LV producer consumer and TestStand

In the TestStand process model, I've replaced the original Get UUT Serial Number dialog with a custom dialog that has some additional fields, and will (eventually) allow the operator to BarCode scan the serial number.
I'm thinking about using LabVIEW's template for Producer/Consumer. I basically want to allow the user to hang out at this dialog until the click on either "START" or "CANCEL". They can tab to the different fields, and Scan in the serial number if desired. What types of 'events' would I want to capture? Is this even the right design pattern for this situation?
Also, this dialog needs to be modal (in front of TestStand executive).
Thoughts?

mrBean,
By custom dialog do you mean a seperate VI that you open and show the front panel when the step executes?
If that is the case the producer consumer might be overkill. From what I've seen one of the main reasons one would use this pattern is to seperate the acquisition loop from the data record loop. In that manner the data recording doesn't slow down the data acquisition. I've used a wedge type barcode scanner in the past and it is pretty easy to impliment.
On a side note I really enjoy reading your posts on both of the forum boards. I too at some later date will be creating a custom operator interface using LabView and your questions have been really helpful in my formulation of a plan. Thanks
Using LabVIEW 2010SP1 and TestStand 4.5

Similar Messages

AJAX producer/consumer and JAVA producer/consumer in same project

I've already successfully integrated and customized the code for both an AJAX and JAVA producer/consumer client in JMS (using ActiveMQ as the JMS broker and Tomcat as the webapp container). While both have been working well in separate projects, unfortunately, I'm having a bit of trouble trying to integrate them for the purpose of running an AJAX message listener and JAVA message listener in the same project.
What I'm trying to do is have JAVA act as the failover for when the AJAX JMS consumer is not listening (i.e. when the browser is closed). When a browser client opens, the (constantly running) JAVA client can ignore the messages... but... when no browser client is initialized, the JAVA client should respond to the messages on behalf of the AJAX client.
I've tried using a ServletContextListener pattern, which I was hoping would "automagically" launch the JAVA listener via its main method, whenever the Servlet gets initialized (i.e. it would auto-start when Tomcat gets restarted, or, anytime the Servlet gets redeployed) but it seems Tomcat is not thread-safe and this might be causing some problems.
In any case, I can't seem to get the JAVA client to reliably start running and stay running for the lifetime of my AJAX client (webapp .war), and without including them in the same project and same J2EE container sharing the same ServletContext, I don't know how its possible to ensure they are running and starting and stopping at the same time.
Is there perhaps a better way to accomplish this?
Edited by: bcmoney on May 17, 2010 1:25 PM

I've already successfully integrated and customized the code for both an AJAX and JAVA producer/consumer client in JMS (using ActiveMQ as the JMS broker and Tomcat as the webapp container). While both have been working well in separate projects, unfortunately, I'm having a bit of trouble trying to integrate them for the purpose of running an AJAX message listener and JAVA message listener in the same project.
What I'm trying to do is have JAVA act as the failover for when the AJAX JMS consumer is not listening (i.e. when the browser is closed). When a browser client opens, the (constantly running) JAVA client can ignore the messages... but... when no browser client is initialized, the JAVA client should respond to the messages on behalf of the AJAX client.
I've tried using a ServletContextListener pattern, which I was hoping would "automagically" launch the JAVA listener via its main method, whenever the Servlet gets initialized (i.e. it would auto-start when Tomcat gets restarted, or, anytime the Servlet gets redeployed) but it seems Tomcat is not thread-safe and this might be causing some problems.
In any case, I can't seem to get the JAVA client to reliably start running and stay running for the lifetime of my AJAX client (webapp .war), and without including them in the same project and same J2EE container sharing the same ServletContext, I don't know how its possible to ensure they are running and starting and stopping at the same time.
Is there perhaps a better way to accomplish this?
Edited by: bcmoney on May 17, 2010 1:25 PM

Event producer/consumer

hello,
i'm trying to study the differents existing structures (event, state, semaphore ...)
the first is event producer/consumer and i don't succeed to display queue infos it's ok for size queue but not max and
array of elements, what can i do to make it visible ?
another question, where can i find basics examples ( but realistic) using event P/C, event p/c state machine, semaphore, rendezvous, occurence, dynamic regitration .....
if you can reply even just one of requests it would be nice
Best regards
Tinnitus
CLAD / Labview 2011, Win Xp
Mission d'une semaine- à plusieurs mois laissez moi un MP...
RP et Midi-pyrénées .Km+++ si possibilité de télétravail
Kudos always accepted / Les petits clicks jaunes sont toujours appréciés
Don't forget to valid a good answer / pensez à valider une réponse correcte

hello bis,
I just come to find the return element option , but for others questions it's still on air
tinnitus
CLAD / Labview 2011, Win Xp
Mission d'une semaine- à plusieurs mois laissez moi un MP...
RP et Midi-pyrénées .Km+++ si possibilité de télétravail
Kudos always accepted / Les petits clicks jaunes sont toujours appréciés
Don't forget to valid a good answer / pensez à valider une réponse correcte

First attempt at Producer Consumer Architecture: continuous read and dynamically update parameters.

Hello,
I am currently working with two instruments; an Agilent E3646A and an NI 6212 BNC. My objective is to have the 6212 to be continuously taking measurements according to predefined parameters while the E3646A's parameters can be continuously updated. This simple instrument combination is intended to help me learn the necessarry achitecture; continuous measurement, dynamic output control, and more instruments will be added in the future.
I've previously posted on a similar, but more complicated, setup (http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/Split-second-lag-when-controlling-two-instrum... and was advised to try the Producer Consumer Architecture. I've found relevant literature on the site (http://www.ni.com/white-paper/3023/en/, https://decibel.ni.com/content/docs/DOC-2431), searched the forums and constructed my own VI. While my first attempt at a Producer Consumer Architecture has resolved some of the issues I was having when I first posted on the subject, however, new issues have arisen with regard to reading and stopping the VI.
I am currently able to run the VI and update the device parameters. Previously, I would get a freeze while the instrument was being updated and could not toggle parameters until it was done. This has been resolved although the read only updates when a parameter has been updated although it is outside of the event structure. Furthermore the Stop button does not work in any context. I've also gotten occasional errors regarding the Deqeue Element but the bulk of the trouble is Error -200279 "Attempted to read samples that are no longer available" at DAQmx Read. I realize that there is a problem in my Producer Loop but haven't been able to figure out how to resolve 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 the relevant examples but expected to have some issues in the beginning. Would really appreciate any advice so I can take full advantage of the architecture.
Hope to hear from you,
Yusif Nurizade
Solved!
Go to Solution.
Attachments:
DCe3646A_DAQ6212_Prod_Con_4_13a_2014.vi ‏89 KB

Jon,
Thank you for the response and the suggestions.
I created the Local Variable for the Stop Button and moved the original into its own Event Case. It is now able to stop VI execution although I get Warning -1073676294 which I understand to be the buffer issue. The warning says that this was incurred on VISA Open for the E3646A's Initialize VI which is outside both loops, however, which I don't understand.
I tried increasing buffer size by decreasing the Number of Samples as per suggestions I found on NI forum threads. I've brought it down as low as 1 but the graph still only updates when an Event occurs and I keep getting the same buffer error. You suggested that the problem could be that they are in the same loop; does this mean that the DAQmx read should be outside both Producer and Consumer Loops or moved into the Consumer Loop? I found a couple of links ( http://forums.ni.com/t5/LabVIEW/Producer-Consumer-Design-Pattern-DAQmx-Event-Structure/td-p/2744450 , http://forums.ni.com/t5/LabVIEW/Producer-Consumer-Architecture/td-p/494883 -first response) on dealing with an Event Structure that my own VI is based. Alternatively, I found another link ( http://forums.ni.com/t5/LabVIEW/Producer-Consumer-Design-Pattern-DAQmx-Event-Structure/td-p/2744450 - first response) on a DAQmx Read with an Event Structure that places the graph in the Consumer Loop.
The core of my purpose in setting up this Producer Consumer Architecture is so that I could read continuously while the instrument parameters are updated dynamically so it's very important that I understand how this works. I am particularly struggling with how the Event Structure is controlling the While Loop's Execution.
Hope to hear form you,
Yusif Nurizade
Attachments:
DCe3646A_DAQ6212_Prod_Con_4_14a_2014_Edit_I.vi ‏90 KB

Input and output on same device, producer/consumer structure

Hello interested people,
I have a question about using the same device for both digital inputs
and outputs. I have written a simple program of one while loop
that continuously polls the device, processes, and requests. I
have addressed the device using two DAQmx Asst. and I have attached
them with their error in/out cluster terminals to provide data flow and
eliminate the chance of addressing the devices at the same time (which
produces an error). Now I want to change this program structure
to a producer/consumer loop foundation with state machine.
In this design, I will have the DI in the producer loop and the DO in
the consumer loop, under one of the states. I can't simply
connect the error in/out ports in this configuration, so my question is
how to avoid the error caused by addressing the same device
simultaneously with two different tasks (input and output)? I
have attached two VI's, the "One Loop" vi is the original configuration
(simplified), and the Producer-Consumer vi is a NONSENSICAL program
that simply represents the desired configuration. (I don't need
any comments on the programming of this vi, it is only an example for
illustration of the problem).
I am thinking about bundling the input data and the error cluster, both
from the PXI 6528 DI, into one cluster, queueing that up, and
unbundling the de-queued elements for some kind of data flow between
the producer loop and the "Request" state of the consumer loop.
Is this the right approach, or am I barking up the wrong tree?
Thanks
Attachments:
One Loop DO DI.vi ‏102 KB
Producer-Consumer DI-DO.vi ‏106 KB

Hello,
It sounds to me like you really have two modes:
1. user interface actions determine execution
2. user interface is locked, and execution is automated.
I think it would make sense to use the producer consumer for an architecture. Basically you would do the following:
1. program the producer to handle the user interface as you normally would.
2. provide one additional event case in the producer which would be your "automated handling" case. In that case, you could put a state machine which could run until whatever conditions were met to put your program back in "user interface mode".
Keep in mind that you can use custom USER EVENTS to programmatically generate events ie. you can trigger the start of your "automated handling" form anywhere in your code at virtually any time.
I think this would allow you to take advantage of the producer consumer architecture in its intended spirit, while integrating an automated routine.
I hope this helps!
Best Regards,
JLS
Best,
JLS
Sixclear

Jms Adapter Consume and produce

Hai guys,
i don't know anything in soa. i have got a usecase which is to
1) Read a .csv file
2) Send it to a bpel (in bpel do nothing to payload). Again i have to send the payload to jms adapter( which i dnt knw how )
3) From the same jms adapter passing the payload to mediator
4) Pass the input to another jms( jms2 ). from jms2 pass the payload to another bpel
5) from bpel to db adapter
am using
Oracle jDevloper 11.1.13
Weblogic server is a 10.3.6
my problem is how to create the same jms in two ways like consuming and producing
Thanks in advance
Edited by: Beckyard on Sep 26, 2012 9:49 PM

Hi,
Why do you need 2 JMS queues? Can't you consider following pattern?
Read .csv --> BPEL --> JMS Q
JMS Q --> Mediator --> BPEL (only if some payload processing required) --> Db Adapter
Assuming the above pattern, you'll have to develop 2 processes (in your pattern 3 processes).
- One that will enqueue the data in JMS in which the JMS Adapter will be placed in the External references and will be invoked with Produce operation.
- Another process in which Mediator will consume the message using Consume operation from JMS and pass it to BPEL for inserting into database. In this case, JMS Adapter will be placed in Exposed Service swim-lane.
Let us know how you proceed.
Regards,
Neeraj Sehgal

Producer consumer with analog and digital inputs and outputs

Hi everyone,
I am working on a control system program for some practical test work. Currently I am working on the data acuisition component of the Labview program. My architecture is produced-consumer loops with a que. My system will have analog inputs, analog outputs, digital inputs and digital outputs. It's not a time critical sytem, but I would like all of the data acquisition to be synchronised. I have attached my program as it is at the moment. I am having trouble getting all of the data into the que since I have two data types. Also, I'm not sure if i've synchronised the four read/write sequences correctly. I would greatly appreciate if somebody could take a look at my program and give me some advice. Thanks in advance.
Solved!
Go to Solution.
Attachments:
control_v2_DAQ loop.vi ‏46 KB

Robert, the specific error that I get is:
Error -200462 occurred at DAQmx Start Task.vi:6
Possible reason(s):
Generation cannot be started because the output buffer is empty.
Write data before starting a buffered generation. The following actions can empty the buffer: changing the size of the buffer, unreserving a task, setting the Regeneration Mode property, changing the Sample Mode, or configuring retriggering.
Task Name: Heater testing lab digital outputs
This error occurs at the 'DAQmx write.vi' function. I just want to sent one sample per second, for each channel. I would like the producer and consumer loops to each run once every second.
I have attached part of my code with just the data acquisition and writing. Any help would be greatly appreciated.
Attachments:
control_v2_ML_simple.vi ‏83 KB

Producer Consumer Subpanels, User events and DAQ

Hello All,
I am working on a Producer Consumer application and have beed looking at subpanels for user navigation. The application needs to be capable of responding to user generated events but also manage data received from attached data acquisition and control hardware. This is a 2 part question.
I need to implement about 15 screens in this application and have started integrating subpanels. I need to be able to navigate from one subpanel vi to another using subvi buttons but dont understand how to build this functionality. Can I build functionlaity so that when I click on a subpanel loaded vi's button it will load the vi referenced by that button and the original dissappears.
I have a 3 loop producer event template consisting of (1)data acquisition producer, (2) user event producer and (3) consumer loop but theres not much detail, are there any reasonable templates out there? I have seen the data- consumer and user-consumer but no mix of all 3.
Advice appreciated
Chris

I use subpanels to host my display vi's and control them dynamically. I would have a loop or vi process that manages your subpanel. You could use user events, queues or notifiers to send messages to this subpanel manager to perform the basic functions such as loading a vi into a subpanel, removing a vi from subpanel (you can remove and stop the vi or keep the vi running in the background or even make it a floating vi.) A subpanel button can create a local event which in turn could trigger a user event or message to the subpanel manager. I have attached my subpanel manager to give you some ideas...
Attachments:
Subpanel Manager.vi ‏39 KB

WSRP - Pass Custom Data between Consumer and Producer

Hello All,
I am having a couple of queries with respect to Custom Data Transfer. Consider I have a Map of values which I need to transfer between both Consumer and Producer.
For eg: the map that Consumer sends would contain "firstName", "lastName", etc... On the other hand Producer needs to do some business function based on the data and add more values to the map like "rewardPoint" etc....
On Consumer Side:
I have choice to use Backing File or IGetMarkupInterceptor to implement the preInvoke to pass the data using SimpleStateHolder.
Question: I am not able to send a simple Serializable POJO Object... I can only send primitive / default java objects like Strings, Maps of String etc. Is my understanding correct?
On Producer side:
I am able to receive the Custom Data from request. No problems. Now how to send more data from Producer to consumer. I need to add the "rewardPoints" into the map and send back.
My understanding is that if the Producer puts any values into StateHolder objects, Consumer will receive it in IGetMarkupResponseContext object in the Interceptor's postInvoke method.
Question: How do I get a handle to the IGetMarkupResponseContext object @ Producer end???
Question: Do I need to write some interceptors on Producer end? If so which file I need to use?
Any help / pointers would be greatly appreciated.
Thanks,
Paz

Hi All,
I tried to set the data in the producer using the following command
SimpleStateHolder stateSimpleOuterReq = (SimpleStateHolder)request.getAttribute(MarkupRequestState.KEY);;
          if (stateSimpleOuterReq == null) {
               SimpleStateHolder state = new SimpleStateHolder();
               state.addParameter("name", "data1");
               request.setAttribute(MarkupResponseState.KEY, state);
I am not able to retrieve the same in consumer.
The above is a WSRP struts request.
I also tried setting the data by unwrapping the request in producer and still value is null in consumer :-(
          HttpServletRequest requestq = (HttpServletRequest)((HttpServletRequestWrapper) request).getRequest();
          SimpleStateHolder stateSimpleReq1 = (SimpleStateHolder)requestq.getAttribute(MarkupRequestState.KEY);
               if (stateSimpleReq1 == null) {
                    SimpleStateHolder state = new SimpleStateHolder();
state.addParameter("name", "data1");
                    requestq.setAttribute(MarkupRequestState.KEY, state);
Please help me in resolving the issue. Correct me if i am doing anything wrong.
Thanks
T. Deena
Edited by: user11261911 on 12/06/2009 19:49

Producer loop and 2 consumer loop for acquisition and process images

Hello everybody,
I'm quite a newbie in Labview 2011 on Windows 7.
Those are what I want to do :
Step 1: When the objects fall with velocity around 2 to 5 m/s, images of these objects will be acquired continuously from PCIe 1433 with Basler spL4096-39kc.
Step 2: The processing of the images continuously in the same time with step 1 will find the datas of the objects in images as colors, patterns and locations. If the patterns and colors at location are as the same sample, the elements in Boolean data array are true.
Step 3: Every 01 millisecond, values from Boolean data array will be read, the valves of nozzle will be opened if the values are true.
My question is what is the best way to do my tasks ? I couldn't find any example of program in Labview and I think I use producer/consumer architecture for step 1 and 2 but I don't know how can I set up producer loop for step 3 and transfer Boolean data array from step 2 to step 3 ?
Thank you for reading and help me !

Dear Eric-J,
Thanks for your reply. I want sort the pellets that have 6mm diameter. The pellets were fed in a single layer by a vibratory feeder with a flat-bottom trough, 400mm wide that was supplied with the feeder . The pellets dropped off the end of the feeder onto a chute with 40 parallel U-shaped grooves. Images of these pellets will be acquired continuously. I make the sample from image that was acquired. I use NI Vision for processing of the images. If the patterns and colors of pellets are as the same sample, the elements in boolean data array are true. As you thought, I would like to interpret data every millisecond and open/close a valve based on the boolean array. The air valve sends a burst of air for 2 - 3 milliseconds to an air nozzle that diverts the pellets into the appropriate channel.
What are your ideas for this task ? Could you explain more clearly about "a real time system" and "determinism" for this task ?
Thanks and best regards

State Machine and producer consumer design patterns

Hi!
In my application I am using state machine(for top level VI) and producer consumer(for subVIs) design patterns throught out.
If there is no activity on the front panel for 1min then the ideal state is invoked. Following are the situation of the ideal state:
1. It checks for any hardware present on the network . If no hardware is found on the network within 1 min then the application and LabVIEW exits.
2. While the ideal state checks for the hardware, and user clicks on any front panel button then it should exit the ideal state. The control
should be in the respective button state.
I am able to achive the point#1 mentioned above but could not get the point #2 to work. I am including the snap shot of
the state machine(default case) and prouducer consumer(deafualt state).
Each screen has the concept of the ideal state. The only additional step in the subVIs is that when the ideal state is reached and the time has expired then it will close the subVIfront panel.It will go to the exit state of the Main(top level) VI. Thus closing the application and quitting LabVIEW.
Any ideas or suggestions. Will multithreading and notifiers help?
TIA
Rachana
Attachments:
Sanpshot_Of_Design.zip ‏75 KB

Hi Rachana,
I was thinking about using event structures wherein there would an event case that would handle any value change event for any of the buttons on the front panel. But before suggesting that, I would need to know more about the Ideal State subvi( more specifically, how is it checking for any hardware present on the network and where is the one minute wait coming from?).
Please feel free to respond to this post with your questions/comments.
Regards,
Ankita A.

How to build a stable, reliable application with consumer and producer

Hi all,
As a frontend solution, Flex is really powerful and fascinate. On the other hand, it inevitiably needs to exchange data. And I am trying to find a good way to build a stable and reliable application.
Here's the workaround. On server side, blazeDS or LCDS is involved and on frontend component Consumer and Producer are used to interact. A group of users cooperates on the whole processing. Everybody will send an update once he finished current job.
Of course each frontend need to subscribe first. But if one frontend is disconnect temporarily and other frontends send message to backend during that time, how can the disconnect one get message it missed? How can I fix the inconsistent status?
Thanks and regards,

Hello meshgraphics,
Your reply is useful, but feasible I have to say. Creating DB tables, updating entries and synchronizing contents involve a lot of work. As we can use blazeDS and LCDS, that'll be good option. From online help, it doesn't explain what will happen if consumer disconnects temporarily which is very important to me. If some messages are missed, the whole process can't move on smoothly.
Simply speaking, I hope below issues can be solved with blazeDS or LCDS:
1) how to ensure messages are delivered to subscribed consumers if they are temporarily disconnected?
2) how to recover work if consumers are thoroughly disconnect?
Thanks and regards,
Felix

Measurement and control via Producer/Consumer

Hello folks,
Iam trying to realise an automated projekt, for testing an actuator.
It has to Measure the Signals, process them and also has to create signals controling the actuator.
So far no Problem....But,it also has to run trough 3 or more Test-cycles of wich each has different ControlSignals.
(example: Test1 - input: 40VSin(40Hz), Test2 - input:Triangle, Test 3 - input: 100Vsin(100Hz)
It still doesnt sound quite difficult, but as an LabView beginner, i´m having a lot of trouble finding the Right Structure to realise all This. normally i use SPS systems, but this time it has to be Labview
Had some trys an hav uploaded them.
But The Producer/Consumer Structure makes some Problems. It doesnt give out any Signals from the ProducerLoop. :/
Is there any outher way programing Labview more efficient for that Problem ?
Sorry 4 the bad English
Greetings
Solved!
Go to Solution.
Attachments:
ProcessTest2.vi ‏129 KB

MarioMueller wrote:
Hello folks,
Iam trying to realise an automated projekt, for testing an actuator.
It has to Measure the Signals, process them and also has to create signals controling the actuator.
So far no Problem....But,it also has to run trough 3 or more Test-cycles of wich each has different ControlSignals.
(example: Test1 - input: 40VSin(40Hz), Test2 - input:Triangle, Test 3 - input: 100Vsin(100Hz)
It still doesnt sound quite difficult, but as an LabView beginner, i´m having a lot of trouble finding the Right Structure to realise all This. normally i use SPS systems, but this time it has to be Labview
Had some trys an hav uploaded them.
But The Producer/Consumer Structure makes some Problems. It doesnt give out any Signals from the ProducerLoop. :/
Is there any outher way programing Labview more efficient for that Problem ?
Sorry 4 the bad English
Greetings
your architecture is hard to follow. i think you can do this with a state machine..write out your test requirements in steps and what requirement you need to transition. be more specific in describing your problems (error messeges?)..

Progmatically stop vi with producer/consumer architecture

I can't seem to get my VI to fully stop, so that I can go on to do some more things in the program. I am trying to progmatically stop the vi (pictured below), so that I can return to my main gui (not pictured). The main gui just consists of a login, exit test system, and run test. Once the user presses run test, the vi pictured below opens.
I am using a producer/consumer architecture with a state machine. The problem I run into is that when I press the "Main Menu" button, it should close the pictured vi and return to the main gui. I tried using the vi server, and when the user presses the Main Menu button, it fires an event and then it goes to the Stop state in the consumer loop, which opens a reference to the vi's (one for the strip chart vi and another for the gage vi), closes the front panel using an invoke node and then closing the reference. I also tried adding in the abort vi method after the close front panel and it still gave me the same result.
Here is the catch, it does close the vi's, but it does not stop the while loops (producer and consumer), or it stops only one of the loops. I thought of putting in a constant in the event structure for when the Main Menu event is fired, but that will stop the producer loop before the consumer loop reveices the info to go to the stop state, so the consumer loop does not end.
I also tried a "dummy" control that was connected to the comsumer loop Stop terminal (for the while loop), and then progmatically changed the value in the stop case to true and then read that value in the producer loop to, hopefully, stop both loops, but it did not work either.
I am sure that it is something so stuipidly simple that I cant see it right now
Kenny
Kenny
Attachments:
test system.gif ‏252 KB

Hi Kenny,
I think of two solutions to your problem. First, use the message queue to pass the message "stop" or something from producer to consumer or second (and I think, better), use occurrences. I made a little draft how it could work.
You have to pass the occurence- Refnum to both VIs, the producer and the consumer, when the producer finishes execution, then use "Set Occurence".
In the consumer blockdiagram you react on the generated occurrence.
If you set in the VI- properties "Open Frontpanel when called" and "Close if originally..." the VI Frontpanel should disappear itself when execution is stopped.
Hope this helps,
Dave
Message Edited by daveTW on 08-14-2006 04:53 PM
Greets, Dave
Attachments:
occurrence 1.png ‏1 KB
occurrence 2.png ‏5 KB

How to change the transmission rate of data flow in producer/ consumer pattern

Hi All
I am new to labview and trying to design a application to transfer image data in different rates, that means I can change the transfer rate in the transmission process. In fact,I refer to the the Queue Basic.vi to achieve this function by Changing the delay value of dequeue and enqueue.The program is divided into three parts:
The first part is the sender in vc used to split and send image data.Data size is 226kb and each time we send a 1kb packet;
The second is labview rate-change part，use producer/ consumer pattern and queue to transfer data;
The third one is the receiver in vc,receive data in sequence and synthetic images.
The entire transfer process is: image data was sent from the sender to producer loop through DLL, then enqueue--dequeue in consumer loop--DLL--receiver.The sleep time in vc sender is equal to the delay value in producer loop and this makes it look like the data generated as in the loop.
Now this is where my dilemma is：
When transferring data, if the producer loop and consumer loop delay value are equal(both 20ms), I can see image synthesis at a constant speed and no data lose; if I change the consumer loop delay value and make it greater than the producer delay(one is still 20ms and another is 50ms),that means receive in a lower rate and store data in queue. I can see Elements in Queue
increase but the image data randomly lost, and the image synthesis speed is not reduced.
My question is why image data loss and I can't see the image synthesis speed reduced when change the delay value in consumer loop?
Do anyone know how to solve the problem? Are there any examples I can refer to? Any suggestions are greatly appreciated!
Attachments:
image1.JPG ‏56 KB

thisoldman,
I don't have '/usr/lib/modules/3.17.3-1-ARCH/build/Documentation/VGA-softcursor.txt' on my file system. Does it contain the info about changing the blinking speed?
P.S. The other two links I found yet before starting this thread. I only found in them the recommendations about changing "the color and shape of the cursor and turning blinking on/off" (as I mentioned in the original question). Did I miss the info about the blinking speed?
PPS: I found the vga-softcursor.txt here: https://www.kernel.org/doc/Documentatio … cursor.txt
But that file doesn't tell about changing the blink rate either.
Last edited by nbd (2014-11-23 20:55:41)

LV producer consumer and TestStand

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