use a function generator to test the equipment and it seems to work fine until 100 kHz.  After that the 200141: data has been replaced before it could be read - error takes place.

  This error takes place at exactly the same number of pulses every time I try running at a given frequency.

  I could not find information that would be me index a limit to the frequency of measurement period on this map.

  If anyone else has had a similar experience and it is a limitation or is there a setting I'm missing?

  Thank you

  DVS,

  Please post on the Forums of NOR. This overflow error memory buffer that you see is because our advice of counters/timers have a buffer FIFO of two samples for counter measures. What you run, however, is the fact that you take action as soon as your computer can DMA transfer these measures out of the buffer. I would suggest trying to use other measures to counter as "two meter - range" to see if that would help you take frequency readings higher.

  Our documentation on the FIFO can be found here. I hope that clarifies the question a bit, thanks!

• How to acquire the signal to very high sampling frequency

  Hello world

  My name is Luke Ho. I am trying to acquire the signal with Labview (Sthelescope). The signal comes from sensor acoustics, then filters and amplifiers to adapt to ADC rank (0 - 5V). Thus, the maximum frequency of the signal is 40 kHz.

  According to the Nyquist theorem, I sampled at least 80 Khz signal.

  Is there a sampling frequency devices like that? or y at - it another way of better? I used the Arduino before, but it was about 10 kHz.

  I need your advice.
  Thank you all and have a nice day.

  holucbme wrote:

  Thanks for your recommendation

  But is it possible without USB Data Acquisition, it is quite expensive for me.

  This is the cheapest option to NEITHER. I tried to look for options to other companies, but more I found in the same price range, or not answering is not your condition of sample rate.