Reading data series acquired a data acquisition

Similar Questions

• The reading of data acquisition via tcp

  Hello

  I am building an application that controls an acquisition of data via tcp.

  I have a JAVA program that communicate with labview, give a command and data acquisition starts. (So, I read the correct Java data at Labview)

  My problem is if I try to read data acquired by data acquisition (continuous sample 1 k samples), I've read strange values.

  I transform of double values in the string and send it via tcp.

  How can I read it in Java? What type of socket should I use? What is a rate problem?
  I also tried to transform small/big-endian byte order, but it does not work.

  I enclose a sketch of this part of the application.

  Please help me, I try for 2 weeks!
  Thank you all...

  I find the solution in the lavag forum.
  I post here, if it can help someone.

  http://lavag.org/topic/16359-sending-LabVIEW-data-via-TCP/page__pid__99983#entry99983

• Data acquisition reading incorrect when you use a loop

  Hello

  I wrote a simple VI (00, 01, 10, and 11) output to a circuit connected with 4 resistors. Based on what value the ciruit receives, it passes current through a particular resistance. It is again entered in Labview and traced.

  The problem is when I send a particular value (i.e the 00, 01 and 10 and 11) and get that back, it's okay. But when I send and receive the consectively connected via the loop counter, they are incorrect (not synchronized with the number of the loop).

  I made sure that circuit works very well. It has something to do with the loop synnchronization, reset, value compensation, etc. can be.

  Please Guide...

  Change your DAQ assistant that reads to be 1 sample on request.

  Right now it is set for continuous samples.  And 10 samples at 10 Hz.  Then it runs and starts.  The next iteration, you send a new digital out, but the wait for 4 seconds.  When you read again, you get the next 10 samples that are put into the buffer of data acquisition, but now 40 samples have actually entered the DAQ buffer.  In time your DAQ buffer will be finally complete and raise an error.  In the meantime, you will continually read data continues to become more tainted by the iteration.

• Input module of data acquisition can be read by two or more LabVIEW vi at the same time % 3F

  I use the DAQ palette in LabVIEW to read the virtual channels of the input data acquisition module. I've done several VI who read many entries of three modules of simulations. The problem appears when I run two or more VI´s reading entries from the same virtual module (for example. first.VI module 1 input ai0 and second.VI bed ai0 entry module 1 bed), when this happens the next errors are shown:

  Error-50103

  Platform AND Services: The specified resource is reserved. The operation could not be performed as indicated.

  and

  Error-200022

  Resource requested by this task has already been reserved by another task.

  It's worrying because I want to get the DAQ chassis and some modules, but if this problem is present with physical equipment my application may be unnecessary. This means that entry module only can be read once at the time?

  I m using global variables in each Subvi to share data with main VI, however, I found the solution in a different way... I just changed to single channel and dbl sample playback mode, so I Don t need to clean up the task of reading in my subVI´s, the zeros isn´t problem here, and the six subVI´s work at the same time!

  Thanks for the tips!

• How to read data from the unit to acquire data with LabVIEW

  Hello everyone, I'm new with LabVIEW and I need help. How to build LabVIEW program to read and store the data acquisition unit temperature data. the data can be any store such as Excel or a text file? Thank you.

  Start passing by examples of LabVIEW.  Go to help-> find examples.  There are several examples here just for the analog input and then even more for logging data to a file.  After that, show us what you have and we can guide you a little better that way.

• Compact DAQ data acquisition

  Hello

  I'm working on the proposed acquisition of data using data Compact - 9178 OR, in the I module in the series C NI 9213, NI 9205, NI 9207 (Thermocouple, current & and voltage units of measurement respectively).

  I created tasks using these tasks and MAX to read the data in my LabVIEW VI. [I use read AI VI only]

  The task of settings, mode of acquisition - N examples, examples of read-2, Rate (Hz) - 100 m

  the above parameters is the same for all three cards.

  When I try to read 1 data device tell data from NI 9207 - I can read 200 samples per minute. When I try to read data from all 3 units I see no delay,

  Basically, complete 1 iteration of acquisition, to 1.4 to 1.5 seconds.

  Is there a better way to increase the speed of acquisition?

  Thank you

  My bad. A confused with frequency conversion. All good now. Sorry

  Looking for 10 samples every 100ms, and I had programmed 10 samples every 2 seconds

• Several timers loop data acquisition

  Hi all

  I am developing a VI for FPGA Deployment. My equipment consists of a chassis/controller for cRIO-9072 with module 1-9211 thermocouple, card SD-1 module, 3-9215 HAVE modules and universal modules 2-9219. I will collect data of two thermocouples on the 9211, 14 channels on 9215 channels and 6 on 9219 modules. This system communicates to the host via ethernet.

  I have prepared a vi (see attachment), which used two DMA FIFO for writing data to data acquisition at a different speed. I will be sampling the s and 9211 9219 much more slow (500ms by samples), than other channels (40 ch/kech. / s). Currently, my FPGA vi trying only to taste two different modules. When I run the present on the host vi and try to read the data, I get only extracts of the data at different intervals. If either of her would reveal latency with the connection or the host vi failed to refresh quite quickly? I am relatively new to labview, so any help is appreciated. Thank you.

  Gaussy

  Hi Guassy,

  There are a few things that you need to change:

  (1) you must separate your acquisition in the FPGA in two separate loops if they have to operate at different speeds.  As it is, probably will run at the slower speed of the two parameters.

  (2) you must do the same in your VI in real time, or set up the DMA readings so that they will be read at the same pace.  For example, suppose that a single module acquires 1000 hz and the other at 200 hz.  If you want to read 100 samples from the first module (so your reading will occur at 1000 hz / 100 samples = 10 hz), you will need to read 20 samples from the slower module, so it is synchronized with the first module.

  (3) your timeouts are too short on your DMA readings.  Your slow acquisition is 500 us.  It will take 50 ms to read 100 samples requested, but the delay is set for 10 ms, so 4 times over 5 playback will return nothing.

  (4) you use graphics and no graphics.  A chart will only show the current data buffer that was written for her.  Refresh rate of the façade is nondeterministic, so that you can't see every update.  If you use a chart, the chart will record all data written on it to the indicated depth (default is 1024 elements).

  Also remember that you can have three FIFOs DMA between the host and the target FPGA, so use them wisely.  It is often easier to perform your purchases on the FPGA at the same pace and send them through the DMA FIFO even in VI in real-time.  If you need a few channels to connect at a lower rate, you can always throw the excess samples (there are some decimate wave screws that are perfect for this).

  I hope that helps!

• LabVIEW data acquisition Setup Multifunction DAQ

  I have doubts as to the acquisition of data in the LabView environment. I used the block diagram (Figure 1) below to review the update of the readings for the execution of a loop.

  Block 1 has been used to enable a task (first steps) with 3 channels (al) analog input AI3 and even set up the channel. In this case, the data bus (data-block 4) are construindos by 4 columns of data (provided by task 3 AI3 more).

  Block 2 is used to set the sampling rate in this case is 1 Hz (1 sample per channel x 1 rate).

  In this case, it worked as I expected (Figure 2). This allows to conclude that the interval between each sample was 1 second. The saw took a second in the iteration.

  The second step was to change the amount of data sampled in accordance with Figure 3 channels in block 3.

  Now, each channel showed 10 samples, while there are 4 channels configured, we have 40 samples. In this case the iteration totalled 10seconds (point to 1 Hz and 10 samples per channel-figure 4).

  The first question is what is the time between each sample obtained by channel?

  In this type of configuration (multiple channels), block 3 provides 10 samples in each channel, as well as the sampling is done, IE, the block gets 3 10 samples from a channel and passes to the next channel or gets 1 comp each channel and repeat this process up to 10 samples per channel?

  What is the best way to make sure that the interval between each sample is constant?

  If anyone knows any text that explains what the function blocks of data acquisition information please.

  Thank you

  Gabriel

  Well, there are several ways to read the signals of multiple signals, and each of them has different behavior. I couldn't see how you get mutiple channels, because in the two codes, you set a channel in your codes. Take a look at this figure:

  

  Here you can see how to set multiple channels using DAQmx, using commas to separate the channels. About the ways different ways that you can read the signals, you can look at the links I sent in my first post to learn more about them.

  In a few words, the time between samples from the same channel is T = 1/Fs, corresponding to the sampling frequency Fs. It is not a rule to determine the interval between samples from different channels, because it will depend on how you did your code, and as I sad, there are different ways to do. You can acquire the samples at the same time, or you can configure your code to read a fixed number of points of a channel and then read another fixed number of samples to another channel (https://decibel.ni.com/content/docs/DOC-28279). You can acquire a finite number of points, or you can acquire all the time. Yet once, take a look at the material that I have already sent. It will help you find the best solution to achieve your code according to your application.

  Kind regards

  Pedro

• USB multi channel data acquisition

  I use the VI to arduino HC-06 bluettoth of data acquisition. I would like to acquire data multicahnnel

  Could you suggest me how to acquire multichannel data from USB? To do this, how I have to program the arduino?

  The crux of your property doesn't do anything since you not write anything.

  Why you set the number of bytes to read at 8? You send more than that. You should be able to set it to a high number, such as 1000. Why do you use a dbl for this control?

• How to increase the speed of data acquisition?

  Hey, currently I using 6210 OR of data acquisition and control switch. I used labview to periodically check the 7 switches and read data from 7 channels in the meantime (1 sample on request). I ran 70 loops for 10 groups of data, the cost of the time looked like 2.2 seconds.

  I would like to end a 700 loops in 2 seconds, is it possible to improve?

  Thank you

  PEM

  Look at the Terminal stop of the DAQ Assistant Express VI. You are starting and stopping of the task for the acquisition of data on each iteration of the loop.

  Starting from the help file:

  Stop

  Specifies to stop the task and release device resources when this Express VI ends execution. For ongoing tasks, this entry is FALSE by default, which means that the task is running until the application terminates. To stop the task, you can use the device again in the same application, wire control wire you the Conditional stop this entry to the same terminal of the while loop. For single-point and finished tasks, this entry is TRUE by default, which means work stoppages after all samples are acquired. To optimize the performance of single point when using this Express VI into a loop, wire control wire you the Conditional stop this entry to the same terminal of the while loop.

  Also from the help file:

  Continuous single point of entry or exit, the of VI Express DAQ Assistant cannot allow optimal operation. See Acq & chart voltage-Single Point optimization VI in examples\DAQmx\Analog In\Measure Voltage.llb for an example of techniques to create more powerful applications, single point of I/O.

• How to find the time between two channels of entry in the data acquisition card or pci 6036

  Hello

  I read a lot-related posts on the simultaneous measurement of two input voltage of similar channels in map data acquisition. I know that the best material is "simultaneous measurments of the Series DAQ cards" but I only pci data acquisition card 6036 and I try to understand what is the time between the reading of the two channels . This period is always constant? (must it rely on a voltage (amplitude, frequency, waveform..). I send the sine wave (s) to the two channels and read the values of V, if they read the same value, the difference should always be zero but I get-0,002 to 0.002 Volt difference (I must find a way to convert it in time). A screenshot of my VI is attached. I wonder how I can accurately measure the time delay between the channel.

  I am open to any suggestion, my final goal to read exactly two channels at the same time ((ou connaître le délai exact donc je peux correspondre les données correspondantes étant donné le temps de retard))

  Hi spinup,

  better you should post your question in the forum of LabVIEW, LabWindows/CVI is used

  Good luck.

• Control and simulation and data acquisition

  Hello

  I am applying to motor control in Labview. I'm sampling speed from DC engine in real time through an acquisition of data. (my sampling time is 1000 samples per second)

  Then wrap speed as input to a Simulation (simulation and design of the order) and inside the loop simulation, I have a PID controller. The PID has the actual speed of the engine for the acquisition of data and the engine reference speed as input.

  Reference engine speed comes from the generator of signals (control design and simulation-Simulation) and is a waveform.

  My step in the engine size is 1000.

  I am running this application real-time and drawing the reference signal and the motor real signals. I run into several problems with regard to the calendar.

  1. when I change the size of the step of the simulation loop, the frequency of squares of reference also seems to change. For example. What step size = 1000, duration of pulse = 1 s. What step size = 100, pulse width = 0.1. (My pulse frequency is 1 Hz, Simulation clock - 10 kHz). How step size can affect the pulse width.

  2. can you explain the relationship between the DAQ, the Simulation step size loop sampling time, Loop Simulation period.

  3. If I want to collect different sets of data using sampling different hours, it's OK to change the sampling DAQ time without changing the size of the step of the simulation.

  Would also like to emphasize that the DAQmx calendar under sample clock mode is placed in front of the simulation loop and the output is connected to the loop simulation.

  Appreciate any help.

  Hello

  Maybe some screenshots of your code would help. Furthermore, what you have read your samples together with your DAQ screws?

  (1) If you have a waveform, the output is specified as:

  

  For example, if you change the size of the step of the simulation loop, you change the simulation time which are introduced into the signal generator and affecting the waveform that you see if you do not have a size quite small step to characterize the waveform that you generate.

  (2) sampling DAQ rate is the speed at which samples are taken on the acquisition of card data itself. The size of the simulation step, help. "Specifies the interval between the time when the ODE Solver evaluates the model and updates the results of the model, in a few seconds." Simulation loop, still using, "Indicates the amount of time that elapses between two subsequent iterations of the loop of control & Simulation.". " "Step size determine the value of t that is introduced to the functions you use in the loop simulation while the loop simulation period controls simply to how fast you change the following t value. The sampling rate of DAQ hardware is a clock of completely separate hardware controlling the analogue-digital on the DAQ card converter so that you can get a deterministic dt between the samples being acquired.

  (3) you can change the schedule for the acquisition of data, but you will need to restart each time the changes take effect. If you change the calendar of data acquisition and want your values to correlate with your simulation, you will need to change your size of step as well.

  -Zach

  -Zach

• Reading data with the USB-6216 CAN?

  Hi all

  I apologize in advance if this has been discussed before. Looking for a CAN isn't very productive because each instance of "can" is as follows. Controller Area Network is the name of long form, but it does not appear to have been mentioned on this forum.

  I have an USB data acquisition card - 6216 BNC. I am interested in reading the data CAN a MoTec data logger on it. National Instruments offers a series of white papers on the CAN, but they focus on their families of NI CAN hardware, as these USB units.

  Is there a reason why I can't run CAN given in my (USB - 6216 BNC) multifunction data acquisition? It's just digital data and I believe that the sampling frequency should be enough, especially since I can run my network at different speeds CAN. I'm almost tempted to try to build a program of reading of CAN using digital DAQmx tasks just to see if it would work. But I wanted to check with this Council first to see if there was something missing because no one seems to have tried this before.

  Kind regards

  Of course, they do not work. Any other hardware and drivers.

  Your card has avoiding only if you have no "sampling rate". The best you can expect is not more than 1 kHz, with a considerable jitter of the operating system. You see not all posts on the topic because people choose the right hardware for it. It really is a simple solution.

• How is data acquisition works in Labview

  
  

  Signal Express is a software from National Instruments project (evolved from the previous software as recorder of NOR) which offers basic data acquisition features: acquire signals, signals, filter, log file, displaying output.  LabVIEW is a programming language that allows you to do all these things, but much, much, much more.

  If you use a LabVIEW so you need not Signal Express.  You use DAQmx features in LabVIEW to acquire data of your DAQ hardware.  Start by reading http://www.ni.com/white-paper/5438/en.  Actually, there is a lot of information on DAQmx.  Look in LabVIEW in the Finder of the example.  Search ni.com DAQmx and filter on the tutorials.

• Real-time display at the high frequency of data acquisition with continuous recording

  Hi all

  I encountered a problem and you need help.

  I collect tensions and corresponding currents via a card PCI-6221. While acquiriing data, I would like to see the values on a XY graph, so that I can also check current vs only voltage/current / time. In addition, data should be recorded on the acquisition.

  First, I create hannels to analog input with the Virutal DAQmx channel create, then I set the sampling frequency and the mode and begin the tasks. The DAQmx.Read is placed in a while loop. Because of the high noise to signal, I want to average for example every 200 points of the current and acquired for this draw versus the average acquisition time or average voltage. The recording of the data should also appear in the while loop.

  The first thing, I thought, was to run in continuous Mode data acquisition and utilization for example 10 k s/s sampling frequency. The DAQmx.Read is set to 1 D Wfm N Chan N Samp (there are 4 channels in total) and the number of samples per channel for example is 1000 to avoid the errors/subscribe for more of the buffer. Each of these packages of 1000 samples should be separatet (I use Index Array at the moment). After gaining separate waveforms out of table 1 d of waveforms, I extracted the value of Y to get items of waveform. The error that results must then be treated to get average values.

  But how to get these averages without delaying my code?

  My idea/concern is this: I've read 1000 samples after about 0.1 s. These then are divded into single waveforms, time information are subtracted, a sort of loop to sprawl is used (I don't know how this exactly), the data are transferred to a XY Chart and saved to a .dat file. After all that's happened (I hope I understood correctly the flow of data within a while loop), the code in the while loop again then 1000 samples read and are processed.

  But if the treatment was too long the DAQmx.Read runs too late and cycle to cycle, reading buffer behind the generation of data on the card PCI-6221.

  This concern is reasonable? And how can I get around this? Does anyone know a way to average and save the data?

  I mean, the first thing that I would consider increasing the number of samples per channel, but this also increases the duration of the data processing.

  The other question is on the calendar. If I understand correctly, the timestamp is generated once when the task starts (with the DAQmxStartTask) and the time difference betweeen the datapoints is then computed by 1 divded by the sampling frequency. However, if the treatment takes considerable time, how can I make sure, that this error does not accumulate?

  I'm sorry for the long plain text!

  You can find my attached example-vi(only to show roughly what I was thinking, I know there are two averaging-functions and the rate are not correctly set now).

  Best wishes and thank you in advance,

  MR. KSE

  PS: I should add: imagine the acquisition of data running on a really old and slow PC, for example a Pentium III.

  PPS: I do not know why, but I can't reach my vi...

  
  

• Reading data Zumbach USYS

  I'm looking for a driver or a VI read data of diameter of a Zumbach USYS.

  We will acquire 5 or less reads per second for 5 hours.

  Has anyone interfaced with a Zumbach USYS?

  Is - what the Zumbach has a RS 232 port.

  Can I just put a sub 'read rs 232' vi in my loop to capture playback in diameter?

  Or should I create a RS 232 interface with the Zumbach driver?

  Thank you

  Bill

  I worked with a probe diameter Zumbach laser in the past, although not this model. The probe was a series very simple ASCII protocol which basically just sent two diameters that he measured in a single case. I think that the structure has been documented in the material, but if not, you can also just read data and see how it is structured.

  To answer your question - Yes, you would simply use a VISA to read data from the serial port.