USB multi channel data acquisition

Similar Questions

• multi channels data acquisition, a single frequency, counter a pulse, two voltage inputs, a power meter (by USB) and an analog output spontaneous and recording

  Hello

  I have a power meter which provide the USB driver and a Labview program to get the data and NI USB-6221. The project I am currently working on the needs of:

  1 acquire two signals (inputs of simple tension), pressure frequency KHz

  2. acquire a flow signal, the output signal is 0 to 5V pulse, each pulse means 0.4 ml volume. So I use a voltage inflows to count impulses in certain period of time (in this case, 1 S) for water flow. ; KHz sampling frequency and the 1 Hz update rate

  3. acquire a signal of engine speed. The output signal is pulse square wave whose frequency is related to the speed. I use a REIT port to measure the frequency. Sampling rate: Auto

  4 give output voltage sine or square wave, I use AO do that.output rate: Auto

  5 acquiring by VISA electricity meter data.  Data update rate: every 50ms

  Currently, all the 5 tasks work well separately. But when I put them together, some signals are beginning to hang, for example, pressure signals sometimes give nothing.

  Another problem is the data record. I programmed the VI in such a way that whenever I press the button 'save start', he begins to record data and save them in a .cvs file. For some reason, I always get only the data in the first table. Coult someone help me? I download my code as follows

  Hello

  What I meant by open, write, close.  For any type of file you are using.

  Open the file, which produces a reference, then put the mention in a registry to offset.

  Write data, using the function write (for this type of file) and the reference.

  When you are finished, close the file reference.

  Writing in the spreadsheet opens, written, close all at once.  It is very good for this type of application.

  ***

  The issue of the loop is more general.  I would like to say first of all, I want to say that since each loop works on its own, it is own VI, and that this program has put all this into a single VI, which has a method to solve the problem is to disable all the loops and allow them one at a time to see if there is a culprit responsible for.

  Using multiple loops executes the code at the same time, and some loops would be cycle faster than others, especially if some of them are loops just as they are.

  Communication between the loops is a test to the address if necessary.

  Running all these signals through different loops DAQ must also be examined.  Don't know what questions are for read and write somewhat randomly in the channels.

• the 1900 myRIO FPGA multi channel data acquisition

  Hello world

  I would ask you for help in my program acquisition and generation of data. The main task of this program is to measure 4-channel adjustable sampling rate (2 kHz and less) and to generate an analogue signal in up to 50 kHz sampling frequency.

  I created two loops and everyone is dedicated to different operation. The first loop is to measure data, or in writing to the DMA FIFO and the second loop is dedicated to the generation of signals. I adjust the main parametrs of the two loops in a host of vi.

  But what is my problem. I compile the program in the FPGA of myRIO without any problems and I can run too but the problem is that sometimes, especially when I adjust the lower sampling frequency of the loop to measure to the rank of channel changes measured and I see that the signal that is connected to osciloskop AI0 channel on channel AI3. When I stop the program, set the higger sampling frequency and run it again, it works well and the signal is on the right channel. Could someone help me with this problem? I tried to check all the forums that I know, but I did find an article or a discussion of a similar problem.

  Thanks a lot... :-)

  Andrew,

  I just solved the problem. I thought about it again and I got the idea to change the size of the DMA buffer on the side of myRIO. I expanded the buffer of 1023 elements in 2047 and it works well and I can change the sampling without problems.

• DAQmx data acquisition with persistent error of nyquist

  Hi, I created a multi channel data acquisition vi (accelerometer 2 and 1 sound pressure) using models for producer.   The vi is attached. Thanks to labview 2011.  I get the error of nyquist (2 enclosed) when you make a bandpass filter between 50 to 5000Hz.  This happens despite having put my sampling rate to 22050Hz.  When I checked the output of wave I noticed that the signal has a dt 1 s.  The text output to check the result.  I could not understand how this is so since I had set the sample rate to 22 k Hz.  Any help will be much appreciated.  Thank you.

  I would do something like that.  You must calculate the dt of the set (with the recipricol) sampling frequency and use to initialize the shift registers.  This way you only need to change 1 constant if you need to change your sample rate.

  

• measure the angular speed, angle and trigger using a gyroscopic sensor breakout board and LabView data acquisition

  How to measure the angular velocity, the angle and trigger using a gyroscopic sensor breakout board and LabView data acquisition?

  There is a single channel data acquisition code which measures the angular velocity, angle and flexibility using a gyroscopic sensor breakout board and acquisition of LabView data attached to this, I need a help to creat two-channel data acquisition code?

  Hello

  Attached is a vi that you can use in order to read the measured angular position of an encoder.

  If you need more examples on the tasks that you can develop with NOR-DAQmx and LabVIEW, you just need to open LabVIEW and click Help > find examples > Input and Output material > DAQmx > entry counter.

  Kind regards

• Multi-channel acquisition - simultaneous Acquisition of sampling 1 & 2-channel single sample in a task

  I am able to get a multichannel simultaneous sampling on my acquisition of data (USB-6363) without problem. But what I want to do is make multi-channel acquisition in a single task where sampling requirements are different for each channel. For example, I want I want to acquire a total of 1000 samples on 3 channels in a single task with DAQmx as follows the characteristics of sample:

  • AI0: Analog Wfm 1Chan NSamp (998 samples)
  • AI1 + ai2: 1 d analog NChan DBL 1Samp (1 + 1 sample/channel)

  I know I could do just a regular multiple sampling multi-channel acquisition through all three channels then average down from channels 1 + 2, but I don't have that several samples to spare. AI0 is a bandwidth hog in my application and consumes all the samples of data acquisition (2. MECH / s), but I can save a few samples to make analog measurements further (for example, temperature, pressure).

  Ai0 takes place also permanently so additional analog measures on ai1 + ai2 need to be included in the same task.

  I don't know how to go on this matter or if it is still possible. Any ideas or thoughts would be greatly appreciated.

  Currently I use a second DAQ to read these additional channels at a lower rate but I need to pass a single data acquisition.

  How should continuous ai0 really be?  You of course can enjoy on ai0, and one of the other entries at the same time, then there would be some gap in your data.  In addition, if you want to go to the full 2 MHz, you may sample ai1 ai2 twice in order to allow entry to set (the maximum specified multi-channel rate is only 1 MHz due to compaction of the constraints on the MUX I believe).

  DAQmx sort of you lets set something up like that, if you "cheat" it by configuring each sample as a single channel in your task (see an example similar here).  If your 998 + 1 + 1 (or 996 + 2 + 2) becomes a task of channel 1000 (takes a bit more memory, but should still be feasible).

  I would consider a 2nd DAQ card a better option if ai0 really needs to be continuous.  You can go with a (9174 or 9178) cDAQ chassis a 9223 (only 1 MHz if) for quick entry and your choice of module for the slower entries.  On the cDAQ chassis a module can run a separate task of AI from other modules (up to 3 tasks HAVE by chassis) at different speeds.

  Best regards

• Synchronous channel multiple acquisition USB-6259 (phase measure)

  Hello!

  I want to create a user-signal (1 k at 20 kHz) in SignalExpress, generate it with the case NOR USB - 6259 BNC and measure with the same device after that the signal has passed a DUT I need the answer for a fixed term.

  For the moment, I'm trying this: I connected the output via a Y-coax analog (length 1 meter) to TWO analog inputs.

  Because the input channels have been grouped with the add a channel button, the data acquisition should occur almost synchronous.

  However, sometimes the phase response is zero (cause as expected the two signals must be equal), but sometimes it "jumps" (especially when I am running the new project) and increases or decreases linearly on the frequency (so there is a time difference between two measured signals).

  I don't think that running is the problem here, because referring to the manual, it's about some µseconds and I have not yet change the range of voltage between input channels. Furthermore, the magnitude response is fine.

  I has not yet perform to synchronize the input channels with the output of the channels either, but first I would be recognizing a solution for the entry-entry-synchronization, (I don't mind if it is implemented in LabView).

  Thanks in anticipation, Daniel

  Hello Daniel,.

  the M-Systems Series DAQ using a switch to sample multiple channels. So you have to take the time to switch into account when

  you do measures such as phase shift of two signals.

  I took your project Express of Signal but also created a LabVIEW VI to double check, and you can see exactly the same lag between the two

  sampled signals. If you want to measure the true phase differences, you have to use a device of simultaneous sampling like S or DSA series devices (there are more a few others).

  concerning

  MArco Brauner NIG.

  

• 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.

• Imaging multi channels using the acquisition card OR

  We have a 1408 IMAQ being controlled by LabVIEW 8.0.

  We want to install multi-channel of imagery. All the channels work individually. However, when I was trying to show two channels simultaneously, single channel works and I got the following error message:

  Error 1074397150 has occurred to IMAQ enter Setup.vi

  Possible reasons:

  NOR-IMAQ: A timeout error occurred while you wait for the specified event. If you expect a picture, make sure all the video data is acquired during the period. If you wait for a signal, check that the assertion of signal occurs within the period.

  Sometimes I get a different error message asking me to assign different buffers to both channels. I understand that IMAQ 1408 has only analog digital (ADC) converter to digitize the incoming video. It may acquire up to four different cameras, but only of a camera at a time.

  I don't mind do frame rate in half. I think to show only one channel at a time and do the two channels alternantly. But I need to know how config routes to get there.

  I've attached an example that should work.  I could not test it because I don't have the equipment, so it might need some settings.  I would test it with one channel by setting the channel # 1.  Once it works, define channels # 2.  I set the display to use snapshot mode so the same image can be used for all screens.

  The only reason that I can think of that would make multi-channel acquisition fail when single channel works is the lack of synchronization between signals.  The start of frame signal must be the same for all channels.

  Bruce

• 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.

• 6361 versatile usb data acquisition does not automatically detect the SCXI chassis/accessories

  versatile usb data acquisition 6361 will detect automatically SCXI chassis and accessories?

  Hello kdCMC,

  As far as I know that the SCXI-1600 USB Module is able to auto-detect SCXI Modules.
  This is also mentioned on page 11 and 12 of the following SCXI to start document:
  http://www.NI.com/PDF/manuals/373236m.PDF

  All data (including USB-variants such as the NI USB-6361) have only a 68 pin shielded cable (IO) between the DAQ hardware and the SCXI chassis.
  This cable does not auto-detect opportunities since it basically just "transfers analog and digital signals" between SCXI chassis and DAQ hardware.

  Is there a specific document that created the confusion on this subject?

• USB 6008 data acquisition: automatically turning in a port

  Hi all someone could please help me.

  I need to autoamtically send output didgital since my data acquisition based on a value. the bottom of my little project. I read in a database if a value is equal to a certain value, I want to send a digital camera of the signal of acquiring data in a relay, so for example if the value 1 database generates a digital signl 0 7 port line.

  If someone could help it would be much appreciated

  So what's the problem with sending AUTOMATICALLY one. You simply compare the value of the database. A comparison function returns a true or false, which is quite ideal to display a true/false signal.

  Fix the code you wrote. This is not a service of howework and see some code real goes a long way to get detailed help.

• Configuration of the two of the same model data acquisition

  Hello, community of NOR.

  I'm an intern in mechanical engineering with experience in base with LabVIEW.

  I would like to speak to OR directly on this issue, but I don't have a service contract and my company wants me to understand this before you buy LabVIEW.

  I hope that someone has experience about my question, and I would be very happy to help.

  We intend on purchasing an expansion card for our acquisition of data (OMB-USB-2416), but unfortunately it is offline and no custom would not happen in time.

  So, I need LabVIEW to read voltage HAVE two of the same model of data acquisition, which would amount to about 30 channels.

  Is this possible with LabVIEW?

  Thank you.

  Measurement computing says that the "physical channels" dropdown list is automatically filled in once both devices are configured.

• How to get to multiple data acquisition voltage signals

  Hi guys,.

  I have to run an event for children to play with different types of energy production, so we have a wind turbine, solar panel and a generator. I have all of them connected to the ports of entry of the C USB DAQ series, I can't seem to find a way to make data acquisition out all three voltages simultaneously, the DAQ assistant in labview won't do it, AFAIK. I need all the outputs of all so that the children can see the reknewables plus and then complete the lack to win with the "power station" generator, so I need them all running at the same time. I had a quick glance at similar problems, but I don't see how they are relatable to my case.

  I have attached the vi below, thanks for your help.

  Amy

  DAQ Assistant allows multiple entries of tension. When the analog channel selection hold down the SHIFT key and then select as many channels available, you want.

• can I use instead of conditioning of analogue output signals data acquisition to provide voltage outputs analog?

  Hello guys,.

  I have a general question regarding the units of packaging such as the USB-9263 analog output signal. If I can use it instead of data acquisition to provide an analog voltage output?

  Thank you

  ELA

  Yes, the 9263 can provide 4 output channels analog voltage (+/-10 v range) with up to 1mA of current drive. Looks like: it refers to the short circuit of conditioning of signals and some protection against overvoltage. Link below is the User Guide:

  http://www.NI.com/PDF/manuals/372406b.PDF

  -AK2DM