Calling producer/consumer subvi using main vi for image grab acquire

Hi everyone,
I am not sure if I get the producer/consumer concept wrong. I tried to write a producer/consumer subvi that simulate continuously grab acquire image. When I call the subvi from the main while loop with a main vi, it seems to run into a infinite loop. I am wondering does anyone know how else can I activate a producer/consumer subvi using main vi? Thanks in advance.
Kind regards,
Han Yen
Solved!
Go to Solution.
Attachments:
MainTrial.vi ‏7 KB
ProducerConsumerGrab.vi ‏18 KB

Hi Han Yen,
a few remarks :
- your Top VI has no function what so ever. So skip that.
- your image queue has no name, so that gives problems from the minute you're going to use more queues.
- It does not matter which command you send to the queue, it will start the bottom loop anyway
- You don't have a check whether "live trial" is true yes or no, so everytime you switch it from T=>F or F=>T is will activate the command.
I've tweeked your producer-consumer. Maybe this will give you an idea. I put some remarks in some places
Kind regards,
- Bjorn -
Have fun using LabVIEW... and if you like my answer, please pay me back in Kudo's
LabVIEW 5.1 - LabVIEW 2012
Attachments:
ProducerConsumerGrab.vi ‏21 KB

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using synchronized.
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class Q has 2 synchronized methods,one to get() and one to put().
class Producer and Consumer both have a reference to this object.
Now look at the main() class ProducerConsumer,which instantiates Q
and passes this reference to the Producer and Consumer.
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in a continous loop.This means that now the Q object has a lock
by the Producer object.
In that case,how can the Consumer object call the get() method.
The Q object is locked by the Producer isnt it? (as the producer
has invoked the put() and this is in a continous loop).
The output shud be:
Put 1
Put 2
Put n
but the output I am getting is:
Put 1
Get 1
Put 2
Get 2
How can this be possible?
How can the Comsumer call get(),if the Producer has locked the object
and has not released it as the synchronized put() is in a continous loop
Has any one understood my query?
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Date             Time       RTD1 RTD2      RTD3   CO2    Flow
5/26/07      5:20:01.25       57         56         56.5      100       0.5
5/26/07      5:20:01.30       57         56         56.5      100       0.5
5/26/07      5:20:01.35       57         56         56.5      100       0.5
Attachments:
Producer-Consumer From Scratch2.vi ‏75 KB

Okay, I've put it in a For Loop and it will connect now. However, whenever it runs the time stamp increments for a couple seconds and then it just repeats. How do I correct this?
Attachments:
Producer-Consumer From Scratch2.vi ‏88 KB
pleasework.txt ‏20 KB

Producer/consumer w/ScanEngine issue

All,
I have a large VI implemented with producer/consumer architecture using 10 events and uses conditional disables to select the data acquisition hardware. The application is being developed in LV2009 with FPGA & RT on XP. The application is intended to acquire and control analog signals in a cRIO-9073, but early development is done using LV simulated signals. I can switch back/forth between the different configurations quickly & easily. In the simulation mode, the front panel, controls, events, etc; all behave as one would expect. When the conditional disable is changed to use ScanEngine and cRIO modules, then a very primary control fails to generate an event and does not function. All other controls that can be tested are functional and generate their events. I am at a loss and seeking suggestions on techniques to diagnose & fix the problem. The application behaves as if the 'event structure' for primary control gets corrupted or some size threshold is been exceeded. The whole concept, scanEngine based and simulated data, were functioning several days ago prior to numeruous edits and I can revert back to not using the scan engine and cRIO hardware with simulated data to validate correct function, but that is not the intended final path. At the present time, I am stuck and looking for ideas. All suggestions will be considered and appreciated. The applicatiion is company proprietary and can't be posted. Thanks in advance.

I can definitely understand your confusion, and on the surface it seems like everything should transfer over. However, when using simulated data you won't get errors that can occur once you introduce hardware. Errors can prevent events from occuring, there is also the issue of timing, to see if when using actual hardware, the timing causes issues. As I menationed before, there are a hundred different reasons why it would work with simulated data, but not actual hardware. Please let me know if you need further direction in your troubleshooting.
National Instruments
Applications Engineer

Running subVI in parallel with itself using producer-consumer pattern

I'm using the procuder-consumer pattern to create what I call threads in response to various events much like in Producer Consumer with Event Structure and Queues
I have several physical instruments, and would like to run the exact
same test in parallel on each of the instruments. I have a subVI
that takes as inputs a VISA resource and a few control references among
other things and then performs the desired experiment. I have a
separate consumer loop for each physical instrument, with this subVI
inside each consumer loop.
My test VI worked great; each consumer loop was a simple while loop
incrementing a numeric indicator (not using my real subVI above).
However, my real program can only run one consumer loop at a time much
to my dismay. Reworking my simple test VI to use a subVI to
increment the indicator rather than just explicitly coding everything
resulted in the same problem: only a single consumer loop ran at a time
(and as I stopped the running loop, another would get a chance to
begin). The subVI in this case was extremely
simple taking only a ref to the indicator and a ref to a boolean to
stop, and incrementing the indicator in a while-loop.
Is there a way around this? Now that I've spent the time making a
nice subVI to do the entire experiment on on the physical instrument, I
thought it would be fairly trivial to extend this to control multiple
instruments performing the same experiment in parallel. It seems
only one instance of a given subVI may run at one time. Is this
true? If it is indeed true, what other options do I have? I
have little desire to recode my subVI to manually handle multiple
physical instruments; this would also result in a loss of functionality
as all parallel experiments would run more or less in lock step without
much more complexity.
Thank you.

You need to make your subvi reentrant. Then it can run several instances at any time with each instance occupying its own unique memory space. Click on File - VI Properties - Execution, and check the reentry execution checkbox. Then save the vi.
- tbob
Inventor of the WORM Global

Calling producer/consumer subvi using main vi for image grab acquire

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