Producer Consumer simultaneous operations at different frequencies

My goal is to do two operations simultaneously.
The desired end result is:
1)      Produce an output signal which oscillates at a specified frequency (1 to 10 hz)(using DIO NI-9403). This signal will cause a solenoid to vibrate at different frequencies.
2)      Monitor voltage on 3 lines in real-time (using analog input NI-9201). This will monitor system response to vibration.
3)      Produce an output signal which oscillates at a different frequency from (1) – producing 1-second HI values 5 seconds apart. This will cause the system to “pulse”; system response will be monitored.
4)      Have a front-panel user interface where: the signals in (2) can be monitored; frequency of (1) can be monitored and changed; and the output on (3) can be monitored and changed.
My efforts so far have been to build a producer-consumer structure. This is my first time using this structure so I may be completely misunderstanding its use. Feel free to correct me if I’m way off target.
The issue I have is the solenoid in the consumer loop (which handles item (1)) is not operating at the desired frequency. It is too slow. I used a 10ms timer for this loop, but instead it is operating about 1 cycle per second.
There may be a much better way to approach this, or maybe my program only needs some minor tweaks. Either way, thanks in advance for your help.
Attachments:
ProdComsLoop Pulser 2-27-14.vi ‏65 KB

Hi BradleyDDC,
It seems from your program that you don't need a producer consumer loop. The only thing you are feeding from one loop to another can be put in one loop, I mean the simulator on button.
The timer does not determine how fast the loop runs in real time. To get more precise timings, we recommend hardware timed operations as opposed to the software timed ones.
Instead of using a digital output signal, you can use a counter output task, here is a knowledgebase, which has an example of what you may want.
Paolo F.
National Instruments
Applications Engineer

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    EngineMon.zip ‏90 KB

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    Message Edited by Kalin T on 03-23-2007 09:57 AM
    Kalin T.
    National Instruments
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    ImplementedProducerConsumer.zip ‏250 KB

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    Attachments:
    OldDesign.vi ‏41 KB
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    Vaibhav wrote:
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    Attachments:
    PCDesign[1]_BD.png ‏6 KB

  • Producer consumer error 200279

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    Solved!
    Go to Solution.

    The DAQ error isn't related to your choice of architecture, although your implementation of it might be hurting you.  It's almost impossible to follow what's going on in your diagram because you have wires running in many directions (try to keep data flowing from left to right), there are local variables all over the place (almost definitely not needed), and there's a lot of code that's not in the image or is hidden in another frame of the sequence.  Normally one would not have the event structure as the consumer loop (as you've done), and it's generally not a good idea to have multiple event structure in the same VI (with rare exceptions usually involving user events).  It might not solve your problem but it would be worth taking the time to clean up your diagram.  Eliminate sequence structures and local variables as much as possible, move some code into subVIs, and straighten out your wires.
    As for the DAQ error: the DAQ board is reading data into a circular buffer, and you're not reading it fast enough, so samples are being overwritten.  The reason you're not reading it fast enough is because you only read a single sample at a time (the DAQmx Read is configured for 1 sample on multiple channels) but you say you're acquiring 10,000 samples/second.  Since your loop won't run 10,000 times per second, you're not reading all the data, which causes the error.  Try configuring the DAQmx Read for multiple samples.

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