start/stop data acquisition

Similar Questions

• How to stop the acquisition with a relaxation with the NI PCIe-6323

  Hi all

  I wonder if it is possible to stop data acquisition or pcie-6323 with a trigger pulse the same way that I begin to acquire samples with a finished sample mode trigger pulse.

  Thanks in advance

  M.

  The samplesPerChannel that you can show what the sample clock configuration defines the total number of samples for the acquisition of finishes.  In your case, you will read the data previously triggered so permanently in force this setting really only sets the size of the buffer.  If you want to just be large enough to avoid overtaking (although...) If the window you buy is potentially very short, you might want to explicitly configure the size of the buffer to something bigger and maintain the value of samplesPerChannel down so that the reference trigger can be accepted earlier).

  The numberOfSamples you specify when you start the player defines the number of samples for the next call for reading.  If you can read the small windows of streaming data to avoid having a blocking with a large timeout call.  If you do not want to change the time-out period, it is a property of the DAQStream class.

  The "continuous" examples (e.g. this one) should show how you can read back data asynchronous as it is acquired.  Your configuration looks more like a "continuous" example

  Since you want to start and stop using the same line as the trigger, perhaps an alternative to the evolution of the default read pointer would be to set up a central task of analog input with a relaxing break.  The caveat to this is that the break does not stop at the task and as soon as the line goes back to you will begin to acquire the data again - I would say using a meter to separate groups of samples in the buffer zone continued.  If you wish to purchase multiple windows of data in short succession well, then I would go with that instead to avoid having to restart the task (and potentially Miss samples during the restart of the task).

  Best regards

• choice of the model of design for data acquisition system

  Hi all

  I have a problem on the selection of the model design / architecture for a data acquisition system.

  Here are the details of the desired system:

  There are data acquisition hardware and I need to use by looking at the settings on the user interface.

  the period of data acquisition, channel list to analyze must be selected on the user interface. In addition, there are many interactions with the user interface. for example if the user selects a channel to add scanlist, I need to activate and make it visible to others on the user interface.

  When the user completes the channel selection, then he will press the button to start the data acquisition. Then, I also need to show the values scanned on a graph in real time and save them in a txt file.

  I know that I can not use producer consumer model here. because the data acquisition loop should wait for the settings to scan channels. and it works on a given period by the user. If the loop of user interface makes higher then loop (loop data acquisition) of consumption. This means that queue will be bigger, larger. If I use notifier this will be some data loss comes from the user interface.

  y at - it an idea about it? is there any model of design suitable for this case?

  Thanks in advance

  Best regards

  Veli BAYAR

  Software for embedded systems and hardware engineer

  Veli,

  I recommend the model producer/consumer with some modifications.

  You might need three loops.  I can't tell for sure from your brief description.

  The loop of the User Interface responds to the user for configuration entries and start/stop of acquisition.  The parameters and commands are passed to the Data Acquisition loop via a queue. In this loop is a machine States that slowed, Configuration, Acquisition and stop States (and perhaps others). The data is sent to the processing loop through another line. The processing loop performs any data processing, displays the data from the user, and records to file. A registrant can be used to send the Stop command or stop the loop of the UI for other loops.  If the amount of treatment is minimal and the time of writing files are not too long, the functions of processing loop might be able to happen in the case of the UI loop timeout structure of the event.  This makes things a little easier, but is not as flexible when changes need to be made.

  I'm not sure that there is a type of design for this exact configuration, but it is essentially a combination of the models Design of producer/consumer (data) and producer/consumer (events).

  Lynn

• How to run a window of data acquisition and another pane at the same time

  Hello

  I have a main window for data acquisition and in front panel there are four Sub Vi. When the main window of data acquisition is running and at the same time if I run the Subvi - main window stops data acquisition and the secondary window starts to run. But I want to launch the window of acquisition of primary data and the pane at the same time. Please give me a solution for this...

  Thanking in advance.

  Nikhil

  Hi Nikhil,

  My explanation has answered your question. Take a look at the image as an attachment. Let us know if you have any other questions.

• Is it possible to change the name of data acquisition device?

  Hi all

  Is it possible to change the name of device of data acquisition in a pragmatic way?

  I wish I had at the beginning, when I start the data acquisition control a name that my .net program assigns to the DAQ card. Is this possible?

  Thank you

  Virginia

  Ashly thanks!

  Virginia

• 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.

• data acquisition stops automatically

  I want to stop assistant DAQ automatically after a period of time, so I created this VI.

  When I start the program, it work and after reaching the value of time specific 50, the graphical indicator ' looks like "stop, but wait after 9999 second, the graphical indicator suddenly see a lot of data that seems to be taken for the 9999 seconds, what is happening? After that, it gives an error saying:

  Possible reasons:

  Attempted to read samples that are no longer available. The requested sample was already available, but has since been replaced.

  Increase in the size of buffer, most frequently the reading of data or by specifying a fixed number of samples to read instead of reading all available samples would correct the problem.

  Property: RelativeTo
  Corresponding value: current playback Position
  Property: Offset
  Corresponding value: 0

  Task name: _unnamedTask<100>

   

   

  Data acquisition cannot be stopped like that?

   

  Thank you

  Not quite.  Like this.

  

• Acquisition of data stops at data acquisition

  Hello

  See the attached VI.  Data acquisition acquires data without problem for a few minutes, and then suddenly the event structure does nothing but the timeout.  I'm deliberately ignore the 200279 error that is generated when two triggers are too close to each other, because I want to just ignore these triggers, but perhaps which also prevents tasks at a certain time?  I also tried to start and stop the task again in the case of timeout events, but it does not help (it causes an error).  Is there a way to prevent either the DAQ card (I use the box USB-6251) of the judgment of the data collection or a better way to ignore triggers that are too close together?

  I hope that I am making some sense here :-)

  Thank you

  Jeremy

  Jeremy,

  Thanks for letting me know about the 99% CPU usage.  It is definitely the cause of your accident and can be avoided by putting a funtion waiting with maybe 10 milliseconds in your timing loop.  However, if you want to keep avoiding strict with no node blocking, you will need to restructure your VI to use the Express VI of time elapsed since the range of Timing.  You will find examples of the use of this VI in detailed at the bottom help.

  Hope this helps, have a great weekend!

• I want cRIO to start and stop the acquisition by push physical button on the cRIO, is this possible?

  When you use my cRIO 9024 on the ground, I prefer to be able to start and stop the acquisition with pressing a physical button on cRIO.

  I want to say I don't want it to be "as a start-up," I don't want cRIO to start the acquisition as soon as the power supply is ensured.

  Is this possible?

  Hi Cashany,

  you will surely find this switch status. But there are easier ways (but more expensive) for a button. Fiddling with a pen or a small screwdriver to switch USER1 is not what I call "user friendly"...

  -You have at least 2 voltage inputs on your module available. Use a switch voltage on the power inputs. Use a 'real' button!

  -You have an available serial port. You can set some pins on GND or voltage and check their status inside the cRIO/RT target...

• VMware vCenter Server service stops or restarts at the start of data collection

  VMware vCenter Server service stops or restarts at the start of data collection

  I am using vCenter Server 5.0

  Whenever I have begin to collect data, vcenter service stops or restarts, if I stop data collection and to disable the agent, vcenter service again and works well.

  Please any help!

  Thanks in advance

  It is a known issue, relating to the collection of historical data being enabled (nonzero) in the properties of the VMWare Agent on the Agent status screen.

  Change to 0 to disable/re-enable the agent and it should fix the problem.

  Please open a ticket of level 1 with telephone support if you need more help.

• 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.

• 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.

• How to stop an acquisition continues in producer/consumer

  Hello

  I'm trying to use producer/consumer to control 'Start' and 'Stop' to my continuous data acquisition system. I can start the acquisition process successfully, but I can't stop it botton 'Stop '.

  I enclose my simplified VI. Can anyone help to have a look and tell me what is the problem here?

  Thank you

  Bing

  As I said before, use a notification utility and manage the expiration time.  I used a select statement with timeout? Optional Boolean.  If a time-out of events, use the previous value.  If we got a notification, use this value.

  

• 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.

• not able to write the data through data acquisition

  Hello

  In fact, I need to send a code word (text file) from the program matlab through my data acquisition (OR-USB-6215). my program (transmitter.vi [case structure: page2]) attached below has a problem to do the task. whenever I run the program it gives me an error like

  Error-200479 occurred at DAQmx start Task.vi:2

  Possible reasons:

  Measurements: Specified Operation cannot be performed during execution of the task.

  Task name: _unnamedTask<84>

  At the moment I don't see output in my oscilloscope. But, if I highlight my performance I observe my samples on the oscilloscope with the following error message

  200288 error has occurred in the DAQmx write (analog 1-d 1Chan NSamp DBL) .vi:3
  Possible reasons:

  Measurements: Attempted to write a sample beyond the final sample generated. The build is stopped, so the sample specified by the combination of the position and the offset is never available.

  Hi Raja,

  What I did is I moved the 'write DAQmx' outside the while loop. That made the VI in this case is read the file and passing it to a table, and then this table is formatted a waveform to be written to the data acquisition device.

  With respect to the way in which the data is read, I don't change anything, it was based on your original code. A good way to know if you write the correct data is to check the chart view in VI.

  So the question is, is the graphic display showing the good waveform?

  Best regards

  Faris