myRIO sinusoid frequency errors

Similar Questions

• Generation of sinusoid frequency accurate FPGA

  Hello everyone,

  I have a myRIO and I want to build a lock in the amplifier. To this effect, I need excite (in fact the driver laser) laser with a certain frequency, in a case 32754 + to 1 Hz. This signal must be a square wave. I need a sine and a cosine with the excact same frequency that I use to turn on the laser. But the sine and cosine do not have to be sent outside the FPGA through a port analog or digital.

  To summarize, I have need of a square wave, sine and cosine with excactly the same frequency. Only the square wave is sent through an analog port. (I use the "square wave generation.vi")

  This works very well for example 4212 Hz. But 32754Hz can't be represented pretty good by a 40 MHz clock (a lot of jitter). To this effect, I thought to use a Schmitt Trigger.

  Finally I come to the point! I use the "generator.vi of sine wave' on the FPGA.

  Can I output a sine wave signal with any frequency I want to use this VI, if right of Nyquist is hurt? As this VI uses DDS I think that Yes, can anyone confirm this?

  I only ask, because the sine wave will be converted into a square by the schmitt trigger signal and should always have the same frequency that it represents in the FPGA.

  Kind regards

  Slev1n

  Slev1n wrote:

  Hey, JLewis,.

  1, how can I calculate/derive the resolution?

  2, the size of the LUT or also the resolution of the amplitude of the a influence on the resolution of frequency?

  1. the resolution only depends on the accumulator and clock rate, e.g. 40 MHz / 2 ^ 32. The rate of the clock increases the resolution of the average frequency of DDS, but will negatively affect the jitter due to the clock period. In your case, it seems that you are more interested in the resolution of frequencies without jitter, which are those for which the clock frequency is an integer multiple of the frequency, for example freq * k = 40 MHz. You can play games with clocks derived from hitting a specific frequency, but in general most of the frequencies will be free of jitter.

  2. the other settings do not affect the resolution, but affect the phase noise and/or quantification. For your application, I expect that phase noise is the biggest problem and is affected by the LUT, the interpolation option size and samples/cycle (IE, the rate of the loop). Quantization noise is affected by the output data type and amplitude (otherwise the range). You will get a filtering via the D/A conversion and the Schmitt trigger, so it is difficult to predict how much of a concern these parameters will be for you.

  You can see the Xilinx DDS generator (on the pallets of Xilinx IP integration). He has a few more options as the dithering phase and a 48-bit accumulator. On the theory and the effects of various parameters of their documentation is excellent: http://www.xilinx.com/support/documentation/ip_documentation/dds_compiler/v6_0/pg141-dds-compiler.pd...

  I hope this helps!

• Diagram of frequency domain

  Hello world

  I'm sorry if the question may seem stupid, but how can I draw the sinusoidal frequencies on the x-axis and the corresponding amplitude on the y-axis after that I could achieve fourier transformation?

  Thank you very much in advance for any advice.

  Andrea

  Use a graph of a waveform.

  I'm assuming that your FFT gave you a data table, a F0 and a dF.

• Why labview programmers use 10.1 the default frequency instead of a same 10.0 Hz?

  It was an issue that was raised during the lab class and no one has an answer for.  Any ideas?

  I call it the wagon wheel effect.

  In the old westerns, whenever a wagon with a Ferris wheel to rays rode by the camera, sometimes the wheel would look like it rolls slowly forward, sometimes slowly propagated backwards, sometimes it would look as if it was stopped.

  It is a function of the frame rate of the camera over the period of the cycle of the spokes of the wheel.  If we spoke (or more) offers exactly the right distance between a frame of the movie and the next, it would look like the wheel had not moved at all.  If he moved a little further than the distance from rotation of we talked, it would look like it rolls slowly forward.  If the cart is a little slower, then it would move only less than the distance of a spoke and he would look like the wheel rolls backward.

  Same thing with having a periodic waveform (every bump of the sine wave is a spoke of the wheel) and a number of acquisition of samples and data rate equal to a whole number of this period (essentially the frame rate of the camera.)  Wagon wheel always rolls forward.  The sine wave is still oscillating.  But according to the rate of acquisition compared to the wave sinusoidal frequency gives a different appearance to the appearance of this sine wave on the chart.

  Experiment and give it a 9.9 Hz sinusoid, you will see that it seems to move backward.

  So I think (and this is only a guess) is that whoever designed the express VI gave it a default value of 10.1 Hz to visually simulate on the graph of the sine wave motion.

  It doesn't really matter what they chose by default as it is to you that the programmer LabVIEW to change this default setting (whether in the express VI or the wiring in a value) to something that makes sense for your application.

• Align the two signals and measure the Phase Shift

  Hello

  I do an experiment in which I use the NI USB-6221 DAQ card. The jury is able to make 250 k samples/second. I want to measure two voltages in a circuit and find the phase shift between them at frequencies between 1 and 10000. First I ouputted a wave sinusoidal frequency variable through the Commission and applied to a test circuit. Then I used the Board to measure the two tensions consecutively (thus reducing the maximum sampling frequency at 125 k). I used the signals align VI and measured the two phases and then calculates the phase shift (VI attached in Phase 1). It worked well for the test circuit I built in which the phase shift went way logarithmique.20 degrees ~84.5 degrees and then stabilized. At frequencies above 5 000 Hz phase shift must have remained constant, but it varies more or less 1 degree. When the phase shift is 84.5 degrees, present a degree of variability is not particularly explicit. When I asked my program on the circuit that I really wanted to measure, the phase shift went from-. 5 degrees up to about 1.2 degrees. The change in the values of phase shift at high frequencies (> 3000) was environ.2 degrees. Given the small phase shift, this variation is unacceptable. Now I tried to use a sequence to each blood individually (increase the maximum sampling frequency to 250 k) and then align the two signals and measure the phase of each shift. When I use align it and re - sample Express VI to realign the two signals, I get the message "error 20333 analysis: cannot align two waveforms with dt even if their samples are not clocked in phase." Is it possible to align two signals I describe here? I enclose the new VI as Phase 2

  Matthew,

  I think I have an idea for at least part of the problem.

  I took your program data and deleted stuff DAQ.  I have converted the Signal on the chart control and looked then what was going on with the signal analysis.

  The output of the Waveforms.vi line has two waveforms, like the entry.  However, arrays of Y in the two waveforms are empty!  It does not generate an error. After some head scratching, reading the help files and try things out, that's what I think is happening: the time t0 two input signals are 1,031 seconds apart. Since the wavefoms contains 1,000 seconds of data, there is no overlap and may not align them.

  I changed the t0 on two waveforms are the same, and it lines up.  The number of items in the tables is reduced by one. Then I increased the t0 of 0.1 seconds on the first element. The output had both greater than the entry by dt t0 t0 and the size of the arrays was 224998.  Reversing the t0 two elements shifts the phase in the opposite direction.

  What that tells me, is that you can not reliably align two waveforms which do not overlap.

  I suggest that you go to 2-channel data acquisition and that it accept the reduced sample rate.  You won't get the resolution you want, but you should be able to tell if something important happens.

  You may be able to improve the equivalent resolution by taking multiple steps with a slight phase shift. This is similar to the way that old oscilloscopes of sampling (analog) worked. Take a series of measures with the signal you are currently using.  The make enough average to minimize changes due to noise. Then pass the phase of the signal of excitement to an amount that is smaller than the resolution of phase of sampling rate and repeat the measurements.  Recall that I calculated that for a 5 kHz signal sampled at 125kHz, you get a sample every 14.4 degrees. If shift you the phase of 1 degree (to the point/mathematical simulation), you get a different set of samples for excitement.  They are always separated by 14.4 degrees.  Take another series of measures. Transfer phase another degree and repeat.  As long as your sampling clocks are stable enough so that frequency does not drift significantly (and it shouldn't with your equipment), you should be able to get near resolution of what you need.  The trade-off is that you need to perform more measurements and may need to keep track of the phase shifts between the various measures.

  Lynn

• 50mV peak output of sine similar, f = 10 kHz

  Hello!

  Yesterday, I found that when I create an output signal sinusoidal similar (with a program labview or M & a test panel) the sinus has a 50mV peak when it changes sign (+/-)

  I use a USB-6212

  LabVIEW 8.6

  example of frequency: 200kS/s

  sinusoidal frequency: 10 kHz

  The peak is always there to 1000 Hz (stil 50mV), but I do not see for the frequency of 10 Hz.

  The advanced amlitude does not change for the Amplitudes between 1V to 10 mV.

  I see the same glich on AO-0 and AO-1, and it's always when the sinuses = zero.

  You know: ' what is it?"and the most important: what can we do about it?

  I have attached a picture of the vertices for a sinus with amplitude 10mV.
  

  Application of a filter to exit the peak would be my last resort, but this does not seem like the way to go.

  Thank you very much

  Higgins

  This glitch (epi) is typycal for some (simple) CAD models. A simple RC filter can help. Bonny Baker wrote that an article in EDN to this topic and an article on this topic or is also to ni.com somwhere...

• Multi-multifunction-Synch rate HAVE AO

  Hi all

  I'm new to Labview and these tips.

  I work through the AI Multi-multifunction-Synch-AO example as found for example NI Finder and I was wondering what difference between it the "rate of generation of update" output "Sample clock" and the sampling rate is on in the "sample information" of the "core generator.

  My first thought was that first of all, a control material and a second control of the software, but I find that when the two are adjusted against each other, my changes of sinusoidal frequency, even when the frequency parameter is left unchanged.

  Thanks in advance.

  Hi currentenglish,

  Generation of update rate attached to the "sample clock" indicates the rate at which the jury will clock samples.

  The "sample information" is used by the software to generate a waveform appropriate considering the rate of the material.  If there is an incompatibility between these two values, you will have a different frequency than you expected.  For example, if you generate the waveform into thinking that the sample clock is 1 kHz, but it's really only 500 Hz, the generated waveform will be half the frequency you specify.

  You should connect the rate of generation of update in the sampling information to ensure that they are always the same.  I'm actually a little surprised that this example of shipping is already this.

  Best regards

• Time of camera and Piezo

  Hello

  I'm trying to control the movement of a piezo transducer and the acquisition of images from a camera with a precise timing. First of all, I'm driving the piezo of sinusoidal frequency, f. second way, I want to acquire images with my camera at a frequency of 2 * f. i.e. I want when my piezo voltage is the maximum and minimum values.

  I'm relatively new to LabVIEW but I figured out how to control my image acquisition and piezo independently. However, I am running out of problems with synchronization when I try to do two things in unison.

  For now, I use a loop and the 'Simulate Signal' function to generate my output voltage to my piezo. Then I have a second loop in parallel to drive my camera acquisition. I went to some effort to ensure that the two loops to begin to run at the same time by using "appointment". I have my current VI attached. It sort-of work, but I don't know there is a better and simpler way to do it. If for some reason, one of the loops is running a little out of time, the curls will fall out of sync after several iterations. I'm just saying as I go about the process of how bad do not use single loop? I've thought about it, but I don't know how to implement it? If I put the loop of image acquisition in the loop of piezo, is not the process of acquiring an image high when my piezo?

  If someone could offer advice that would be great!

  Thanks in advance,

  Paul

  Hi Paul,.

  Here is my attachment in LabVIEW 2010.

  Kind regards

• 1908WFP off-limits

  Hello

  I have 1908WFP screen LCD dell and HP xw 4600 workstation with video card ATI fireGL v3400. now the problem is, after loading windows a frequency error output is shows and none work key and I have no access to desktop menu I can change its desired resolution and frequency as a parameter. any solution?

  PIC of the error:

  

  You must have had another monitor connected to this computer, and set the resolution to something higher to 1440 x 900. You will need to reconnect this monitor and change the windows desktop of 1440 x 900 resolution. Then disconnect and reconnect the 1908WFP.

• frequency corresponding problem with myrio!

  Currently, I am working with myRIO and Labview 2013 to generate sinusoidal PWM signals.
  When I created 'analogue output' tab myRio and connected to the Oscilloscope, oscilloscope waveform could not show me the appropriate frequency combined with a frequency that I gave in labiew. Is there a relationship between the frequency of "the"(myRio tap) of analog input between real-time rate? ". Otherwise, is it certainly possible to calibrate the frequency in labview? Please help me!

  
  

• Error: Bluetooth + WIFI works within the same radio frequency

  When the wirelessLAN is open and then press Fn to open bluetooth this error pops up, please help me to solve this

  ERROR:
  Opearte to device Bluetooth (TM) and wirelessLAN in the same radio frequency range and may interfere with each other.
  If you use bluetooth and wireless LAN devices at the same time you occasinally network performance optimal experience or even lose your network connection. In this case always stop your operation of LAn wireless or bluetooth.

  Hi mate
  It is simply to solve. You must use the BT or Wlan.
  So, if you use BT connection, please turn off the WiFi and if you use Wlan, then disable the BT

  In order to disable the WiFi or BT please use the Fn + F8 key combination you press this several times until the option has been disabled.

• Myrio NOR in the Eclipse IDE: could not load library error NiFPGA

  Hello! I just started working with the myRIO NOR model 1900, using the Eclipse IDE. I tried build and run some of myRIO NI C examples by following the procedure described in the document 'C_support_for_myRIO_User_Guide' given by NEITHER. It builds without any errors but get this error when I try to run all programs:

  "ERROR:-63194"
  Failed to load NiFpga library! »

  It would really help if someone could suggest a solution for this problem. Thank you

  Hi ANJ123,

  Try to go through the following links.

  http://www.fixerrorhelps.com/fix-PC-error/how-to-fix-NiFpga.dll-error.html

  http://www.dllplus.com/fix-file-error/NiFpga.dll.html

  https://decibel.NI.com/content/docs/doc-31772

  See you soon,.

  ROLLAND

• myRIO install error TARGETDIR is undefined table incorrect directory

  During the installation of the software for myRio, I bought Aug 2014

  Disc 1 shows the screen of LabVIEW 2013, and the folloing popup error message

  TARGETDIR is not set, the Directory Board seems incorrect.  Abandonment

  I use windows 7 on this laptop, but received the same error message on my windows laptop 10.

  Check where you have the installation program located.  Here's a knockout who explains how to fix this problem:

  http://digital.NI.com/public.nsf/allkb/24E09BDC314EB93A8625758D004ECBC6?OpenDocument

• myRIO VISA error-1073807192

  Hello world

  My problem is this: my myRIO can see successfully a Hokuyo URG - 04 LX module that I have connected to the USB host port. However, when you use VISA resource open, I got the following error:

  -1073807192: VISA: (Hex 0xBFFF00A8) is denied access to the resource or to the remote machine. This is due to the lack of sufficient privileges for the current user or the machine.

  KBs online suggest that it is a security issue to do with the address IP, but MAX shows the myRIO security settings allow communication on all ports.

  So, at this point, I'm stumped! Does anyone have any suggestions?

  Additional information:

  The myRIO detects not that kind of default device, I had to follow this tutorial to learn first how to get LabVIEW to recognize a connected device ttyUSB as a FTDI chip and then deviate from the tutorial slightly so that it supports the class of device Communication USB (ttyACM), which is the type of device class the URG - 04 LX adheres to.

  The code I used is:

  In the file/etc/mdev.conf, under #typical of devices, I added the line:

  ttyACM [0-9] * root: ATS 666

  In etc/rc5.d/, I added the S10SetLnUSB file that is provided in the tutorial, except all the entries pointing to ttyUSB were replaced by ttyASM:

  #! / bin/sh
  #echo '==> SymLnk ttyACM0 creation. "
  #ln s/dev/ttyACM0/dev/ttyS2
  n ='ls

  / dev/ttyS * | kind | tail-1 | tr ' ' ' | AWK ' {print $2} "
  num = 'expr $n + 1'.
  ln s

  / dev/ttyACM0 ' / dev/ttyS$ {num}.

  Finally, the tutorial recommends using this command to recognize the addition of the script:
  #chmod a + x /etc/rc5.d/S10SetLnUSB

  
  At this point the myRIO can successfully see the connected device.

  I reformatted back to the standard driver implementation myRIO plus all additional drivers additional NI-VISA (5.4) such as the passport of USB of NI-VISA. It turns out that after all debugging, all you have to do to get a class of devices of Communication (CDC, ttyACM) module to get recognized within LabVIEW RT is to do the following:

  1. Download your LabVIEW RT remote target visible in MAX.
  
  
  2. Plug the module USB to the USB of your target remote host port control.
  
  
  3. SSH in LabVIEW RT.
  
  
  4. Make sure the device you are using is a CDC. You can do that by typing the command #dmesg, and get a response that looks like this:

     [173.342694] usb 1-1: new USB full speed device number 2 using xusbps-ehci
     [173.635010] cdc_acm 1 - 1:1.0: ttyACM0: USB ACM device
     [173.652955] usbcore: registered new interface driver cdc_acm
     [173.652977] cdc_acm: driver model USB abstract control for USB modems and ISDN cards

     Your real answer my vary slightly.

  
  
  5. Run the command #rmmod cdc - acm. If the command line returns does not return a response, the device driver has been deleted successfully.
  
  
  6. Go to NOR-MAX on your host machine and refresh the list of devices and Interfaces for your remote target. The material should now appear.

• Error 200077 (frequency) and 200452 (task control loop) error occurred DAQmx create calendar Source.vi

  Hello

  I'm trying to control the timing of a timed loop. So far, I have tried several approaches via the software and which worked very well except the time loop in some missed cases 1-2 Ms I want to make sure the timing is right. I tried to provide an external clock through the acquisition of data I. The system I use is NI USB-6212. It has two counters and DIO and AIO, but I keep getting errors. I tried two different approaches. One was to use directly the game 'DAQmx create calendar Source.vi' in frequency mode, and when I did, I got error 200077. Then I found a post of somone saying that sometimes it is not possible and an alternative method is to use the same vi but set task of loop control mode. This one gave me Error200452. For this one you will see in my attachment the suggestion was to use an AI then the moment of him and then use this task for Creat DAQmx synchronization Source.

  I don't know what the problem is or if I need to put something differently.

  Please let me know if you can help me with this.

  I'll try to continue to work on that, but if anyone of you a suggestion I'll be very happy to consider the issue.

  Thank you in advance,

  Best, Massimo.

  Massimo,

  In my view, the errors that you see are the result of your hardware USB-6212 is supporting the functionality of the task control loop.  I have a M Series PCI card that is capable of operating both of your screws attached without problem (although they still +/-1ms variation on occaision).  When I try to use a USB-6212 simulation, I get the same error codes that you do.  Unfortunately, it's just a case of a lack of equipment.

  Kind regards