Why Ctrl-P restarts a while loop?

Similar Questions

• Suspend and restart a while loop

  Hi all

  After a few TAPI, this is my first post here.

  I need to write a simple VI with three buttons on FP: 'Send', 'do not send' and 'Stop '.

  'Stop' execution of termites. 'Send' starts sending that one CAN frame on NI USB CAN every 5 seconds. 'Do not send' suspend the CAN communication without putting an end to the VI.

  I am not able to find a way to "suspend" the CAN in a loop and then to spin again, I tried to use the queues and the structure of the event, but I can't find a solution to this problem.

  I've been searching the net but without success, for example This example is not appropriate because 'stop' does not work when 'pause' is true.

  Can anyone of you please give me any suggestion / link?

  I'm under LabView 2011 on PC Windows7.

  Thank you

  Andrea

  Thanks Ed, he now works as I expect.

  This is the code:

  

  Do you think it's a good solution or there is a "more clear" solution or better somehow to do?

  Once again, a big thank you to you two

  Andrea

• Why the execution time increases with a while loop, but not with "run continuously?

  Hi all

  I have a problem of severe weather that I don't know how to fix it because I don't know exactly where it comes from.

  I order two RF switches via a data acquisition card (NI USB-6008). One job at the same time can be selected on each switch. Basically, the VI created for this feature (by a colleague) resets all the outputs of acquisition data and active then those desired. It has three entrances, two chain simp0le controls and a cluster table, that contains the list of all the outputs and some practical information to know what is connected (specific to my application).

  I use this VI in a complex application, and I have some problems with the execution time, which increased whenever I said the VI, so I did a test VI (TimeTesting.vi) to determine where the problem came. In this special VI I record the execution time in a csv file to analyze then with excel.

  After several tries, I found that if I run this criterion VI with the while loop, execution on every cycle time increases, but if I remove the while loop and use the funtionnality "Continuous run", the execution time remains the same. In my high level application, I have while loops and events, and so the runtime increases too.

  I someone could explain to me why execution time increases and how can we avoid this? I have attached my VI test and the necessary subVIs, as well as an image of a graph that shows the execution time with a while loop and «run permanently»

  Thanks a lot for your help!

  Your SetReset_DO VI creates a channel whenever it is called.  And that you never delete a task.

  When running continuously, that it's as if it only runs once and LabVIEW has internal mechanisms to close references that will not be used again.  When a VI is used as a Subvi, LV does not know if she will be called again, and lacks these things until the first level VI stops. You have a memory leak.

  Just as you open and close your file outside the loop for, create your channel out of the loop.

  Lynn

• Why a while loop does not start in a flat sequence if I have another loop running in a different sequence of flat?

  Hi all

  Basically, I'm in the order of many device and regulation for that pourpose, I created a sequence of plate to do. Also, at times I have start the potentiostat measures I use too, which follows a sequence and I created a second flat sequence to do this. In a part of my experience, I want to follow the voltage and current of high voltage power supply that is located in the flat main sequence and also read the results I'm getting with the potentiostat simultaneously.

  In the main sequence, there is a constant bollean which triggers the beginning of the secondary sequence. In the framework after it contant Boolean, I have a while loop in which I read 2 analog inputs of the power supply high voltage with my USB-6218 for awhile every 100 m, my problem is that the Boolean constant actually starts the subsequence flat but when it reaches a while loop in which I continue to read the results of the potentiostat , for a reason that the operation does not start until the while loop in the main loop is not finished.

  I communicate with the software of the potentiostat through a driver made by the manufacturer.

  Is it possible to read analog inputs with USB DAQ and simultaneously read the results of the potentiostat?

  Thank you very much

  Without being able to see the code, can only speculate. My guess is that you have probably some data flow to the second loop that depends on the first loop finish.

• What is READ the array returned by the DAQmx meter? How can I know the two functions DAQmx READ data stream in the same WHILE loop?

  I have a question about the order of execution.  In the WHILE loop, I have two things to measure, period and tension using the DAQmx READ functions for voltage and the meter.  In the end, I want to collect these data as points almost simultaneously as possible, as a pair and then send them together to another piece of code (not shown here) which them will result in some sort of command for an engine.  It would be run, and then I want to perceive the tension and the period at a time later and do the same thing.

  (1.) I'm a little confused on what the meter of the READ function is back because it's a table.  What is a picture of?  I thought that it was up to the value of the individual periods between rising edges.  The output of the counter 1 DBL d's a table. How many elements in this table, and what determines the size of this table?  Are the elements of the array the individual delays between the edges?  How many values are stored in the array by executing?   We take the AVERAGE of the last 15 items, but do not know if we are throwing some of the data or what.  How to understand the composition of this painting?  How can I change the composition of this painting?  Is it possible to measure only one period at a time, for example the time between TWO edges?

  2.) Will this WHILE loop execute as it gathers tension and a "period table ' (remains to be understood by me) by TIME running in a loop?  In particular, we want that the value of the tension associated with the value of the AVERAGE of the period "array", so we can use two data items to create orders of next control every time that the two values are reported.  The structure for the delivery of vi will be attached data in pairs like this?  I understand that one of the READING functions run not before the other function of READING in the WHILE loop.  I want that the period "means" and "strain (Volt) collected at the same pace. This vi will he?

  Thank you

  Dave

  Hi David,

  I suggest including the DAQmx Start Task function. If it does not start before the loop, it starts the loop and work very well, but it is not as fast and efficient. In the model of task status, task wiill go to run the checked each iteration of the loop and then back the time checked running when it restarts.

  The status of the task model: http://zone.ni.com/reference/en-XX/help/370466V-01/mxcncpts/taskstatemodel/

  Kind regards

  Jason D

  Technical sales engineer

  National Instruments

• problems of operation of two while loops in a VI

  Hi forum,

  I am developing a project for the acquisition of data continuously for two types of signals (voltage and temperature), each consisting of 20 channels. The sampling frequency is different so I used two call loops of different period to take account of the sampling frequency. It is within the VI that is deployed to the target device. On the host VI, I have two loops while put each containing a VI write_to_measurement express so I can connect the data to two different filepaths. However when I run the program, that a signal is registered correctly while the signal remains would have only one row of data. Looks like one of the while loop is only on the iteration while the other is running smoothly. This is an example of the famine of memory? How can I solve this problem! Any help greatly appreciated! Thank you!

  Vincent

  What asked Fan Ravens is why do you use static variable to stop the loop?  You do something remotely?  Simply use a local variable in your second while loop to stop him.  You need to change the action of the button stop, but that would be the way to do it.  Stop buttons are perfect for debugging and development, but generally I will use one other mechanism to stop the program runs outside the environment of LV.

• Subvi with while loop + event structure works is not in multi tab VI

  Hi all

  I'm developing an interface for the control of a prober using Labview 2012, and I'm stuck with a question.

  First I provide you with a simplified version of my VI control interface and the sub - VI used to generate and manage the mappings of wafer.

  The VI is composed of several tabs: Prober initialization, manipulation of Wafer, Wafer map, status, error.

  The sub - VI can:

  1 / initialize the grid to display the map (Subvi Init grid not provided here)

  2 / coordinates XY for import a txt file (Subvi Wafer map Import)

  3 / view contact information and the index of the sector under the cursor

  4 / and what position die is double clicked and the Boolean 'Edit Wafer map' is true, then the user can change the State (color) of the matrix between die on platelets and selected Die

  My question:

  If I use the sub - VI by itself, it works fine. However, when I use it as a Subvi in the 'Wafer map' tab, the plan does not rise and I can use any features incorporated into the Subvi.

  I suspect that the while loop + structure of the event of sub - VI the bottleneck here.

  However I do not know which way to go, that's why I'd be happy to have some advice and help here.

  Thank you.

  Florian

  The question arises because your hand loop 'for' cycles of 33 times.  In the loop of 32, appears your Subvi and execution is passed to your Subvi.  During this time your main VI expected Subvi in the end, she never does.  You could spend your Subvi out of the main loop of the program and run in a separate process, in order to pass data using queues, but you have to find a way to close the Subvi (i.e. a queue).  By moving the Subvi on the main process, it is independent and you can do what you want to do with the events and others.

• Can not on the button while loop

  Hi all... hoping to get a few design tips as I am very, very new to LabVIEW. I got a project that someone else had started and I've encountered a problem that I don't know how to solve.

  I'm using LabVIEW version 8.0.1 and I think my problem has to do with the help of DAQmx in a while loop. In "Working.vi" (including the Sub - VI 'Temp data to CSV.vi'), I copied - and stuck the while loop in a vacuum VI for testing. In this VI, with nothing else, it works - slowly, but it works.

  In the real VI, I can see the data of temperature updated every 4 seconds, so I know that the program is not frozen or something like that. However, by pressing the button "Return to main Menu" does nothing - the image of the button does not show that it is to be depressed, regardless of how many times you click or click and hold the button. I've attached a screenshot of the while loop inside the real VI; I prefer not to fix the real VI (especially because it contains references to many of the Subvi, and it is not currently contained within a LAW degree).

  I'm this coding the wrong way? I have the feeling that it might be caused by my settings DAQmx (continuous samples, 2 samples to read, 250 mHz). The very low rate would be the cause? Is there a better way to have readings of temperature taken every 4 seconds (approximately)?

  You have your case of event the value "lock the front panel" until full?  If so, then no other presses the button will be recognized until the ongoing case event complete.

  It is never a good idea to have a code in an event business that takes a long time to run.  It will make your UI seems to lag or even functional.  Any time I see someone with a while loop inside a case of the event, I'm afraid.  (By the way, I am also concerned all nodes comments hovering over the structure of your event?  What are doing?  Why some operate on the default data?)

  In general, events should take is no longer running then what ordinary person could be expected until they feel like the user interface is delayed.  Perhaps at the top of 1-2 seconds.  You should look at a model of design of producer/consumer with events.  The structure of your event should respond to UI events, then pass orders by a queue path to the part of your program that does the real work.

• While loop within a while loop

  Just a general question, is a timed, while that while loop the loop inside of a timed bad design practice?

  Any feed back on why it shouldn't be done is appreciated.

  mhaque

  Yes, it's very bad design.

  The outer timed loop cannot complete its iteration unless the timed inner loop ends. This means that its target of time cannot be carried out unless it is guaranteed to be much longer than the total time of the execution of the inner loop. Too late!

  What are you actually trying to do with all this?

• [begineer] reboot a 'while' loop reading the serial port

  Hello! I read some data from a COM port. I want to read my like this "%d S. the unit will send data continuously and depending on when I push the button run in labview, it can start to read data from the middle (%d is a four-digit number). as: 23 S 15'

  "whenever the first character of my data is not of", I need to restart playback. I read the data in a while loop. so I need to stop the while loop. From what I found on the internet, I used a case, another while loop and shift registers.

  but in some way I'm stuck inside the while loop. My VI is attached. Thanks in advance and sorry if my code is a mess!

  PS: what should I do if the bytes I get to the port is variable? use bytes to the port?

  The device sends a character at the end of the line at the end of each message?  You are currently Setup to do this by activating the stop character (currently set to end of line/10/0xA).  If this is true, then simply set the bytes to be read on the VISA to read something rediculously high.  It will stop playback when it finds this termination character.  From there, you just have to check for the correct format.  If this isn't the right format, ignore him.  Otherwise make your recording.

  I managed to clean up your code a bit on this basis.

• Update an indicator of in while loop with event driven programs

  I'm trying to update a chart shared by several events within a Structure of the event. I would like a change in value of a button (NOPE or OK buttons in the attached example images) causes the structure of the event causes a switch between the various outputs for the chart. In the example attached, clicking the OK button will send the graph random matrices, while clicking on the button NOPE will send constant tables to the curve.

  As the process within the structure of the event is underway, I use a while loop within each of the different events in the event Structure. So there is a structure of the event, and each event have while loops in them which should update the chart outside the structure of the event (see attached images).

  This does not update the graph, the graph remains static instead, why is this? How can I configure it to work as I described above?

  In my view, a question is: How can I use the same stop button in both inside while loops. In the example images, I have two that are different, one for each of the different events.

  Thank you!

  
  

• How to set up the execution in a way independent while loops?

  Hello

  I hope someone here can help point me in the right direction for that.  My system at this stage is still quite simple, I just data collection of 2 resistance probe and a pressure sensor, their output in the Panel before and sometimes to write.  I have put architecture in place to call parallel loops running at the frequency I would ideally like to do.  that is, I want the RTD to update every seconds and the pressure transducer for updating chaque.5s, I want to write to the file at a rate defined by the user and I want the Panel before updating a half second (correspondence with the pressure transducer).

  Now, in the structure, I wrote, it should run all the while loop once before it can restart the sequence.  Technically, the code works, but it takes ~1.5s to the RTD to collect and update and so the whole VI takes ~1.5s to complete.

  I don't care if the RTD is slow to update, but as I use the sensor as a gauge of the cell pressure I need to know at a high frequency that the pressure is in the cell, and I don't want to wait 2 seconds for the information.

  I know I'm starting to get into a much more advanced architecture for this and ive spent the last googler 6 hours trying to find a procedure for how it works but I can't figure out a way to have the whiles stop waiting for RTD loop finish.  I guess that this is to divide the VI in several screws and construction of a library, but the resources I could find about it were not very useful for a beginner like me.  If someone could point me in the right direction on where I should look then that would be great!

  Thank you

  Zach

  Zach,

  Because you created the tasks of data acquisition elsewhere, we do not understand how you have set up. Continuously, starting and stopping tasks may be slower than setting up of a permanent task and let it run.

  You have not indicated that you use the DAQ hardware.  It is often better to leave in the DAQ hardware clock set ignition rather than rely on software distribution. The pressure loop reads 1000 samples at a time and calculates their.  If you're not sampling at 2000 s/s or faster, the loop ends late due to waiting for data.  In two loops DAQ, you do not use the calendar information.  Acquire the data in tables rather than waveforms.

  The Dequeue functions in the loop at the bottom have no wait times for this loop will not iterate until all three queues have data. As the pressure loop runs faster than the loop of RTD, the queue of pressure slowly fills.

  The upper and lower loops are vying for the data.  The preview queue item does not delete data from the queue, but the functions of the Dequeue elements in the loop of the low fact.  If data is deleted form the queue before the upper loop resembles it, it will never be saved. With your installation there is no way to ensure that you get all the data or that you do not read and record the same data more than once.

  You don't have anything set up to stop one of the loops.  You use the Cancel button to stop your VI?  If Yes, STOP! Other aprticpant on the Forums said: "using the button abandon to stop a VI is similar to the use of a tree to stop a car.»  It works, but can have unintended consequences. "Things like closing of files, freeing up the queues, by closing the task of acquiring data, and other things can occur when the program is interrupted.  You do not shut down your computer by pulling the plug.  Stop your program also neatly.

  Ok.  I have highlighted some of the things that can keep your program to run as desired.  What can you do about them?

  1. you probably don't need call loops.  Normal so the loop should be good enough.

  2 put a stop button on the front panel. Put the terminal in loops (bottom) and connect it to a function to send a Notification and the status of the Terminal loop (stop sign).  Put wait Notification functions in each of the other loops.  Put a period shorter than the time loop minimum on all of them if the lops can work.

  3. see the comments above regarding the DAQ bed material.

  4 use the Dequeue timeouts to adjust the pitch of the loop the loop where the data is used.  Also make sure that all data is removed.  You need to think about your time together and what are the bottlenecks.  Except if you expect this system to grow to much larger dat sets, I probably acquire ALL data (pressure and RTD) at the same rate and reduce the displayed amount by the average like you do for pressure data now.  If you want different final data rates, just average different amounts of data.

  5. it might be useful to learn how to work the State machines.  Display, averaged and recorded files could be managed in a loop by a simple state machine while allowing for more flexibility in the calendar.

  6. Another good reason to consider a state machine is that initialization and shutdown processes can easily be handled in the corresponding States. At this point you do nothing with errors. A state machine would enable you to handle errors (for example, the cancellation of the selection of the user files) without stopping the program.

  Lynn

• How to do while loop that runs and re - index reset continually

  Hello

  I'm trying to send and read data through the serial port. I'll send separate strings that are stored in a table and the serial port read a value that is returned from my instrument for each string that is sent to it. The table is indexed by the 'i' in the while loop. My problem is, the while loop runs until it reaches the maximum array index + 1, then stop. I would like to have the index restart to zero once it reaches the maximum of 'i' - value, then it returns the values of my table again. It is essentially a program to monitor for an instrument, and I need to continually update the variables in the monitor. I'm new to Labview but is really cool! If someone would be kind enough to help, I would really appreciate it.

  Thank you

  Mike

  Anil Reddy wrote:

  What about using another loop

  Nested loops...

  Please do not do this.

  A Quotient function and the rest is all you need. Entry is equal to the size of the array.

  

• do not shutdown of while loop

  Hello

  I'm LabVIEW and motion controller software OR hardware PCI-7332/UMI-7774 and control a stepper motor.

  My question is:

  When flipping enc = 5 whereas the loop stops

  but with the rest of the value of 20 to 500.

  Why isn't rest zero.

  When the indicator test installation is checked

  the while loop does not stop.

  Please see the attached code.

  Thank you

  The rest would have to do with what happens inside the Subvi, which was not included. The output value of is not stop to an exact multiple of 4095. The question is why that is the case.

  Mike...

• VI is paused and while loop has highlighted

  I'm in parallel while loops and for some reason when it should start to run loops, it pauses for the VI and highlights one loops. It was not last week when I ran it so I don't know what is the issue. I've included a screenshot of the beginning of the code, the loop that is highlighted is the down right. Also, what is the red dot on the wire in error right after the structure of sequence?

  Thank you

  lvuser333 wrote:

  I'm in parallel while loops and for some reason when it should start to run loops, it pauses for the VI and highlights one loops. It was not last week when I ran it so I don't know what is the issue. I've included a screenshot of the beginning of the code, the loop that is highlighted is the down right. Also, what is the red dot on the wire in error right after the structure of sequence?

  Thank you

  Someone snuck into a breakpoint on you.  The red dot is the stopping point, and that's why your VI made a break.