On the NI PCI-6221 fast sampling rate question

Similar Questions

• fast sampling rate question...

  Hello

  I use USB-6009 and max sampling rate is about 48 K samples/s according to

  the specification...

  Question 1.

  48 K samples/s means... only when you receive 1 analog input?

  If I have 2 analog inputs then forge would be just half of the 48K?

  Question 2.

  using the daq assistant.

  I would like to get about 50 samples between 10ms

  If I do the math I get 5 K samples/s, which is enough for me

  However, I played with samples to read and throughout the day, the sampling rate,

  do not get this rate... (I'm outputing in file with LVM)

  I searched on the sampling frequency, and people here said

  samples read and sample rate do not havea correlation...

  but I see clearly that they are relevant. When I change a setting

  I get a different number of acquisition... I do N smaples.

  Please help:)

  Q1. Yes, except that the switching of channels takes awhile so the net price per channel is slightly less than half the rate of single channel.  The USB-6009 specification document does not indicate what is the switching time.  You should be able to get 5 kHz on both channels.  20 kHz might be close to the upper limit, but that's just a guess.

  Q2. The DAQ Assistant is often not the best choice for maximum performance.  I do not have the DAQ Assistant, so I can't be more specific. If you get the data as an array of DBL, rather than dynamic data type, it can be recorded directly, without conversion.  The other thing that can make a big difference is a loop two architecture of producer/consumer.  This allows the acquisition of data and save it to the file to run it at different speeds so that each can be optimized separately.  If you are trying to acquire 50 ms of data at a time and then, he writes to the file, you write to the file twenty times per second.  The first time, the operating system must reallocate some file space or do something else what delays write the file, your timing loop is disrupted.

  Lynn

• I need to generate 3.3 V logic level Digital train of pulses with the NI PCI-6221. Can I change the level of 6221 OR logic output?

  I need to generate 3.3 V logic level Digital train of pulses with the NI PCI-6221. Can I change the level of 6221 OR logic output?

  The output cannot be changed. 5V to 3, 3V level controllers are readily available (Maxim, I think). As long as the scanning speed (etc.) is fast enough for your pulse train, even 3, 3V regulator would work. I don't know if NEITHER offers a module to condition TTL levels.

• With the NI 9205 module Max sampling rate - problems

  Dear friends,

  I develop a project of lv, which makes and control system of engine dyno. The material is CRio-9022 with other cards and also 9205 for AI. There is an encoder for angle attached to the motor shaft with 3600 chatted by Tower as well as an index to indicate the end of a revolution. the output of the encoder is measured by card 9411. The speed of the motor is 1500 rpm. I measure pressure data and couple when I receive a 'tick' of the wheel. This means my sampling rate for pressure and torque each is 90KO/s.

  but I was not successful to lead it. The program is great and I can show them, but I believe that there is a problem in the choice of material for the task. With the data of pressure and torque of the 9205, I also measure other channels for the controller output mass flow and temperatures. So in all I use 8 channels of the 32 available. But only the pressure and torque are acquired at the wheel-driven sampling rate. the rest are acquired about 5 times per second.

  Since the 9025 is a multiplexing ADC, 250K sampling frequency is divided by the number of channels accessed = 250 K/8 = 31 K samples/channel. With this in mind, I decided to acquire data of pressure and torque with each beat 3rd rotary encoder, essentially on 30K samples/s sampling. However, I see a large amount of noise.

  So I decide to average more than 1 second cycles (so the engine runs at about 25 cycles/sec, I averaged over this issue). The resulting pressure and torque graphics do not match with those measured by an oscilloscope in terms of amplitude but the frequency and shape is correct.

  I noticed an interesting feature in the charts. When I pass interpolation between the points, I see several curves made by points instead of a continuous locus of points. Accordingly, I find that the acquisition is slower than necessary, and so there are less number of points sampled as required. These points are not synchronized 25 cycles I have on average and therefore the separate "curves". It is because of the possibility that some points receive a higher number of 'contributions' several times (when you add), the neighbouring points.

  so I conculde that the 9205 is not fast enough to do the job. also noise, perhaps due to crosstalk or gosting when the mux changes channels. the impdences output pressure and the couple are of the order of 10 K ohms.

  the Labview code outline: well, there is a vi FPGA, which takes the rotary encoder ticks and sends a signal to the case of each 3rd tick. The signal contains a 16-bit integer, indicating the number of ticks. This signal is sent to a 1 element FIFO. This fifo is read in a parallel while loop, where it remains awaiting a new element. The while loop bed fifo, where data are available, takes a measure of pressure channel. A node memory of the method is called to provide data according to contained in the index number equal to the number of ticks to signal fifo. Then he adds the current pressure reading to the reading of the memory and stores the sum in the same memory location.  Thus, an array of elements of 1200 is formed, where each elemnt is a sum of the values taken of more than 25 cycles. This memory is transferd to a dma fifo and reading side host. is done similarly to involved couple. host-side the fifo is read and divided by 25 to get the average. This average is displayed on a waveform graph.

  Please check the attached file to get an idea of the problem. Sorry for the long post.

  Please suggest if you understand the problem and suggesstions or solutions.

  
  

• Impossible to test, check, calibrate the card (PCI-6221) DAQ with MAX

  Hello

  We bought a PCI-6221 DAQ card and we have installed. However, it seems that the device is not recognized. First of all, it appears as a device in the PXI system then that is a PXI system. Then, I don't have access to the 'properties', 'self test' and "to calibrate" menu. This issue should be linked to the first.

  I tried to remove the driver and install it again, but it didn't work, so I tried the update but it is the latest version. Is there a problem with the driver?

  I checked with Labview if it was possible to use it, but no devices were found by the DAQ assistant. We have the whole NI Developer Suite 2009.

  Thank you for your time

  Cedric THOMAS

  Hello

  It works! Great! Thank you very much for your help.

  However, does this mean that DAQmx 8.8 is having trouble with the PCI-6221 device? Or I made a mistake during installation (but I have followed the manual)...

  I even can I create a simulated device also. That I couldn't do before with MAX 4.5.

  Thank you

  Cedric

• Continuous monitoring of the mouse (USB) with fixed sampling rate (500 Hz)

  Hello

  I'm quiet new to LabView and there are simple applications that I am still unconfortable with. I have to constantly monitors some analog channels to my DAQ and simultaneously to the value of X and Y of the mouse (USB). Signal acquisition of surveillance data are a simple procedure, but how to capture X and Y of the mouse as contibuous undulations sampled 500Hs (for example) so I can merge them to signal data acquisition? What is the synchronyzation of the signals of the acquisition of data and the extra-DAQ chanels created with data from the mouse?

  Thanks a lot for your help and your patience!

  Olivier

  Quick explanation:

  When I said "throw a timed loop around this" what I really wanted to throw a loop timed around "acquire input data.  I don't know how it applies to these screws (it certainly when you talk about material!), but generally when talking to a device we open/close only once and loop on the functions of acquisition/generate.

  

  -memoryleak

• compactDAQ sample rate question...

  OK, I think I have a question in the right place, but if not I have forgiveness.  :-)

  I have a CompactDAQ (4slot) with just a 9225 and 9239 modules installed.  I've run the DAQ assistant and have all seven current channels of reading and writing in a text file of a structure of event... when I push the button, it saves the data.  Quite simple really, I have also a timer Setup 'Wait' with a 50mS wait time, so I'm basically updateing my loop 20 times per second, not so fast.  The strange thing is that my DAQ module is only send me data once per second.  A I put something wrong?  Seems to me that as updates of loop, it should return 'true' the key to the structure of the event and the data should appear at a rate of about 20 samples per second.   VI attached sample.

  Tips and points in the right direction are greatly appreciated!

  Chad

  Hi chuggins143,

  The behavior comes from your settings in the DAQ Assistant:

  

  If you want the loop to run 20 x per second, then 'Samples to Read' should be 1/20 of the sampling frequency.  DAQmx hangs until the samples 'Samples to Read' became available, so it's slowing down your loop.  You can also change the Timing settings to 'Continue', if you want to avoid gaps in your data.

  Best regards

• Block in the amplifier with high material sampling rates no DSA

  Hello

  I intend to use the starter kit OR locking amplifier to detect a harmonic signal of 400 all about. I intend to use the PCI-5105 digitizer (I don't him have not bought until now, but I will soon). The start kit lock, I downloaded and unpacked the files and was hoping to give it a try with an NI USB-6363 however the vi does not open because it says that there are a lot of sub - VI lack (Subvi read.vi I HAVE... clear.vi, etc.). The LockinDemo.vi also seems to use NI 4472 as a default material. My questions are if the lock-in-amplifier starter kit OR 1) can be used with PCI-5105 and 2) cannot vi missing of the be downloaded from somewhere or be replaced by other blocks on mine?

  Thanks in advance for any help

  Benoit

  Hi Benoit,.

  First to start development with LabVIEW Real-time, you can check if your system supports LVRT. You can make use of RT disk utility that will test your system as shown in this article: http://digital.ni.com/public.nsf/allkb/9209361E17708D548625744A007FF353

  We have lists of equipment belonging to systems tested here: https://decibel.ni.com/content/docs/DOC-10692 and you can always check for the other hardware compatibility here: http://zone.ni.com/devzone/cda/tut/p/id/8239

  We do not have a driver available for the PCI of pledge cards but if these cards use VISA calls, you can develop and LVRT recognizes your card by following the KBs:

  (1) acknowledge the third peripheral part with LVRT: http://zone.ni.com/devzone/cda/tut/p/id/3142

  (2) expand LVRT peripheral Driver PCI: http://zone.ni.com/devzone/cda/tut/p/id/3251

  I hope this info helps!

• on the sample rate of PCI-6723

  According to the specification of PCI-6723, faster sampling rate is 45kSample/s, 32 channels working simultaneously. But he's always fine when I put the sampling frequency to 200kSample/s, 32 channels working simultaneously. This configuration will damage the material?

  Ok. I assume you mean update rate of sampling frequency not.  As long as you use the onboard buffer you can reach 204Ks/s 32 channels.  Since you do not get an error the device and things work it is probably what you're doing.

  You had asked the rate could only be achieved you would have been a mistake.  And the material would not be damaged by incorrect update rate adjustment.  You're ready to go!

• PCI 5154 sampling rate

  Hello

  What is the sample rate max 5154 PCI for two channel inputs? The manual States the 2GS/s is for one channel only. So, am I not able to get a bandwidth of 1 GHz for the simultaneous measurement of two channels? Thank you!

  Hi gbhaha,

  First of all, TIS mode up to 20 GECH. / s using an ADC, while your real time sampling uses two converters a/n at the same time to a single channel.  Take a look at these diagrams that I linked in my first post for more details on this architects.

  About the difference in the bandwidth between the 5153 and 5154 - the 5153 has 500 MHz of bandwidth in its circuits, even when acquiring at faster sampling rates.  The 5154 1 GHz of bandwidth, this is why it is more expensive.

  Kind regards

• Sampling rate higher for the measurement of precision meter

  I have a BNC 6259 M Series DAQ USB. I am currently using the DAQ Assistant to perform simple cash rising measured with the measuring mode single sample on request. I tested my VI with a known square wave with a function generator signal and it clearly lacks a few edges. I think that the solution lies in faster sampling. However, I was not able to understand how to use clocks to set up continuous sampling mode. I tried the forums and I found articles that were close, but not quite exactly the problem I am facing with as (http://forums.ni.com/t5/Digital-I-O/trying-to-use-NI-6251-s-DIO-port-as-input-and-output/m-p/448035#...) or (http://forums.ni.com/t5/Multifunction-DAQ/Using-Counter-of-PCI-6024E-with-Quadrature-Encoder/m-p/984...). Any guidance here would be great.

  In fact, the calendar should not have anything to do with the edges being detected.  Configuration of a sample clock for a county of just edge task allows you to enjoy deterministically in the account register and has no impact on the edges which can be counted.  Also, the analog examples really have nothing to do with what you seem to be asking questions on.

  ... So it leaves the question unanswered as to why you might miss the edges.  Perhaps the following information could shed some light on the question:

  1. it is possible that you do not configure the counter exactly as you think you are.  Can you post the VI you use?  As a point of reference, count digital events shipping example does not use any clock sample timing and just questioned the value of the register count with a software loop, but the meter should not miss all this edge on the input source.  There are examples that are timed by the material available as well, but this is not necessary, unless you need a constant specified dt between your counter samples.  To use the examples of the timed sample, you will need to generate a clock of either another subsystem on the map or use an external clock.

  2. assuming that the configuration of the counter is not the issue, there may be a problem with the method that you use to determine if you are away from the edges.  How do you know that you are away from the edges?  The function generator produces only a finite pulse amount?  You start the meter before start out impulses?

  3. If the two points above do not raise red flags, it seems likely that the meter is registered just not some of the impulses of your FGEN.  Can I assume that the output of the FGEN is 0 - 5V TTL?  What is its frequency and duty cycle?  The maximum external source for the meter on the M-series products: DAQ (like the 6259) is specced at 20 MHz, but this depends on a clean signal with good connections.  At frequencies above it, the bandwidth of the front-end of the PFI lines becomes limiting.  If you have an available specification document for your FGEN I'd like to be able to see it.

  I hope this gets you throw on the right track to solve the problem - impatience comes back with more information.

  Best regards

• Explore: Discover: Choose Details: Audio sample rate and the size of the Audio sample are not available in the list choose the details.

  With audio files (in particular the WAV), Audio sampling frequency and the size of the Audio sample are not the choices available in the list of details with Vista.  In earlier versions of Windows (2000 and XP) they were both selectable as details.  Is it possible to get these will appear under Vista?

  Vista - related audio details available:
  Album
  Album artist
  Bit depth
  Bitrate
  Duration
  Kind
  Year

  2000 / XP - audio related details are available:
  The album title
  Artist
  Audio sampling rate
  Audio sample size
  Bitrate
  Kind
  Title
  The track number
  Year

  FWIW, sampling frequencies are discussed in the Help window and how to (below).

  Reference: http://windowshelp.microsoft.com/Windows/en-US/Help/53adb4c7-d538-42f8-bb13-917379922afe1033.mspx

  Thank you!

  For the third part of the applications that perform many tasks, I usually discover www.tucows.com and www.download.com.  They have a wide variety of programs, and the trick is to put in the correct search terms to find what you are looking for.  Make sure you that your selection is compatible with Windows Vista and at tucows, try to pick one with 4 or 5 cows because they are the highest rated.

  Good luck! Lorien - a - MCSE/MCSA/network + / A +.

• The sample rate conversion

  Hello

  If I scan documents to Audition 2.0 48 kHz and then convert to 44.1 using software for recording on CD, would there be loss of quality?

  Thank you.

  If it has voice recordings and you need an original CDs can just master at 44.1 k and have done with it. Since there is no content in your files anywhere near the limit of Nyquist (this is half of the sampling frequency and represents the highest frequency at this rate, you can save), then all you need to do is an extra oversampling when the format of distribution requires.

  The speech contained in frequencies up to 12 kHz (hopefully) and even if you add music the answer will not exceed 20 kHz - and in any case, this is where the human ear cup (in children - rather less than that of adults). Therefore recording at 44.1 k means that you will capture all this, and you will be able to register without creating large files by scanning of a plu top noise load audio - which is all that recording at a higher sample rate will reach.

  If you need pace to a different distribution format, then you have lost nothing - just do it when you need to.

  I record a lot of original acoustic music and unless specifically requested to (which is never arrived, I might add...) I always master to 44.1 k. It's been proven by research academics caution that no one can tell the difference, then what is the point of a high sampling rate, besides wasting disk space unnecessarily?

• than 25 ns sets sampling rate...

  Hello

  I'm trying to test the sampling rate of chassis cRIO 9103...

  I created a simple FPGA project, for sampling sign this clock frequency of the FPGA equal to 40 Mhz (on by default). I applied 1 Mhz square wave to pin MISO DIO6/SPI, place one of the slots on the frame... I put a tick 'loop timer' in ' ' loop for every moment of picking (totally 32 sampling point).

  input signals a cycle = 1000 ns (1 MHz) and I m planning see samples every 25 ns (40 MHz) on the graphical waveform. But the chart shows me only 10 points for 1 cycle like taking samples of every 100 ns instead of 25ns. (FrontSamplingRateObservation.png)

  What is to be? If so, how can I get faster sampling rate...

  I joined .vi photos of the project...

  You can consider that the only timed cycle lines and the pipeline of the operation.

• SC-2345 misconfigured and PCI-6221

  Hi all

  I have the following configuration:

  Windows XP

  OR PCI-6221 (68 pins)

  SC-2345 (several modules installed: 4 x SCC-TC02 in J1 - J4, 1 x SCC-CI20 to J5, SCC-SG24 to J6 1 x and 2 x AI04-CSC J7 & J8)

  LabVIEW 8.0

  NOR-DAQmx 8.1, MAX 4.0.3.3

  My card PCI-6661 passes its self-test and seems to be fine in MAX. My SC-2345 carrier seems to work (the power Board - CSC-PWR02-LEDs light up). I configured the SC-2345 and CSC modules by the manual, click on 'OK' to save the configuration to MAX. but when I try to run the test panels on clusters to copy single (all except the NCC to power), I get this error (same for each CSC, although 'the physical channel name' changes for each):

  200170 error occurred at the test Panel

  Possible reasons:

  The physical channel specified does not exist on this machine.

  Refer to the documentation for the channels available on this device.

  Device: Dev1
  Name of the physical channel: ai0

  I'm baffled at this stage, so any help/pointers would be great, thanks.

  Hi Luis,.

  Thanks for the reply. I do not end up installing a newer version of DAQmx, although not later (when I tried the latest version, I ran into issues with screws in my old version of LabVIEW). I ended up going on the way to upgrade DAQ after reading the manual PCI-6221, who has taken on DAX 8.7.1 or later, so I installed 8,71, and who finally solved the problem.

  Interestingly, as far as I can tell MAX, the system is exactly the same; somehow under the MAX, the software of data acquisition software is to connect the dots for me.

  Thanks again,

  Dan