I32 flipping index iteration continuous data acquisition

Similar Questions

• Excerpts from continuous data acquisition

  Hello

  I want to make an acquisition of continuous data with a NEITHER-6133 @ 1ms per channel. The data must be stored on hard disk. At the same time, I want to take excerpts from acquisition to calculate different values. The acquisition of the extract must be triggert by an external digital trigger.  Are there examples, which combine continuous data collection and collection excerpts?

  Thank you very much.

  Best regards

  Michael

  System

  Windows 7

  LabVIEW 2012

  NOR-6133

  Thanks to the support of NOR-Germany, I found a solution for me:

  1.) continuous trigger switch

  Connect 2) the trigger for the signal to a digital i/o

  3.) synchronize AI and DIO

  Excerpt 4.) the samples needed by the search within the digital waveform pattern

  Result:

  The example shows 4 IA channels Cup (tested on Win7, NI PCI-6115, 4 channels each 5. MECH / s) and calculation on extracts from each channel signal triggered parts.

  

• Continuous data acquisition and real-time analysis

  

  Hi all

  It is a VI for the continuous acquisition of an ECG signal. As far as I understand that the analog read DAQmx VI must be placed inside a while loop so it can acquire the data permanently, I need perform filtering and analysis of the wave in real time. How I implemented the block schema means that data stays int the while loop, and AFAIK the data will be transferred on through the tunnels of data once the loop ends the execution, it clearly isn't real-time data processing.

  The only way I can think to fixing this problem is by placing another loop that covers the screw scene filtering and using some sort of registeing shift to transmit the data in the second while loop. My question is whether or not it would introduce some sort of delay, and weather or not it would be supposed to be the treatment in real time. Wouldn't be better to place all the screws (aquicition and filtering) inside a while loop? or it is a bad programming practice. Other features I need to do is back up the data I na file, but only when the user wants to do.

  Any advice would be appreciated.

  You have two options:

  • A. as you said, you can place the code inside your current while loop to perform the treatment.  If you're smart, you won't need to put one another while loop inside your existing (nested loops).  But it totally depends on the type of treatment that you do.
  • B. create a second parallel loop to perform the treatment.  This would be separate processes to ensure that the treatment is not obstacle to your purchase.  For more information, see here .

  Your choice really depends on the transformation that you plan to perform.  If it's much the processor, this could introduce delays as you said.

  I would recommend that you start at any place in the first loop and see if your DAQ buffer overruns (you can monitor the rear of the buffer during operation).  If so, you should decouple the process in separate loops.

  In what concerns or not ' it would be considered as real time processing ' is a trick question.  Most of the people on these forums say that your system is NEVER in real time because you're using a desktop PC to perform processing (note: I guess it's the code that runs on a laptop or desktop?).  It is not a deterministic systemand your data is already "old" by the time wherever he leaves your DAQ buffer.  But the answer to your question really depends on how you define "real time processing".  Many lay it will set as the treatment of 'live' data... but what is "actual data"?

• Continuous data acquisition programming

  I wrote a program that I use to get the measurements continuously to a load with the DAQ assistant (attached) cell. I want to measure load values every 0.5 seconds and record each value using Scripture in the action file. I'm having some problems with getting the output file, I need. The parameters of the DAQ assistant are:

  -Continuous measurement

  -2 Hz sampling frequency

  samples - 1800

  - and a waiting period of 900 seconds

  I want to be able to hit stop them at any time and at the end of the program. However, what is happening is that the program continues to operate until the 900 seconds is over. Is it because I made it clear to get samples of 1800? If I leave it blank, it defines a number itself. I read somewhere that the definition of the value-1 allows an infinite number of samples, but that returned an error.

  Another question, I'll have, it's that if I allow the program to run after the timeout I put, it inserts a header after every sequence of timeout. I can't understand what is with wrong with my code, thanks for any help.

  Basic arithmetic. 1800 samples/2Samples/s = 900 seconds.

  Why accumulate so many samples at once? Reduce the number of samples at 2 and just wait 1 second for the Stop button to be recognized.

  If you don't want a header for each segment, then uncheck that in writing to the configuration of the action file.

• Moving average filter w / continuous data acquisition

  I'm looking to filter multiple signals of noisey. I am currently using a NI9203 w / a cDAQ-9174 sampling to 1000 Hz. I use DAQmx vi to start the task and acquire the signal. I tried using coefficients.vi smoothing filter combined with IIF filter.vi (Avg.png movement) it seems to work for simulated signals and recorded data. However, when I try to use this configuration for an average of real time it cut everything just all signals to zero.  I looked into the use of shift registers, but to get the necessary result, it seems that I have to use hundreds of items.

  In the end, I'm trying to filter the signal to get a constant more of reading for the user. For example during operation, the user needs to review the current state of the values in real time. It's currently difficult when the noise indicates the values of +/-100 changing every 100ms.

  For any help or suggestion would be appreciated, thanks in advance.

  Thank you all for the help and advice. I have attached the vi that I used to solve the problem, one of my major problems was not timing DAQmx using. Attaché in 2012 and 2013.

• 2-channel continuous data acquisition

  Hello

  I wonder how I could acquire signals of 2 channels at all times. I tried to find an example of vi but could not find one. In the vi below, I copied the same functions that work for a single channel, but it does not work.

  Best regards

  Ninjatovitch

  It should be Dev1 / ai0:1 as described above where ai0 is channel 0 and ai1 is channel one. They are separated by a ':' that specifies the range. Take a look at the following:

  What is the syntax for strings of physical channel in DAQmx?

• digital triggering of stop/start of analog data acquisition

  I want to use a signal from a digital line to start and stop analog data acquisition. The signal can change levels several times during a race of the VI so I have to start and stop several times data acquisition and store each session data in a different file.

  I tried to play with the following screw: digital triggering of break, DigitalStartandStopTrigger and ContAcq_DigTrig. None of them doesn't seem to work for my configuration. I also do continuous data acquisition so I can't use a reference. I use PCI 6259 DAQ.

  I used the "P0" pins rather than PFI pin on the grid BNC-2090. I know... stupid enough.

• 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...

  
  

• 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.

• data acquisition won't taste at the specified rate

  Material: C - DAQ 9178, AI 9239, inside a servo and an encoder potentiometer module

  Setup: I use the 9239 to measure the angular position of my servo and encoder of trees by streaming came pressure pot of the servo and my encoder. I put the sampling frequency on the DAQmx - Schedule VI to 100 Hz.

  Problem: I don't think that my DAQ is sampling data at 100 Hz because my VI registers more than 10 000 data points for a 10 second test. In addition, every time I have save my data in a text file, the vector of time my test data resets after a number of iterations.

  To debug, I tried the following configuration:

  I've defined the sampling frequency of 100 Hz (or is that s/s?), the samples per channel (size of buffer for continuous mode) at 2000 samples, number of samples per channel up to 10 and loop milliseconds timer on my VI at 10 m accordingly, data acquisition would send 100 samples per second (or 1 sample every 10 ms) on my PC buffer (which could store 20 X that amount). Then LabVIEW would read up to 10 samples per loop iteration (which is itself ~ 100 Hz) and work with these 10 samples inside the loop. However, since the loop is operating close to the sampling frequency of data acquisition, then LV should only work with 1 sample each iteration of the loop (100 Hz / 100 Hz)-not the 10-sample-max that I specified.

  However, I stumbled on "error-200279: the application is not able to cope with the acquisition of material" when I ran the program. Why?

  My code and materials should be easily able to cope with data acquisition - at least the way I put it in place

  This whole situation wondered my fundamental understanding of data acquisition timing, so I would really appreciate an explanation of exactly how to deliver DAQmx uses data synchronization, why my DAQ sample at 100 Hz, and how can I fix the calendar specified by the user.

  Thank you!

  aeroAggie wrote:

  The C - DAQ 9178 there some minimum sampling rate I will not meet?

  It's actually the 9239 that limit your sampling rate.  Read the data sheeton page 5 there's available data rates.  In short, your data rate allowed is 50kS/s / n, where is goes from 1 to 31.  50 k/31 gives you 1.6kS / s.  So, it's the minimum sampling frequency that can be used.

• 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 .vi DAQmx Read (analog 2D NChan DBL NSamp) to acquire continuous data?

  I try to get the .vi DAQmx Read (analog 2D NChan DBL NSamp) to acquire data continuously.  The 'help' indicates I need to wire the number of samples per channel-1, but it doesn't seem to work for my application.  If I have the wiring to any number greater than 0, the data collection works, but is not continuous.  I enclose the code (Sept15_MainPanel_WorkingBaselines_ApplyBaselines and Calibration.vi) and a Subvi (Collect_Baselines.vi) if someone wants to take a look.

  Here's what I'm trying to do:

  I use a unit NI USB-6009 to collect analog voltages of load cells 2 (channel 0 and channel 1) and 2 displacement transducers (channel 2 and 3).  The main panel of the VI contains a listbox with 4 options - 'Check EMG channel', "Collect base lines," "Collect Data" and "end of program".  'Collect base lines' 'End of program' work and I'm working on writing code to "Collect data".

  For the option "Basic collection", 2500 samples are read from 4 channels described above and 2500 samples are averaged.  This works.

  The option "Data collection" - I would like to that data from 4 channels to acquire permanently.  Finally, for the option of data collection, data acquisition stops when channel 0 detects the force of 200 N - so I will not always have a finite number of samples read.  The time it takes to reach the value of this force will be different for each test.

  -How can I get continuous samples for my 4 channel?  Is .vi DAQmx Read (analog 2D NChan DBL NSamp) function badly and if yes, what should I use?

  Thanks in advance for any ideas or advice.

  Esther

  First, in case 1, you need not the structure of flat sequence.  The son of the error and data properly will dictate the flow of execution.  Then, in State 2, you must initialize the shift register, unless you want to keep the data is accumulated each time that you run the vi.  The reason why you don't see all the data here is because you have - 1 wired for the number of samples per input channel.  You must connect a number here, even if you are taking continuous samples.  The service needs to know how much sample to gather at one time.  If you put-1 here, the number of samples per channel must be set up in the synchronization function DAQmx (sample clock).  If you specify a number here, then you put-1 in playback function.  The DAQ hardware will read continuously, you must retrieve the data from time to time, so you must specify the number of samples.  By reading inside a loop, it will continue to read until the stop function is encountered.  I guess that the Clear function acts as a stop.  But you must always indicate playback vi how many samples to read and return on each iteration of the loop.

  The documentation is a little misleading.  He warns that a - 1 will cause a continuous reading.  But the pads are so big, he can not read continuously forever without losing data.  If you specify a finite number, playback in a loop, and he will read this number and return the data (empty the internal buffer) at each iteration of the loop.  Continuous means that you just call the start function once.  He will read at each iteration of the loop until the stop function (or clear) is called.

  Here is the difference between the setting of the Timing DAQmx function for continuous or finished reading: finite samples requires a tenure, he reads the finite number of samples, and it's done.  It requires another start to read more data.  Continues to read requires only a start.  It still reads a finite number of samples, but when this is done, you can retrieve the data by calling the read function until he could continue.  After the reading, you don't have to call for new start.  Look at it this way.  Start is what starts the collection of data, not the read function.  Just read empty buffers in your data feed.  The data acquisition continues in continuous mode, but you must call read again to get the data on the pads.  If you specify basically buffer size when you set the number of samples per channel.

• 2 channels of AI on a data acquisition with the range of different sensitivity

  This vi is based on the 'new project' state machine on the home screen at the start of LV.

  A time loop is parallel to the main loop of the state machine, shown in the picture.

  It works continuously until you press the Exit button.

  The problem seems to be in start this... > read >... stop start > read >... stop along the error line.

  The reason for this clumsy arrangement power is measured voltages are in two lines of different sensitivity.

  The shunt voltage is small and needs-. 2 to the range of V.2. The load voltage is greater and 09:50 V range is good.

  In the initializing state, two separate vi 'create a channel' have been used to specify the range of voltage to the physical channel. The corresponding tasks are sent via via local variables.

  DAQmx errors happen randomly, sometimes the first iteration, sometimes the 50th.

  I tried to disable one or the other start > read > stop for the shunt voltage or load.

  I tried replacing them with the DAQ assistant.

  I tried various DAQmx vi: "wait" and "accomplishment of the tasks by resource cancel selected".

  But error-50103 "specify resource is reserved" keeps popping up.

  Is it possible to create two tasks on the device even when they are not used at the same time?

  The only reason is to measure in two voltage ranges.

  Win 7 Pro 64-bit

  2014 LV database

  Data acquisition equipment: USB-6210

  Thank you.

  This has been discussed many times. Do NOT use separate tasks. You can use different ranges for different channels with a single task. Just wire the task from one channel to another channel to create task.

  You also use local variables when they are certainly not needed.

• Code error-200279 for data acquisition

  Hi all

  I am trying to build a small program of data acquisition, but I get a 200279 error telling me to increase the buffertime. What I am doing wrong?

  

  Andersson wrote:

  No, you're right. I don't get the error, I turn off highlight execution.

  It seems so. I did not understand why he would come with an error during the audit of the code with the bulb. It seems like what I discovered on www.ni, one can avoid the error of initialization of certain data for the chart.

  Not sure if I got it 100% correct however. Here is the link:

  http://digital.NI.com/public.nsf/allkb/A647A1BE3DA8336786257AAA0066B45B

  I don't have any other loop in the installer. I'm sorry for the confusion with the name 'producer loop. It's the only loop in the code, I deleted the rest to refine the error.

  Is the conclusion that the program is good? Or do I have to do something to remove the error?

  The table has nothing to do with your error.  It's strictly highlight execution.

  When you configure a continuous sampling, start the collection of data at a given flow rate.  It is so big a configuration of the buffer.  There is an article that tells how much room it is exactly, but for the sake of argument, let's say 10 seconds worth of data.  In normal execution, your code runs pretty quickly that she is able to empty the buffer as soon as the data are acquired.  But when you enable execution of climax, your VI slows down to a crawl so that he can show that you step by step what is happening on each wire.  Your data acquisition always occurs in the background.  Execution of idle is to take much longer that data are acquired.  Within one or more loop iterations, you have filled the buffer and get the error message.

  You cannot use point culminating performance when you use a device of data acquisition in this way (or VISA ports either) where data are sent continuously at a speed that is independent of speed, the code is executed.

• Why data acquisition in an executable collect fewer samples?

  Hello

  I have LV2012 on Windows and SMU-6341 map in PXI chassis.

  I have a task for the acquisition of data on I-1 on my monstrous application. Well, to get to the point, I have here a case where the task of data acquisition starts, waiting 20ms, reads all available samples and puts an end to the task. For the parameters see the piece attached. Then, the collected data is plotted on a waveform graph. Usually about 200 samples are taken in the case of data acquisition. Then loops shown sequence, until certain conditions are met.

  Unfortunately a problem occurs when I deploy a rack application (exe) on a production PC some 600 miles away from me.

  This is an example of what I get on my development PC (LV and runtime give similar results):

  

  This is an example of what I get on the production of exe PC (13 iterations, bad luck ):

  

  It totally looks like the data acquisition task mentioned seizes one sample to an iteration of the loop.

  I enclose a noodle dragged out of the main program. I'm about to test the version of this noodle on the production of PC in a few hours, but I would like to hear all the ideas that emerge.

  Thanks in advance!

  cubz wrote: from my experience, the continuous 'Samples' mode does not stop when the buffer is full. The loop of 4 seconds (with 10 k samples/s in the sample buffer 40 k)-that is to say samples how finished works IMO.

  If the buffer is filled in continuous mode of the samples, you will get an error.  I'm sure it's something you don't want.  In this example, you have provided, you really should have finished samples and has said the acquisition of data to read samples of N.  It is the only way to ensure you get all the data you want.

  In regards to your differences between development and executable, the executable file tends to only not nearly as happening (Debug stuff for the most part), so it tends to run faster.  If you're depending on a software clock, anything can happen (having a ton of little or no data).  That is why we say you use the clock machine and get the number of samples that you actually want.