Producer/consumer or master/slave, acquisition, control, analysis and recording of data

Hi all

I have NEITHER cDaq-9188 and its modules NI 9214 (thermocouple), NI 9203 (HAVE current) and NI 9263 (AO tension). I need to measure the temperature and pressure, and according to these data, I need a frequency converter to drive a compressor control. I've developed acquisition, analysis and recording program by the use of the state machine, the design of producer/consumer model and I have no doubt about their. They all work very well. Now, I need to add a control program in their. The problem is that I need to check the compressor with feedback from temperature data permanently, but I do not necessarily all the data acquired and permanently from the results of the analyses. For example, I need to record data once in 30 seconds. Which model desing should I use for this task?

Edit: I was not able to find examples of advanced program relevant to the design of master-slave model. If you know where to find them, could you write in this thread please?


The declarant buffer not data.  Do only the queues.  A new notification replaces the old value if she is ever read or not.  You would be loss of data with the notifiers if the loop of consumers with a notification utility cannot keep up with the data that they fade.

What I show all the data buffers through the queue in the loop of the producer.  The queue of the consumer removes all data and do stuff with him (such as logging) if the elapsed time is over.  What is the problem with that? That is what for (imstuck) described in his message.

The other alternative is that you put the timer into the loop of the producer.  Have the Boolean value TimehasElapsed drive a deal structure this place only the data if the time is over.  In this case, only some data gets queued, and consumer loop removes all data as it gets and it opens a session.

Tags: NI Software

Similar Questions

  • Producer/consumer vs Master/Slave of data loss

    Hello users of Labview,.

    I did experiment with vs p / M/S lately in the context of data aquistion. Many messages did appear (correct me if I'm wrong) that p/c is the correct architecture to if the data retention is desired, so that's what I tried to implement.

    In the loop of producer, I've included 3 Assistant DAQ VIs (2AO, 1 HAVE), which generates data actively and which is being queued. I have 3 other loops of consumers, two of which are consumer 1) written loops of 2) outputs TDMS data of a chart 3) no producer: structure of the event, monitors changes to the user interface.

    When I run data acquisition, the generated file are always half either acquire the half of the sample that I've specified regardless of the sampling rate. I also have a strange displayed graph (see image).


    If I replace with a master/slave architecture, this seems to solve the problem.

    So question is: anyone met with this kind of problems? Are there disadvantages to stick with M/S instead of p/c in terms of data loss?

    Thank you

    johnji wrote:

    I think I'm well done

    You are not.  Once an article is removed, he went.  Since you have three loops made of the same queue, each loop will get ~1/3 of the data.  If all the loops are to treat everything, then you want another line for each loop and meet the producer, write to each queue.  You can also use a user event.

  • Producer/consumer problem: several loops/queues


    Please refer to my previous post ... > for more on the subject. I was told to try a producer/consumer architecture, so I decided to go and do it.

    After doing much research, I come back to ask for help.  I decided to try to implement three loops. The reason for this is because I thought that the length of each loop synchronization can be controlled independently as it should. A single loop treats all user interactions.  A single loop treats data acquisition.  A single loop about the transformation.  I hope that this would help, but obviously made things much more complex.  I created a queue for each loop.  I didn't get the full project, but it seems that everything has run very well where I stopped.  However, one of my States I did not queue receive queue and I have no idea why or where coming.  There is an error in the variant data that says

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    The other weird thing is the number of items in the queue jumps very quickly when I do almost anything.  I don't know if it's common.

    Before I post pictures or whatever it is, I would have an idea about this error.

    Also, I think I saw this in a previous post about the BAU, but I would like to ask a question.  Attached are two photos.  Queue 1 is the way I put things in place.  Queue 2 is the way I saw things in place.  Can someone tell me if the queue 1 is the wrong approach and why?

    I realized what happened.  The other loop was not handled properly and sent the random State of the main loop.

  • Instead of using the structure of the event with the producer consumer?

    I used the architecture of producer-consumer in the past to control a state machine with the structures of the event.  I'm working now with the basic version of LV that does not include the structure of the event.  Can anyone recommend alternatives to the use of the same architecture in this case?  Thank you, David

    Before the introduction of the structure of the event, the only option was the election.  Control terminals are in a time loop (the producer) with shift registers and a wait, usually about 100ms.  At each iteration of the loop, the control's current value is compared to the previous value.  If it has changed, and then take appropriate action.  Andrey suggested, queues are a good way to pass information between the loops.

    It works for the equivalent of the value change events.  Things like mouse to top or filter events were much more difficult or not possible.


  • If you have any with the itemrender have a control label and onther a gri data

    Hi friends,

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    In my application, I used list control. The list control's item converter. In my case if I click on the name list control, releated data corresponding to the data grid need to view and control the list as label.

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    < s:Label id = name = "{data .sec_user_first_name + data .sec_user_last_name 'lbl_userhead'} ' buttonMode ="true"color =" #000000 "/ >" "

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    Please help a whole for me...

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    If I understand correctly, you want to display a different set of data in a DataGrid control for each selected item in a list?

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  • Master/slave producer/consumer Feeback?

    We know that in the models of master/slave and producer/consumer can send information of the master loop or a producer to the loop of the slave or the consumer.  But what to get information of the loop of the slave/consumer back to the master/producer loop?  I think it may return some sort of output or a message saying something like "I finished my work successfully.  This can be done with local variables, but is it really a good idea?  Is there another better way?   In addition, in this case can I just use a sub - vi?    I don't know that I always get the PARALLEL treatment offerred by master/slave and producer/consumer with a sub - vi.

    You can use a notifier to send a return message.  You can use a local variable, but unless you know what you are doing, you might encounter problems with race conditions.

    Sub - VI have nothing to do with producer/consumer architectures.  You can do a p/c with or without sub - VI.  Sub - VI is a way to break the code in significant functional blocks.

  • How to stop an acquisition continues in producer/consumer


    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?

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    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.

  • acquisition and recording of analog data with producer consumer model

    Someone on this forum, in a separate last week discussion, suggested that I use the producer model consumer data acq.  My ultimate goal is to acquire analog channels 1-4 continuous data, display graphical band style and save the data on the boot disk when the user presses the 'Start Saving' button (and will continue to display recorder cards).  Economy will stop when the user presses the button "Stop Saving" but strip map will continue to operate.

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    Thank you.


    Looked at your code, and you are right.  It won't work.

    Take a look at this example:

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  • Producer-consumer mode, PDM and Acquisition journal continues

    I created a VI based on events to control the parameters of data acquisition. I created a queue of producer-consumer in TDMS file in the loop of the consumer.

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    Thank you

    This is certainly not how I would like to start to create a Soft Front Panel for a task to HAVE.  Leave to file logging asside for now (appearing, it is actually very easy to add later.)

    As food for thought - and because that create a FPS really involves a slightly different thought where you started I whip a 'start' of a FPS.  It also shows how to create a simple API around a 'resource Module.   (Just a natural extension of a "motor action - if you haven read the nugget of community is always a good read.")

    What I compressed is not complete - but you should get an idea of what to expand and where.  You could even have there more faster here than when you are now.

    An approach like that can really help when you go to unwind the problems as you mentioned in your code when you are unable to move around the information that the GUI can't really do use anyway and not IS NOT NECESSARY at this level.  the guys from 'Computer Science' will use terms such as 'Hide data', "Functional Abstraction" and "Encapsulation".

    The capture below is meant to tease the project so that others can get the idea of code - (sorry no LAVA TDC today! )

  • producer-consumer: optimize data acquisition rates

    I have a type of producer-consumer of application in which a single loop continuous waiting there and reads data from the card and another loop readings/backups of data. But besides a loop more trace data. The number of channels and real-time scanning is set by the user, the time it would take to save, view, and analyze each data block (an iteration of analog-to-digital reading) may vary according to different parameters.

    I'm putting 'number of samples to get' big enough on analog/digital playback to the beginning so I don't get the overflow of queue. Now I would like to adjust automatically when the program is running so I understand any overflow from the queue and at the same time the data are not exposed in the huge chunks at a time. Someone did he do this kind of thing before? For now, the only idea I have is to read the number of items in the queue at all times and use a mathematical formula to increase or decrease the number of samples.


    The number of items in the queue of streaming and using a mathematical formula to increase or decrease the number of samples is a good method. You can also use the decimate 1 D table function to display a smaller grouping your data if your problem is that you do not want to display huge chunks of data at the time.

  • First try the producer consumer Architecture: continuous play and dynamically update settings.


    I am currently working with two instruments; an Agilent E3646A and a NI 6212 BNC. My goal is to have the 6212 continuously take measures according to predefined parameters while the E3646A parameters can be continuously updated. This combination simple instrument aims to help me learn the manual architecture; continuous measurement, output dynamic controls and instruments more will be added in the future.

    I've already posted on a similar, but more complicated configuration ( and was advised to try the producer consumer Architecture.) I found the documentation on the website (,, searched the forums and built my own VI. While my first attempt at a producer consumer Architecture has solved some of the problems I had when I posted on the subject, however, new questions have been raised regarding the reading and adoption of the VI.

    I am currently able to run the VI and update the settings on the device. Previously, I'd get a freeze while the instrument has been updated and could not switch settings until it was done. This has been resolved, although that reading updates only when a parameter has been updated, although it is outside the structure of the event. In addition, the Stop button does not in any context. I also got occasional mistakes on the part of Deqeue, but the major part of the sentence is error-200279 'A tried to read samples that are no longer available' to DAQmx Read. I realize that there is a problem in my loop of producer but have not been able to find a way to solve it.

    This is my first attempt at a producer consumer Architecture and already I can see that it is a powerful tool. I read as much as I could and looked at examples, but should have some problems at the beginning. Would be very grateful of any advice so I can take full advantage of the architecture.

    Hope to hear from you,

    Yusif Nurizade

    You're going to overflow this buffer, unless the events are generated faster than "sample rate/number of samples.   Period.  Nothing could be simpler.

    You don't need a local to stop your curls.

    Try something like this attachment.  I simply moved the structure of the event in its own loop dedicated since it had nothing to do with acquiring data at all.

    Data acquisition loop stops very well when you destroy the task and destrying the stops of power queue (sending the default values of the queue for the power control) for EXAMPLE, to ADD a group of setting 'Safe shutdown' to a 'package' and it wire to the Center terminal (Prototype).

  • Error of timing architecture producer/consumer


    I use architecture of producer/consumer for the acquisition of measures of constraint by using several channels. Also, I am interested to write data all 1 minute given that the program should be run for a month. Currently, I get a 200279 error whenever I increase the time of 10 sec. To control the execution of the loop of producer, I use 'weight up to the next multiple ms' function. According to the error message, I tried to fix the samples to read without increasing the frequency of data acquisition, but I still get the same error.

    Thank you


    Your was not included, so we do not know what is happening there.

    What is the rate of acquisition for your data acquisition task?  DAQ hardware do you use?

    Have you tried to increase the size of the buffer?  There is a property node that can define it.

  • Master/slave event Structure vs. State Machine


    First some background to the question (skip this paragraph if you are simply interested in the question). I'm relatively new to Labview, after only a few months of coding with Labview and LabVIEW Core 1. Being one of the only people in the company who now knows Labview I have been challenged with the creation of a relatively complex application that will perform a selected ten or to view different tests with customizable options, display, analyze and deliver and automate reports.

    For the application I am writing I need a GUI with several screens (I achieve with tabs), initially I tried this code with the structures of the event within a machine to States (but as you probably know this was fundamentally flawed, that you can't put structures of the event within the structures of the case) (, or structures of the event), but from here, I spent several hours of searching the best alternatives.

    So my Question is: would recommend to use a master-slave (with the structure of the event and the State of computer, respectively), or simply use to continually voting machine status?

    (Keep in mind I'm going to use this as part of a larger facility of producer/consumer.)

    Thanks in advance,

    Joshua Walker.

    I use a case in my state machine specifically for checking to GUI events.  It is usually a "Idle" State or a specific State to 'check events.  I can also set the time-out programmatically by using a register shift, just in case I need to do a quick check (some small timeout) or wait for a user to press a button (timeout is - 1).

  • How to build a table in a master/slave relationship?

    Hello NOR community,

    I can't build a table in a master/slave relationship. I want two paintings to be built for a fixed amount of iterations, once press the 'pressurization '. (This data acquisition would occur only once per program). I am new to Labview so I apologize in advance for my layout disorder.

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    Master slave relationship is even necessary here? How to pass a variable (pressure main once a loop without getting stuck in a nested loop situation?

    Here is a small example, just to show an idea (many things is not optimal in this example!). Based on your VI you have attached, you miss a lot of basic concepts of LabVIEW, you go through online training.

  • Producer / consumer set loop of dynamic data item type

    Hey all,.

    I do a simple exercise of producer / consumer in a loop. In my loop of producer I audio Aqcuerir and in the loop of consumer I'm projecting on a chart

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    I knew no better way to get the kind of data that I used to just take an another "acquire its" Express VI and which hang. But that may not be the only way to get there, right?

    Note: I know that I might not need to use a producer / consumer design tend to do, but I need to get hold of technology for school work so I came with this exercise just to get a hang of it.

    Thanks in advance,



    You just need to feed the correct data type in this entry, which you did by getting the output of a second acquire its Express VI.

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