Non-retriggerable one shot utilizing While Loop

Hello,
I would like to generate a non-retriggerable pulse (long - 5 to 10 minutes) from the rising edge of an asynchronous pulse (short - 1/2 to 1 sec). I do not want the short pulse to retrigger the long one. In fact if this happens I would like to flag it as an error.
I am running LabVIEW 6i Real Time on an PXI-8170 controller with a 6071E DAQ board.
I have a hardware timed 1ms While Loop that I would like to use for the timing. Can this be done without using Global or Local Variables? I have been trying to figure out a way to use shift resgistars to avoid the possibility of the "i" terminal rolling over.
Any ideas, comments or suggestions much appreciated.
Attached is my vi.
Thanks
Hans
Attachments:
DCPS_PROTO.vi ‏225 KB

Hans,
Unfortunately I wasn't able to open your VI but I will give you my suggestion anyway.
As you probably have noticed, the counters are not capable of generating that long pulses, so that leaves you with the options of digital or analog output.
The digital I/O on the E series devices doesn't support any handshaking, so you would have to generate a DAQ event from your trigger and then write to the port.
You can trigger the analog output operation with a digital pulse and reset the output value when your timer loop reaches a certain value. You don't necessarily need to use a local variable to pass this information out of the loop (assuming you want to keep the loop iterating). The LabVIEW occurrence is a nice way to implement it (under Advanced -> Synch
ronization palette).
It's going to take almost 25 days for your iteration terminal to roll over at 1 ms iteration. When it does the output from the terminal stays at the maximum value, 2147483647. If this is a problem you can check for the terminal value and when you reach start counting the following iterations using a shift register.
Kai

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write-host "This script sets up DATABASE Staging"
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$mysqlConnection.Open()
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$mysqlConnection.Close()
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$mysqlConnection.Open()
$Result = $Command.ExecuteNonQuery()
$mysqlConnection.Close()
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[System.Data.SqlClient.SqlCommand]$Command) #the command to execute (name of stored procedure)
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$Command.Connection = $sqlConnection
$sqlConnection.Open()
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cd /d/DATABASE3/code_stg
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param}($DATABASE0980453.pkg,"d/DATABASE3/code_stg")
# create destination if it's not there ...
#mkdir $destination -force -erroraction SilentlyContinue
foreach($original in ls $source -recurse) {
$result = $original.FullName.Replace($source,$destination)
while(test-path $result -type leaf){ $result = [IO.Path]::ChangeExtension($result,"copy$([IO.Path]::GetExtension($result))") }
if($original.PSIsContainer) {
# mkdir $result -ErrorAction SilentlyContinue
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copy $original.FullName -destination $result
While($ElementDistro -match $DATABASE4 ) {
function Execute-MySqlcommand {param( [string]$Server, #the host of the SQL server
[string]$DATABASE4, #the name of the database
[System.Data.MySqlclient.MySqlcommand]$Command) #the command to execute (name of stored command)
$mysqlConnection = new-object System.Data.MySqlclient.MySqlConnection
$MySqlConnection.ConnectionString = "DROP_VIEW DATABASE.BTXADDR;DROP_VIEW DATABASE.BTXSUPB;CREATE_VIEW DATABASE.BTXADDR FOR DATABASE4.DATABASE42.BTXADDR;CREATE_VIEW DATABASE.BTXSUPB FOR DATABASE4.DATABASE4S3.BTXSUPB"
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# mkdir $result -ErrorAction SilentlyContinue
# } else {
copy $original.FullName -destination $result
cd /d/DATABASE4/code_st
install ../DATABASE0980453.pkg
While($ElementDistro -match $ALL ){
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[string]$DATABASE1,$DATABASE2,$DATABASE3,$DATABASE4, #the name of the database
[System.Data.SqlClient.SqlCommand]$Command) #the command to execute (name of stored procedure)
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write-host "You must type DATABASE1 or DATABASE2 or DATABASE3 or DATABASE4 or ALL"
write-host "you typed $ElementDistro"
write-host "set location you want to run staging"
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OK, so you've got a reasonable input loop early on:
write-host "This script sets up DATABASE Staging"
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write-host "This script sets up DATABASE Staging"
$ProductionDistro = Read-Host -Prompt "Which production do you `enter code here`want to run?(TC/MonsterLock/Cyc)"
I've only added two things to that code: a ^ and $ at the beginning and end of your regex pattern. As originally written, it would have successfully matched any string containing TC, MonsterLock or Cyc (such as "bogusTCwhatever", etc).
Now, instead of a bunch of extra While loops based on $ProductionDistro, what you need is some conditionals (either a Switch statement, or some If/ElseIf). For example:
switch ($ProductionDistro)
'TC'
# Do TC Stuff
break
'MonsterLock'
# Do MonsterLock Stuff
break
'Cyc'
# Do Cyc stuff
break

I currently have one input but need to run two loops. I cannot get the two while loops to run so that they both pick up the same data, they are both picking up alternate samples. How can I get them to both pick up all of the values?

The system I am trying to create calculates a number of values based on an input. I need to make the calculations and display the values for an entire production run and for each hour. The only way I know to do this is to create two while loops, one looking at all the values that are received and one looking only at the values for hour long periods.
Any help would be great.
Thanks
RossH

Why do you think that you have to have two loops to accomplish this task? Why not use one loop and accumulate the same data into two data sets based on the two sets of criteria?

How do I make one while loop that runs 1 piece of data at a time?

I have a question about a while loop. Currently, I have 4 or 5 dynamic data lines that I would like to run through a while loop that will tell me if the data is within a certain range or not. However, the ranges are different for each piece of data, and I dont know how to do each one separately. Do I have to make 5 different while loops? Thanks!

pg22aw wrote:
I have a question about a while loop. Currently, I have 4 or 5 dynamic data lines that I would like to run through a while loop that will tell me if the data is within a certain range or not. However, the ranges are different for each piece of data, and I dont know how to do each one separately. Do I have to make 5 different while loops? Thanks!
Do you want to compare the value with a defined value and also the ranges for the 5 data is different?. What are you doing in the while loop. If the data is in an array of dynamic data you can seperate the amplitude value and check the whole array of value with the ranges that is also build same as the data theh you will get the output as a boolean array.
The best solution is the one you find it by yourself

What is the best way to pass a controlling signal out of a sub vi or more than one layer of for loop, while the sub vi or for loops are still running?

I have a vi that runs through two for loops and a while loop, then after a certain number of iterations on the inner while loop it is supposed to pass a trigger to a case stucture to start measurement. I have tried using a local variable attached to a boolean control which in turn is attached to the true case of the case structure involving the measurement sub vi. What is happening is that the boolean control will light on the front panel at the correct # of iterations in the while loop, as if true, but the measurement is not taken, and the boolean control never goes back to false. It remains lit. Am I u
sing the local variable incorrectly? If so, where am I going wrong.
Attachments:
GL_Flicker.vi ‏118 KB
Take_Measurements.vi ‏147 KB

Hello planar,
There are multiple ways to pass control information between loops and VIs and each one has its place. For simple VIs like your example, a local variable will be fine.
The main reason the subVI is not running is that the case structure is not continuously polling the Boolean control. This is because the case structure is not inside a loop and as such will only read the Boolean value once and execute once. Encasing the case structure and control inside the while loop should solve the issue of the subVI not running.
You may find the following links of help in creating more robust and advanced VI architectures.
Application Design Patter
ns: Master/Slave
LabVIEW Application Design Patterns
Keep up to date on the latest PXI news at twitter.com/pxi

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Attachments:
Capture_and_Save_as_AVI.vi ‏177 KB

Thanks. I suspected as much. In any event, I can't seem to find a good configuration of while loops and case structures which will produce the desired results. I want to start acquiring images and allow the user to choose to start recording at any time he desires. This issue is further complicated by the fact that the status of the "Start recording" must be checked at all times, but only initialized once, while the AVI Write Frame depends on that first initialization step but must be looped continuously aferwards in order to 'keep up' with the images being acquired. In the newly attached example, I placed the case structure inside the image acquisition while loop and the avi write frame inside a while loop inside of that case structure. unfortunately,
labview decides to stay inside the avi write frame while loop after entering, instead of returning to the image acquisition while loop. i can't place the avi write frame inside the general image acquisition while loop because then labview will think i want to initialize the avi write frame right away and will return an error when avi write frame isn't provided with an avi refnum. Ideas?
Attachments:
Capture_and_Save_as_AVI.vi ‏174 KB

Multiple While Loops Write to One File

Hello,
I have three different instruments from which I am sampling, each at a
different sampling rate. Each instrument is being sampled in its
own While loop. How do I write all the samples I collect to a
single text file? I would like something in the following format:
[Timestamp] [Instrument 1's First Sample] [Instrument 2's First Sample] [Instrument 3's First Sample]
[Timestamp] [Instrument 1's Second Sample] [Instrument 2's Second Sample] [Instrument 3's Second Sample]
...and so on..
Thank you,
Olyvia

ofro wrote:
I have three different instruments from which I am sampling, each at a different sampling rate. Each instrument is being sampled in its own While loop. How do I write all the samples I collect to a single text file? I would like something in the following format:
[Timestamp] [Instrument 1's First Sample] [Instrument 2's First Sample] [Instrument 3's First Sample]
[Timestamp] [Instrument 1's Second Sample] [Instrument 2's Second Sample] [Instrument 3's Second Sample]
...and so on..
This seems like a flawed project.
If each loop samples at a different rate, the samples will arrive at different times. Typically there won't be a single timestamp for all three samples. Can you explain what you actually want to write to the file from each loop?
Do you want to write to the file incrementally inside each loop, or do you want to write everything at once after all loops have finished?
LabVIEW Champion . Do more with less code and in less time .

Iteration non sequencial with While Loop

I've a SubVi in while Loop. Iteration n+1 will execute when Iteration n finish.
Can I execute this SubVi in paralel (no sequencial)?
In Spanish:
Tengo una SubVi dentro de un bucle while. Pero este bucle actúa de forma secuencial. No se cargará la iteración n+1 hasta que la n acabe.
¿Cómo puedo hacer para que se ejecuten las iteraciones de forma no secuencial? Es decir, que no haya que espera a que acabe una para que se ejecute la siguiente.

Hello,
it is not possible. The while loop works as follows: 1) execute the code inside 2) check the ternimation condition 3) depending on that, continues with the following iteration or exit from the while loop. So, it is not possible what you are asking for.
Maybe you have to use two while loops.
Regards
rusC

Is it possible to have one while loop in another while loop

Is it?

Well, actually there are several possibilities:
1. You right click the orange square where the double value gets out of the loop and select "enable indexing". This results in an array of all values you get while this inner loop is running.
2. You add a shift register to the outermost loop and use the "build array" function after the inner while loop. This results in an array of the last value after the inner while loop has stopped.
3. You combine both ways described above. Then you get a 2D-array.
You can see this in the attached vi. In every case you have to be aware of what happens with the memory. In case 2 and 3 the array grows steadily. This could leed to problems, so you have to take care to empty it, if possible.
Now it depends on what kind of data you need.
Using LV8.0
Don't be afraid to rate a good answer...
Attachments:
BuildArray.vi ‏16 KB

Stuck inside an infinite While Loop :-/

Hi all,
When I write this program using the top-down structural method, it runs fine but when I use the call method inside the while loop, it doesn't test the "if" condition. It becomes a never-ending loop. :-/
import java.util.Random;
public class WhileLoop {
      public static void main(String[] args) {
        int random1;
        Random die1 = new Random();
        random1 = die1.nextInt(6) + 1;
        WhileLoop r = new WhileLoop();
        while (random1 != 5) {
          if (random1 != 5) {
           r.doRandom();
          if (random1 == 5) {
            System.out.println("you win! ");
         int random1;
      public void doRandom() {
         Random die1 = new Random();
         random1 = die1.nextInt(6) + 1;
         System.out.println("random1 = " + random1);
}If I replace the line " r.doRandom(); " with " random1 = die1.nextInt(6) + 1; System.out.println("random1 = " + random1); " the program will check the "if" condition and stops when it finds the number 5. What's wrong with my code?
Thanks for your help.

DrLaszloJamf wrote:
{color:#3D2B1F }You have two, unrelated variables that happen to both be named random1.{color}Opps! Must have missed it. Using two unrelated variables with the same name was, unintentional ~ //yea, right (blush). Thanks for pointing it out. :-)
Encephalopathic wrote:
you never change random1 from within the while loop. You think you do, but it's a different random1 that you're changing, a non-static one that is an instance variable.okay~ but does it mean that 'random1' from the method within the while-loop cannot be used for comparison purpose? I tried using a 'return' value from the doRandom method and use that value inside the "if" condition, but it also does not terminate the loop. The only way it's going to work is by using the solution DrLaszlo gave? Is there any other way to do this by using a call method?
Thanks!

Non-retriggerable one shot utilizing While Loop

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