Saving to spreadsheet after stopping a while loop

Hello,
I am writing a program that generates an analog signal, transmit it to Schmitt trigger, then puts out the original signal and the trigger signal into a waveform chart. It then must output a series of data as a spreadsheet file after the loop is stopped.
I've gotten the thing to output a waveform chart and stop it with a button, but I can't output it as a spreadsheet file. What should I do? I've arrayed both sets of output into 1D array, but after pressing STOP it won't do anything. If I stick the save to spreadsheet vi into the while loop, the save prompt triggers, but after only the initial iteration.
The "noisy analog" is a signal generator using a function, which is rendered into a subvi and imported into untitled 1.
Solved!
Go to Solution.
Attachments:
noisy analog.vi ‏9 KB
Untitled 1.vi ‏19 KB

I've passed the array to the outside of the loop, enabled indexing, but again it does nothing. Any ideas? I've also tried linking into a select but it really just refuses to write to spreadsheet.
Attachments:
untitled 1 select link.vi ‏18 KB
untitled 1.vi ‏19 KB

Similar Messages

How to stop a while loop after certain time using Elapsed time vi

how to stop a while loop after certain time using Elapsed time vi.

Hi Frankie,
Just place the Elapsed Time VI inside the WHILE loop, and wire the 'Time Has Elapsed' output to the conditional terminal in the lower right corner (which should be set to 'stop if true' by default).
In the future, please post your LabVIEW questions to the LabVIEW Forum. You have a much better chance of getting your questions answered sooner, and those answers can then help others who are searching the LabVIEW forums. Thanks!
Justin M
National Instruments

How do i stop a while loop

I'm new to labview and I'm having a problem stopping a while loop (running windows XP/2000 with the student edition of labview express 7).
I'm doing a data acquisition program where I'm constantly reading in voltage and comparing it to a set point value, when the input voltage goes above the set point, i want the while loop to stop. How do I do this? I already have an LED going on when the criteria is met, but I'm not sure how to actually stop the loop (i.e. change the iteration value from true to false-i guess). If anyone can please assist me with this I would very much appreciate it.
I've included my program too.
Attachments:
CO_Detection_Monitoring_System_Modified.vi ‏60 KB

Hello Everyone-
I've just posted a message about stopping a while loop and it was answered accurately and quickly- thanks to LV_Pro and PauloM- thanks much- its nice too see that there are many helpful people out there! Unfortunately, I have 2 more questions to ask of the forum.
My application is almost completed- I just need to add an elapsed time counter that will tell me how long it took for my LED to trigger (from my set point-i.e. when from 0:00:00 until when my loop stopped).
Now I've found a perfect elapsed time counter on the NI web site contributed from Mike Hall from Ohmeda Medical- the page is here.... http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=D37E2493DC333076E034080020E74861&p_node=DZ52032&p_source=external
So my first question is, it looks like I can just extend the while loop box in my 'CO detector... .vi' and paste just the code from the 'elapsed time.vi' while loop into my loop and I will be set- but do I need to change my wait until next multiple to be a 1000 too in my program? Probably, but I'm not sure hence the question- or other ideas would appreciated.
My second question is now that my application is complete (after I add the elapsed time above), I need to exactly duplicate this process for 7 other DAQ inputs (i.e. right now I'm using only 1 of 8 analog inputs on the FP-AI110). So should I make my 'CO detector.. .vi' a separate program (I remember reading something about this in one of the posts earlier).
Any help is very appreciated.
Thank you again,
Daniel
Attachments:
CO_Detection_Monitoring_System_Modified.vi ‏60 KB

Code golf: stop two while loops with guaranteed iteration ratio

Proposal
In the vein of the Perl tradition, I'd like to see if there's any interest in solving short programming puzzles in LabVIEW. Anyone can post a problem and define the rules for solving it.
Here's a beginning/intermediate question to whet your "palette".
Description
With one user-action, how would you stop two while loops such that the ratio of their iterations is the always the same? One concrete way to visualize this situation is in taking measurements: two instruments use the same timing source to take measurements, but second divides the clock down so that it is an integer factor slower than the first. For example, if the slower instrument is four times slower, then at the end of the VI, if the slower instrument takes 100 measurements, the faster instrument has taken 400.
Rules
You may only use vi.lib
You cannot include any other subVIs
Your solution must pass for loop1 interval as low as 25 ms
Template (attached in LabVIEW 2009)
If folks are interested in this, then let's figure out how to make future problems better. Please post your suggestions and critiques, but only if you also post a submission ;-)
Solved!
Go to Solution.
Attachments:
Multirate Loop Code Golf.vi ‏11 KB

Norbert_B wrote:
a) You work with an integer factor of speed. While this matches many application areas, there are still cases where the factor has to be floating point (e.g. 2.5). Additionally, the factor might "invert", so the master loop runs slower than the slave (factor 0.5 for instance).
It sounds like you're about to post another code golf question. If you think the problem scope is too small, you're welcome to fashion one to your taste. Thanks for volunteering :-D
Norbert_B wrote:
b) This example does not take into account that the hardware has to be synchronized with more accuracy than the software supplies (PXI?). If hardware synchronization is required, there are two possible ways:
- The factor can be included in the synchronization (using PLL for instance)
- The factor has to be software implemented by data reduction for the task running at the lower pace.
Hrm, maybe puzzles aren't really your thing after all. You are correct: I did not define every constraint that can lead to a provable best closed-form solution, but that does not prevent people from stating their assumptions and forming creative, well-reasoned, and still correct designs. I overlooked this reading of the description and neglected to add a statement that said solvers were free to add their own conditions. I will do so in the fugure :-)
If we choose the first of your suggestions, the VI must still retrieve the data at different rates. You can dedicate a loop for each instrument to decouple any jitter and latency introduced by their connectivity or internal operation; this adds some margin of safety when there is thread and driver contention. You can also implement a single counting loop like altenbach and forego the multiloop complexity.
Norbert_B wrote:
c) You don't state anything about "what happens with the data". Is this time consuming? Does it introduce additional delay in loop iterations? Is it OK to have data loss?
I don't know -- you decide, you disclose, and you solve :-)
In my specific situation, the measurements are time consuming and do add delay (each data "sample" is 5-20 megabytes), none can be lost, and the data must be available for others to analyze later. In addition, the amount of data is saturating the hard disk throughput. If a particular write takes too long, the instrument driver may overwrite a yet unfetched sample, which is unacceptable. I did not add these details to the problem discripton becuase they don't impact the puzzle.
I don't want to burden people with my situation and ask them to solve my problem: I want to encourage them to bring their intuition and experience to a discussion. This is the design process at its heart: understanding why and how constraints affect your decisions. If a person states the additional conditions they've assumed, readers can learn why, and more importantly, when a Notifier might be more desirable than an Occurance or a Queue more robust than a Data Value Reference.
The best NI-published advice for stopping multiple while loops (https://www.google.com/search?q=labview+stop+multiple+while+loops) is laughable (and is the "solution" in my template).
Would you care to re-approach and contribute to this puzzle? I suspect you have a lot to offer :-)

I have a for loop inside of while loop.when i press stop for while loop, i also would like to stop for loop.how can i solve this problem?thanks

i have a for loop inside of while loop.when i press stop for while loop, i also would like to stop for loop.how can i solve this problem?thanks

Hi fais,
Following through with what JB suggested. The steps involved in replacing the inner for loop with a while loop are outlined below.
You can replace the inner for loop with a while by doing the following.
1) Right-click of the for loop and select "Repalce" then navigate to the "while loop".
2) Make sure the tunnels you where indexing on with the for loop are still indexing.
3) Drop an "array size" node on your diagram. Wire the array that determines the number of iterations your for loop executes into this "array size".
4) Wire the output of the array size into the new while loop.
5) Set the condition terminal to "stop if true".
6)Drop an "OR" gate inside the while loop and wire its output to the while loops condition terminal.
7) C
reate a local of the boolean "stop" button, and wire it into one of the inputs of your OR gate. This will allow you to stop the inner loop.
8) Drop a "less than" node inside the inner while loop.
9) Wire your iteration count into the bottom input of the "less than".
10) Wire the count (see step 4 above) into the top input of the less than. This will stop the inner loop when ever the inner loop has processed the last element of your array.
Provided I have not mixed up my tops and bottoms this should accomplish the replacement.
I will let others explain how to takle this task using the "case solution".
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

How to stop a while loop of event structure from a main vi

Hello;
sorry for my english
I have to stop a subvi from my main vi, the subvi contains a while loop and an event structure so I need to stop this loop while directly from my main vi I have tried global variable but it did not work
any help please or example !!!
Solved!
Go to Solution.
Attachments:
stop a while loop and event structure from main vi.png ‏16 KB

IYED wrote:
Hello;
sorry for my english
I have to stop a subvi from my main vi, the subvi contains a while loop and an event structure so I need to stop this loop while directly from my main vi I have tried global variable but it did not work
any help please or example !!!
If this is an example of how your code looks, I'd clean it up before the developer who has to work on it next hits you over the head with his LabVIEW Style Book.
Bill
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.

How to stop a while loop in LabVIEW from a C program

How to stop a while loop in LabVIEW from a C code

hi
I think by creating dll you can stop the while loop from your C program.For that you just create dll (Dynamic Link Library) for the VI which has that while loop.
Anyway can u please explain ur requirement clearly.

Stop multiple while loops in Vision Aquisition

Hi, I want to close multiple while loops with one stop button. I'm using the Vision Acquisition software for recording from multiple cameras and I want to close this recording from all cameras simultaneously. Since I'm knew to LABView I don't know how to do this. I'll include my VI here and maybe someone can help me. Thanks!
Solved!
Go to Solution.
Attachments:
Aquire Images 2 with Cameras.vi ‏410 KB

A local variable should be enough for your implementation. Look at the following article:
Stopping Parallel While Loops in LabVIEW With One Stop Button
Adnan Zafar
Certified LabVIEW Architect
Coleman Technologies

Stopping a while-loop in a sub-vi

Hello,
I want to stop a while loop that runs in a sub-vi. It does not work with a local variable, is there a possibility to implement this without using global variables?
Many thanks !

One way is to use a notifier.
See attached - Uses LV 7.1.Message Edited by NeilR on 05-04-2005 08:10 AM
Attachments:
stop2.zip ‏14 KB

Stopping a while loop with a button in cvi

Hi people,
I am a newbie with CVI but I have used LabView Heaps. The issue I have is I want to be able to use a toggle button or a command button to stop a while loop. I used GetCtrlVal on the toggle before the while loop. I then enter the while loop and then GetCtrlVal at the end to see if the button has been pressed. The issue I have is that once I enter the loop I am unable to press any buttons on the Panel. I would normally have put a delay in the loop but the issue is I am wanting to control a robot in "realtime", thus any delays in the program results in the robot moving further than what I wanted it to. Any ideas? If you have any suggestions that would be much appreciated thank you.

This should be in the CVI group but...
At the tail end of your while loop add a call to function ProcessDrawEvents():
When your program executes in a callback function or in code that does not call RunUserInterface or GetUserEvent, LabWindows/CVI does not update the user interface. Functions that are overly time-consuming can "lock out" user interface updates. To allow LabWindows/CVI to process these updates, call ProcessDrawEvents.

Time not stopping with while loop

Hello,
I've attached my VI. I am having trouble with while loops.
I want to turn on LEDs. The first LED should turn on after 3s. The second LED should turn on after 5s. The third LED will turn on later.
The LEDs turn on based on the following conditions:
Case 0: numeric control > 10 then led_1 off, led_2 off, led_3 off
Case 1: numeric control <= 10 then led_1 on, led_2 on, led_3 on
Case 2: numeric control <=5 then led_3 on
Because of the way I'm delaying time, I have the following problems
Case 1 --> case 2: led_3 doesn't come on right away
Case 2 --> case 1: led_3 doesn't turn off right away
Putting probes in certain areas leads me to believe that these problems are due to the way the time delay is being generated.
Thanks in advance.
EDIT: Looking at it more...it seems to be that when the stop condition is true, the loop runs one more iteration. Is there a way to keep it from running that "one more iteration."
Attachments:
timing.vi ‏15 KB

One of the problems is that your VI is not able to "breathe" because it is sometimes trapped inside inner loops that consume all CPU and step on each others toes. All you need is an single outer loop and a few shift registers.
May of your specifications are still not clear, for example what should happen to LED 1&2 in case #3? Should they remain in the state they are in, or should they turn off, for example.
Here is a simple rewrite that spins the outer loop at a regular rate, has no inner loop, and does not need any local variables or value property nodes. See if it makes sense. Also note that your code can be simplified dramatically by using arrays. Since the stop button is read with each of the regular interations, we don't need to worry about sequencing.
Most likely you need to do a few simple modofications, because your specs are not clear.
LabVIEW Champion . Do more with less code and in less time .
Attachments:
timingMODCA.vi ‏15 KB

Stopping a while loop using the time difference of two tick counts

Hi Guys,
I'm currently writing a code which test how long does it take for a formula node to perform its operation. The program uses a while loop to perform the calculation, and the program stops after calculating when tick count has reached 10 seconds. The program then displays the number of iterations it does in 10 seconds.
So initially I created 2 frames of sequence structure. In my first frame I have my initial tick count, and in my second frame I have my final tick count and the while loop. I used the subtract function and divide the output by 1000 to get the time difference. Then using the comparison function, I set if output > 10 then the program should stop, to do this I linked the output of the comparison function to the stop button inside the while loop.
However, when I tried to run the code, the program just didn't run. Hence I created a similar program which puts the last tick count in new frame sequence. When I ran this code, the program never stopped.
Do you guys have any idea what went wrong with my codes.
Thank you!
Erry
Solved!
Go to Solution.
Attachments:
1. Tick Count.vi ‏27 KB
tickcoun2.vi ‏27 KB

Dataflow!
In both VI's the stop terminal of the while loop is controlled by a boolean whose source is ouside of the while loop. So that loop will either run once, or run forever, depending on the value of the boolean that is calculated before the loop starts and shows up at the tunnel going into the loop.
I would recommend looking at the online LabVIEW tutorials
LabVIEW Introduction Course - Three Hours
LabVIEW Introduction Course - Six Hours

Stop dependant while loops with 1 button

Hi,
I am developing a utility that allows a user to configure up to 2 devices (both use same driver with a different board number), click initialize, which then brings up a file dialog and displays arrays for the data to be collected and some error messages for each measurement. The user then clicks the Start/Stop button to begin collecting and logging data. Currently i have a Wait(ms) block to allow the user to set often the measurement should be made. Currently the Start/Stop button allows collection to be started, paused, and started again. My problem is trying to have a master stop button that should stop all loops immediately when it is pressed.
I tried using a global variable for the stop button, but the measurement and logging while loop doesnt stop until after the wait(ms) block times out. Can anyone give suggestions. If i need to restructure the VI into different loops, I can do that. I just want to understand the right way to program something like this.
The VIs are attached. I removed the device specific measurement VI so that anyone can open the vis and run them to see how it works.
Attachments:
2Devices_withoutMeasurementVI.vi ‏112 KB
BuildOutput.vi ‏27 KB
stopGlobal.vi ‏5 KB

Ok. I had a chance to take a look at your code and I think you don't quite understand the concept of "dataflow". Let me see if I can help.
First of all...when I refer to your upper structure, I am referring to the first while loop, sequence structure, and subsequent while loops. When I refer to your lower structure, I am referring to the while loop containing the event structure. Just so we get our terminology straight.
I believe that you are under the illusion that your upper structure contains three parallel while loops. It does not. It contains three SERIAL while loops. There is dataflow dependency between the while loops. The sequence structure requires data that is not available until the first while loop has finished executing, so the sequence structure cannot start executing until the first while loop has terminated.
The second while loop requires inputs from the first frame of the sequence structure (which, by the way, you don't need and should get rid of...the sequence structure, I mean), so it cannot start executing until the first frame of the sequence structure has terminated. The third while loop requires inputs from the second while loop...so, again, the third while loop cannot run until the second while loop has finished executing.
Now, for your stop button. You have that global stopping all three loops. So here's what is happening in your program:
Your program starts. The first while loop executes in parallel with the loop which contains the event structure.
At some point you press the "stop" button. Both the first while loop and the loop containing the event structure finish executing.
The first frame of your sequence structure executes.
The second frame of your sequence structure executes. The second while loop reads the "stop" value from the global, so it executes once and then finishes.
The third while loop starts executing. Again, the loop reads the "stop" value from the global, so it executes once and then finishes.
Then your program terminates.
You need to restructure your program, because right now it doesn't make any sense at all. Your block diagram would benefit from some serious tidying up as well, your wiring is a mess. I suggest you look into a state machine architecture for this program.

While loop takes control of everything, i.e. stop a while loop

Hi everybody,
I have a problem with a while loop, which I don't manage to stop as it
takes control of everything.
So, the problem is the following.
I wrote a vi to control an Optical Spectrum Analyzer and I need it to
scan a trace every Ta seconds. The scan must start when the user
presses the button "Start datalogging!" and must stop when the user
presses the button "Stop datalogging!" (this button is configured as
"swith after pression").
The problem is, anyway, that after starting the datalogging operation,
the user interface becomes kinda inaccessible, the mouse pointer
assumes the "hand format" and you can't push any button (actually you
can't move the scroll bars either, nothing), but the one to abort the
execution, making thus impossible to stop the acquisition or any other
operation.
It seems like the operation of collecting data is so "CPU consuming"
that LABVIEW can't "listen" to any input.
The LABVIEW version I am using is the 8.5.1.
I hope somebody can help me solving this problem.
Thanks a lot,
Gianluca

Hi,
You may want to try the following:
1) create a while loop, leave the conditional terminal open for now
2) inside the while loop, create an event structure (on the same palette as 'while'- and 'for' loops)
3) Add an event by right-cllicking the top textfield of the event structure, choose your startbutton-control in the left menu, and in the right menu scroll down to 'value change'. Before exiting this menu make sure to uncheck the checkbox for 'lock front panel'
4 inside the eventstructure for your start-button, put your start-button control - it needs to be read by the program to work properly (unless you chose another form of mechanical action). Wire it through the wall of the event-structure and to the conditional terminal, insert a boolean 'not' to reverse the polarity.
5) Add a constant to the 'timeout' value on the left upper corner (outside the event structure),give it the value 100 [ms]
6) select the timeout page in the structure (it was there by default as the first page)
7) insert your scanning program in here, it will iterate (start) every 100ms (due to your constant in step 5)
8) add another event, select your stop button control in the left menu, select 'value change' in the right menu
9) Place your stop-button control inside the new page in the event-structure, wire a line through the frame down to the conditional terminal
10) you are done
Brgds
T

How to use Boolean values from 2 different sources to stop a while loop?

I am working on a program for homework that states E5.4) Using a single Whil eLoop, construct a VI that executes a loop N times or until the user presses a stop button. Be sure to include the Time Delay Exress Vi so the user has time to press the stop botton.
I am doing this right now but it seems as though I can only connect one thing to the stop sign on th while loop. It won't let me connect a comparision of N and the iterations as well as the stop button to the stop sign on the while loop. So how would I be able to structure it so that it stops if it receives a true Boolean value from either of the 2 sources (whichever comes first)?
Basically, I cannot wire the output of the comparison of N and iterations as well as the stop button to the stop button on the whlie loop to end it. Is there a solution?
Thanks!
Solved!
Go to Solution.

Rajster16 wrote:
Using a single Whil eLoop, construct a VI that executes a loop N times or until the user presses a stop button.
Look in the boolean palette for something similar to the word hightlighted in red above.
LabVIEW Champion . Do more with less code and in less time .

Saving to spreadsheet after stopping a while loop

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