NEITHER 9234: sampling rate: cRIO, FPGA

Similar Questions

• Different sampling rate with the same connector AIO, Labview FPGA

  Hello

  I use LV 2009 with the new Toolbox FPGA and an NI PXI 7854R. I acquire an analog signal with a sampling frequency of 600kS / s. I need as the sampling rate for the processing of the data, but I also need the signal sampled with a much smaller, variable sampling frequency to a FFT.

  I've attached a picture to clarify, in a simple example, I'm looking for.

  

  I tried with the structure case only take each ' iht iteration, but did not get the expected results.

  Does anyone have another idea how to solve my problem? Of the, "Resampling" express VI in the funtion FPGA palette does not help me.

  Thanks in advance,

  Concerning

  Hello

  the connector for the analog input is a "shared resource", so you should he alone in your FPGA Code.

  Find attached an example that shows how to perform this task of analysis.

  Concerning

  Ulrich

  AE OR-CER

• Example rate vs clock rate cRIO

  I try to get my head around the difference in sample rate vs clock rate in the cRIO so I can explain it correctly my engineers in optics.

  I have a FPGA code that is just the Basic with e/s example.  Modules 1, 2 and 3 are NOR-9201 with a sampling frequency of 2uSecs.  The FPGA runs at 40 MHz or 25nSec/Cycle.  Read in the documentation of the loop While takes at least 3 clock cycles.  Estimate that other functions of the loop take about 7 clock cycles, the loop should run in 250nSec.

  This is faster that the 9201 - can enjoy.

  What does the FPGA?  He expects the sample at the end?  Takes the value of the previous sample?  Do we get a partial sample?

  Paul_Knight_Lockheed_Martin wrote:

  He expects the sample at the end?

  Yes - the loop runs in reality more slowly - he will meet at the level of the I/O node to the end of the sampling - time which is the sampling rate of any module is in the loop. For example, some modules analog high-resolution have read very slow time (like 52ms) then the loop will run at a rate of around 52ms (according to any other code you got in there).

  If you have the e/s high-speed digital, you almost definitely want to put it in a different loop at any analogue I/O so it is not slowing down your loop.

  I think that some modules are able to run in a single-cycle timed loop - in this case, the module will run in a single clock beat (for example 40 Mhz).

• Specified sample rate clock works do not

  I hope that I was right to post on this forum. I have a problem that I had not previously in the acquisition of data on a chassis 9172 cDAQ using a 9234 for 2 analog inputs and a 9219 for four thermocouple inputs. The 9219 is obviously not ideal as it has a rate relatively low sample (and I have a 9213 on the way), so I'll have to use to HAVE. ADCTimingMode to isolate channels on this module for "high speed" mode if I can get an adequate sampling for my load. The question that arises is that no matter what I do to specify a sample rate, the actual sampling rate ends up being 1651,61 Hz, higher than the features of the 9219, if I get an error. I tried to use the DAQmx property node to set the calendar and the clock sampling VI but neither work. The only source that I can choose is on board, but when I check the source used is cDAQ1Mod1/AI/SampleClock, even if I get an error when I try to provide as a source of sample VI clock.

  As it is, my VI runs despite this error and seems to produce accurate data, but the original problem is with long testing I will have unnecessarily large data sets unless I start to decimate my other data, and the secondary problem, it's that I can't get the program to run when I try to incorporate my task of counter. In this case, the error ends the execution and he acquires no data.

  I have attached my VI under the task of counter (I'm on 8.5 and have the coming upgrade as well), but also an image of a simplified version of the VI only try to specify the settings of a channel of AI. I get the same result with it. I'm a bit of a loss here because I've never had this problem before, and it seems that there is something beyond rudimentary that I'm missing, so I would really appreciate any help anyone could provide. Thanks in advance.

  
  

• 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.

• 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.

  
  

• myRIO sampling rate

  I'm new to myRIO and use it to measure sine wave (0V to 5V) of up to 10 Hz 20 KHz. I also quickly transformed of Fourier (FFT) of the signal measured in real time.

  Sideways FPGA of things, I try to keep things pretty simple, just read 2 channels of AI (connector B: AI0 and AI1), therefore potentially able to read each HAVE 250 kech. / s (as the unit has a capacity of 500kS/s). Does that mean this program gets a two analog inputs data exactly every 4 microsecond? If this is not the case, how can I make sure that the data is acquired through a fixed sampling rate?

  

  I realized that we can add to the FFT in FPGA function, but I wanted to manipulte the acquired data of analog inputs before it is sent to the FFT, which I don't know how to do now. Can someone explain me how do the arithmetic data (muliplication, division and so) on the acquired data and analog inputs to reducde the 12-bit resolution 10-bit to program FPGAS.

  Later, I created a myRIO program to read analog data 2 FPGA program which continues to turn in timed loop. In the program myRIO, the timed loop is configured to 1 MHz clock source type by a delay of 25 microseconds.

  This configuration means that the loop runs exactly every 25 microsecond?

  When I set up the less than 10 micro second time, myRIO has stopped working. Why is it so?

  Is it because myRIO cannot run as fast as FPGA?

  

  It is advisable to make the FFT of myRIO side analog data or FPGA?

  When I tried to do FFT using the power spectrum of myRIO side, he asked for waveform data. What I acquire is data analog. How can I convert in waveform data?

  If I read in the forum for help, I couldn't have the full answer to my doubts

  Discussions at the Forum I did reference:

  http://forums.NI.com/T5/academic-hardware-products-Elvis/setting-tick-count-in-myRIO-FPGA-software/m...

  http://forums.NI.com/T5/academic-hardware-products-Elvis/myRIO-aggregate-sample-rate/m-p/2707061/HIG...

  A lot of good questions here, I will try to answer as much as I can so as to offer a bit of advice.

  First of all, if you are looking to acquire data at a very specific rate on the FPGA, you'll want to use the Timer VI.  You are also going to use a FIFO of DMA to transfer data of FPGA in real time. A node read-write using as you do now means you'll run out of samples, or read the sample even several times.  The link below is a very good tutorial on how to do what I described above.

  http://www.NI.com/Tutorial/4534/en/

  Later, I created a myRIO program to read analog data 2 FPGA program which continues to turn in timed loop. In the program myRIO, the timed loop is configured to 1 MHz clock source type by a delay of 25 microseconds.

  This configuration means that the loop runs exactly every 25 microsecond?

  When I set up the less than 10 micro second time, myRIO has stopped working. Why is it so?

  Is it because myRIO cannot run as fast as FPGA?

  In general, you should not run a timed loop much faster than 1 kHz.  Using timed inside loop knots, you can monitor the real rate of loop during execution to see if f you meet your needs of the moment.

  The portion of your myRIO RT is slower than an FPGA in the sense where it cannot manage the rates of lines 40 MHz (he makes up for it by being able to work with much better pictures) and it is important to remember that it is just a computer.  The advantage of a real-time operating system, is that you have more control on the Scheduler, not that he is faster (less jitter, not faster code). There is more good reading below.

  http://www.NI.com/white-paper/3938/en/

  It is advisable to make the FFT of myRIO side analog data or FPGA?

  When I tried to do FFT using the power spectrum of myRIO side, he asked for waveform data. What I acquire is data analog. How can I convert in waveform data?

  I would say that it is generally advisable to treat your FFT on the side FPGA as long as you have the resources available, but for many applications probably little matter ultimately.

• NI 9237 sampling rate

  Hi all

  I use a module 9237 for certain measures of the load. My experiences last over time and so I'm generating a lot of data due to the minimum sampling frequency.  I can't define an external time base so I can lower my sampling rate to something easier to manage?  Even just a sample rate of 500 s/s would make a huge difference.

  Thank you

  Hi cannisbellum,

  9237 specifications frequency range of minimum data (fs) using the internal master time base is 1,613 kech. / s and external use master timebase is 391 s/s. The simplest would be to sample at 2kS/s and decimate your data by 4. This can be done by using 'Decimate 1 table D' or ".vi Decimate (continuous).

  Rates valid for the NI 9233 OR 9234 sampling and NI 9237 - http://digital.ni.com/public.nsf/allkb/593CC07F76B1405A862570DE005F6836?OpenDocument

  Best,

  CARISA

• Conflict to sample rate (specified real vs)

  I use NI 9234 to acquire my sensor data using labVIEW 8.6. I have been using labView for only the past two weeks, so please bear with me as my knowledge is so fundamental. I'm reading several channels over time. My problem is when I finished my VI, I discovered the whenever I change my bit in VI code rate, she even more fast (several sampling rate than what I said).

  I've never used a time base external with a data acquisition card, so it's a bit outside my field of knowledge. You may consult the manual to see if it's possible.

  Personally, I wouldn't bother. If you want a lower sampling rate 1,652 kHz, you could always decimating up to a lower rate. For example, if you enjoy at 1,652 kHz and then take each sample 16, you would then end up with an effective 103,25 Hz sampling rate.

  If you want to exactly 100 Hz you could make, because they suggest in the link and use the 'resample waveforms (continuous) .vi"to re - sample data.

• Specific sampling rate?

  So maybe this is a stupid question, but I need to know because I train for a specific sound. Is there a way [to logic] to shoot/change of a certain frequency sampling rates. I can imitate the sound I'm looking for with a low pass filter, reverb and a distortion. But I don't want to 'emulate', this sound, I want to create. Then I can put my own effects and play with it like I want to. If I have to use a bunch of effects to make it sound like I want that also the addition of said effects remove the sound and sound horrible. as to where pulling the sampling frequency of the high frequency and no downs will make me THE noise that I need and always allow to add nice effects to make MY sound instead of someone else. I hope you know what I mean. Let me to you specific real once more. I want to pull or carry a certain frequency sampling rates for a sound under water. I don't want to use filters to make the sound. So can you please help me. I invited everyone locally on how to do it and nothing works. Also if this is not possible in the logic of tell me if there are third party plug ins or maybe even a different DAW that could do like komplete Kontrol or audacity.

  Effect under water

  See if this thread is helpful at all...

• Sample rate Max USB-4065

  Currently, I am trying to log readings of DC voltage with an AA battery in an ASCII using LabVIEW 2009 of SingalExpress file and the USB-4065 digital multimeter (DMM). I have two stages:

  (1) acquisition of Signal > voltage DC using DMM

  -resolution 4.5 with 3.333333E the value-5 sampling period

  2) save in ASCII

  -The value to add to the file, delete the file after each race

  Faster reading, I can get is a data point written in the ASCII file every eighth of a second.

  Furthermore, I am new and software OR LabVIEW, the LabVIEW SignalExpress software I have is only for evaluation as it was included in the CD of the driver for the USB 4065 DMM.

  1. Max (30 000 samples per second) sampling rate is only achievable by a LabVIEW VI?
  
  
  2. Don't I have the wrong settings for DMM step?
  
  
  3. Is it because I haven't activated SignalExpress and am only using the evaluation version?

  Thanks in advance for any help!

  Hello Lukos,

  You are assuming that you need access to lower level functions in order to obtain the higher sampling rates. In order to get these speeds, we need to disable some settings that are not accessible via Signal Express. You can create a VI and then use a step VI call in Signal Express to stay in the same environment.

  Kind regards

  -Travis E

• 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

• DMM (NI 4070), how to correctly set AC Freq (bandwidth) by the sampling rate

  using a NI4070 multimeter and I see the max connection is 300 kHz by respect it.  But I don't understand how to set the min and max, acFrequency according to the sampling frequency or speed reading.

  6 1/2 digits resolution, the speed can vary from 0.25 s/s to 100 s/s and this range corresponds to a lower end on the connection (minimum acFreq) from 1 Hz to 400 Hz.

  (Q1a) - is the playback speed, controlled by the minimum setting of IviDmm_ConfigureACBandwidth?   or vice versa?

  Otherwise, I do not see how to control the rate of reading or the sampling frequency.   IviDmm_ConfigureMeasurement only allows you to control the range and resolution.

  (Q1b) - is there a way to directly control the sample rate (digitizer) or playback speed (dmm)?

  (T2) - the upper limit of the bandwidth of AC always seems to be at 300 kHz... is there still a reason to reduce this maximum value?

  (T3) - Finally, unlike the traditional niDmm function, the resolution via the IVI configuration should be passed as absolute value; does directly when number of digits and the beach?   For example if I want to 6 1/2 digit to 300V range, I guess that by the specifications that the resolution should be set at 0.001 V... followign, if I want 5 1/2 digits to 1V range, the resolution should be set to 0.00001 V?

  Hi Rjohnson,

  I'll try to answer your questions as best as I can:

  Q1A.  The ConfigurACBandwidth function is used by the driver OR DMM to calculate the good aperautre for the measure.  So yes, by adjusting your minimum frequency, you will affect your reading speed.

  Q1B.  Your reading rate will depend largely on your measuring cycle.  To get a fast measuring cycle, there are a few things that you can adjust.  You can programmatically control your time aperature, as well as your time to settle.

  Q2. I can't find a reason to change. This parameter is only used for error-checking and verifies that the value of
  This setting is less than the maximum frequency of the device.

  Q2B.  I think what you say is right, but I'll need to check on that - I'll let know you as soon as.

  Hope that helps.  "" "I would recommend checking the explanation of the Cycle of the DMM measurement in DMM help' devices ' NI 4070" DMM Measuments "DMM measurement Cycle.

  Take care!!

• sample rate real vs min sampling rate

  I'm sure it's an obvious answer, but here goes.

  I have a USB-5132 ' scope and using niScope horizontal configuration Timing.vi I put, among other things, the minimum sampling rate. In my case, I chose 20 MHz, which of course gives a sampling of 50 ns period.

  I use niScope reading (poly) .vi with the WDT variant to read waveform data.  I noticed something very strange - waveform limit testing throw error 1802 "signals have a dt of different values '-if I put a waveform components unclusterizer Get on the wire of waveform and looked at the value of dt of the wave." He told me that my dt is 40 ns, which of course is of 25 MHz. I also plead for only 2000 samples.

  So what causes this shift? Why the digitizer does not accept everything just my desired sampling frequency?

  Austin Walton wrote:

  Andy,

  The setting of minimum sampling frequency is the frequency at which digitized
  the samples are stored, expressed in samples per second. This setting is rounded
  up to and including the next legal collection that supports your device.  Ownership of the actual sampling rate calculates the actual sample used for the acquisition rate.

  Unless you specify another source of the clock, the digitizer uses an internal oscillator as clock source.  For the 5132, this oscillator is clocked at 50 Mhz.  When using the oscillator internal as the sample, the digitizer clock source can use versions split to the bottom of this clock, for certain sampling frequencies are not possible.

• How to create a waveform from an array with arbitrary sampling rates

  Hi I know that sounds a little silly,

  Suppose I created a simple table of figures DBL with a structure For, Say size 16. now, I want to create a waveform DBL with these 16 numbers at an arbitrary sample rate. so if I use 1 kech. / s to the sampling frequency, I want to have a waveform with a duration of 16 milliseconds.

  Please help me, I need it too

  TNX

  Hello

  You must use the wave to build function as shown here: http://zone.ni.com/reference/en-XX/help/371361G-01/lvwave/build_waveform/ . Wire you your Board at the entrance Y and then wire the dt of entry in your sampling rate.

  -Zach