Two signals 1 d

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• Two signals to two graphs of waveform

  Hi all!

  I had some problems with my data acquisition software.

  I got two signals and I show two signals to two different graphic signals.

  How to separate the signals?

  There is an entry called "table". Just this thread in the 2D DBL table. Drag the bottom of the table Index down so that you have a second output sub-table. Wire of your graphics. Fact. No need to plug anything on the index entries.

• 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

• Add two signals different dt

  Hi, I try to achieve the function Sum (+) and Sub (-) with the participation of waveforms, I know the problem and the different dt when dt is the same the smooth executing operations but I want to achieve something like this Waveform sum Figure 1 as you can see if two signals with different frequencies are added between them the result looks like Figure 1 , but with the same dt different frequency is not calculated and the amount always show that the two signals have the same frequency. How can I realize the amount similar to that in Figure 1? Thank you all

  Hello Silversky,

  It seems you want to do something like that...

  But the figure referenced never mentions the signals with different dt! Simply to create waveforms with same dt in the first place...

• How can I synchronize two signals in Labview?

  The first signal is a pulse index which gives the position of a reference point of the wheel (= 1 for 0 ° and signal = 0 for 1-360 °), and the second signal gives the total force meeting the wheel. The two signals have different sampling rates high. The first signal is always 360/rotation, but the second signal varies from cycle to cycle based on how fast the force is changing. The signals are in the form of two columns of numbers in an excel spreadsheet.

  I would like to do such as Labview at the exit of the angular position of the reference at the time of the cycle where the wheel knows the maximum strength in degrees. Can anyone suggest a vi or a method that I might be able to use for this task? I am new to Labview, so any help is appreciated.

  Hi Westerman,

  I have a little trouble to understand the basics of what you're trying to do. A little more details would be very helpful pointing you in the right direction. If you want to align the timestamps/reference of the two signals time?

  I've included a link to a document that describes generally how encoders (I guess that your pulse index indicates that you are using an incremental encoder) can be used in LabVIEW.

  http://www.NI.com/white-paper/7109/en

  You should also try the search the forums for questions relating to the use of a rotary encoder in LabVIEW. I was able to find several with the included code example.

  Feel free to provide us with a few details and we'll help guide you.

  Andy C.

  Technical sales engineer

  National Instruments

• How do I display two signals graphic multiplot

  Hi, I am currently working on a LabVIEW program that requires me to display two signals measured by two current using MyRIO sensors OR. I am facing problems displaying two signals on dashboard of data, I know how and what should I log in the block diagram Front Panel of LabVIEW so that both signals, measured by the current sensors can be displayed on the dashboard of data?

  -Introduction to LabVIEW: http://www.ni.com/getting-started/labview-basics/ and http://www.learnni.com/
  -Check the labview\examples\general\graphs\charts.llb for examples of the waveform card: https://zone.ni.com/reference/en-XX/help/371361J-01/lvconcepts/types_of_graphs_and_charts/
  -Examples: http://digital.ni.com/public.nsf/allkb/21E8163F259DA2058625703B007511AA , https://decibel.ni.com/content/docs/DOC-40940 , and https://decibel.ni.com/content/docs/DOC-5574

• Time scale does not properly after separation of the two signals of virtual channel

  Hi all

  I have a problem when I use a virtual channel with two analog inputs. I'm cutting the two signals into two separate tables of waveform, as shown in the attachment. The two signals seem to be reading very well, the problem is that the time scale (x-axis) begins to act on the strange. Seconds displayed time seems to keep jumping up and down at a high frequency, resulting in the two signals of displayed does not correctly in the table of waveform. Could someone please try to help me? Any help would be greatly appreciated!

  Thanks in advance.

  Try to acquire a signal with first time information. You can replace the DBL 2D with a data type of 1 d wave. You don't need this code extra silly - just a function of Board Index to get the separate channels.

• 200560 error during the generation of the two signals of AO

  Hello

  I am trying to send out two signals and I get error 200560 to "wait until done" vi.

  I was wondering if there is no solution for this problem.

  BTW, the vi is attached.

  Thank you

  Pooya

  You have your clock set to continuous samples. I don't know if you can use 'Wait until what' If you the task will never happen. Set your click on over and see what happens.

• USB-6008, how to calibrate two signals are equal entry?

  HI all, I use NI USB-6008 and evaluation of labview 8.5, using the daq assistant.

  1st quarter) to calibrate the two input voltage signals become equal?

  Q2) I used the comparison for example function: not equal.  When the two entries get value not equal, how to output of 0-5 v output?

  If someone need more information to help me, I can provide.

  Not sure at all what you mean by "0-5 v output to the output. Want you the difference between the two inputs to output?

  In addition, two input signals will probably never equal. It's just not something that exists in the numbers floating point on a computer. You must subtract one from the other and uses in the range and force the function to determine if they are close enough.

• Two signals interfering with each other

  Hello

  I have a problem with a trace of pressure and a vibration sensor. I have a card PCIe - 6341 DAQ. I connect my pressure signal to a channel (say ach0) and I connect the vibration to another analog channel (say ach7).

  In labview, I use an assistant DAQ. When I use it to sample only one of the signals, there is no problem. If I add two channels in the configuration dialog box, the signal pressure becomes superimposed vibration signal.

  Analog signals entering data show no interference (checked with an oscilloscope). I suspect that what is happening inside the data acquisition card.

  Any ideas why this happens?

  Thank you

  Masoud Mashkournia

  Hi Masoud,

  It seems that you see 'ghosts' on your channels.  The 6341 multiplex via the analog inputs.  Therefore, if you are scanning between high voltage and low voltage, especially when you use CSR, you can see ghost images if the signal from the previous channel file completely or have a path to the ground.  Here is a good article from the knowledge base that describes ways of eliminating this remanence.

  I noticed that you use the configuration of the CSR on your DAQ Configuration Wizard.  Try using a differential input configuration.  This can help eliminate unwanted common mode voltages.  In addition, you can try place a middle way in scanning which is connected to the ground at AIGND in the DAQ command scan.  This can help with the mass of the previous signal.  Most likely, you will want to scan in this order: pressure, ground, vibrations.

  Please let me know if it helps.

  Best,

• record two signals - sinus 20 kHz in 1 minute - rate of 400 samples

  Hello world

  Is it posible to save two sinusoidal signals in one minute with samples of rates. How I can achavied this. Its a lot of samples. When I tried, programe out with error message saying that "attempted to read samples that are no longer available. Required sample was previously available, but it has since been crushed. "When I increase the number of samples to read there are of the same (outgoing). When I read all the samples it reads to me that some elements ferst save a minute and rest of the signal are declares. In one minute programe will be saved 12000000 samples and I guess for a signal due to 400 kHz rate. To save, I use tdms blocks (open, writing, relatives).

  Whot I'm doing wrong? Please help.

  Marek

  There are a few things I can suggest:

  1 take a look at the following article:

  Why should I get error-200279 of my DAQmx Read VI or the property node?

  2. you must have an architecture of producer/consumer when you're reading in these high sampling frequencies and trying to save all the data in a file. My suspicion is that it may cause the problem that you are facing. You can access the model for the architecture of producer/consumer navingating the file-> New... in LabVIEW. Take a look and let us know if you have any other questions.

• Audition performs the subtraction of two signals?

  I'm just surprised that this feature is not widespread among all sound editing software out there.

  Just as we are able to perform the SUM of 2 channels (i.e. mix), we should be able to perform their SUBTRACTION.

  TIA,

  -Ramon

  Travis,

  It may be late to answer you, but yes you can. Simply to "reverse" a copy of your file wav and "Mix dough/overlap" with the original. The result will be 0.

  Now if you have two different recording, one for an A + B signal and the other with report to subtract B which is a bit more complicated because the two recording received these signals of different paths. This is likely to lead to the difference in frequency response and phase. Lets assume that it is not the case, you will first need to align the two record sources. You can do this in audition 3 using the convolution product, as shown in this video:

  How to make the audio loop perfect using Adobe Audition - YouTube

  Then, reverse the recording with the B signal and 'Paste Mix' together.

  You can do more research on adaptive filtering and the RMS, LMS filter if you want to compensate for the different audio track.

  Good luck!

• Find the time delay between two signals

  In this code, I sent you a pulse in the acquisition of data using labview. The pulse triggers a thermistor to another analog input input data.

  I want to find the delay between the time of the positive edge of the switch, and the exact time of the DAQ begins to take in the signal of the temperature probe.

  I enclose the code below.

  Thank you.

  Hey,.

  Here is a link to some information about the sources of clock on the FPGA.

  http://digital.NI.com/public.nsf/allkb/94CE338CC80ACF008625791400516BAA?OpenDocument

  Hope this helps

• : The TWO SIGNALS DRAWING: need converter

  Hello

  I just need to shoot 2 signals at the same time with index range x [-1.. 1] by 0.1

  the first signal is tan (x) hyperbolic function and the second signal is my Function

  I think I need a converter!

  concerning

  m, s

  mangood wrote:

  I want to draw the ideal tanh with my function at the same time to see the error as below with x

  Something like that?  I simply called the VI facilitated in a loop FOR, autoindexed the outputs and created the graph plots.

  

• The best way to draw the difference of phase vs. time of two signals

  I have three channels (time, force, displacement) of approximately 1 000 seconds of a sinusoidal test load test data (sampling rate was 100 Hz).  I would draw the difference in phase between the force and displacement (perhaps using a second window 30) according to time.  I tried using a few different analysis functions, but I get what looks like random noise (phase difference between force and displacement is very small and the difference in amplitude is very fantastic - 4 orders of magnitude).  Any suggestion would be appreciated! -Jim

  Hi Jim,.

  The phase channel resulting, that you get with the function FFT DIAdem is in the frequency domain.  If you select a channel data and time in the FFT dialog box, you will get a frequency channel that results as well as the Phase channel resulting.  If you select only a weather channel of waveform data in the FFT dialog box, you will get a Phase of waveform frequency channel resulting.

  Brad Turpin

  Tiara Product Support Engineer

  National Instruments