Case structure is restarting at 120? should go to 167

My case structure is restarting at 0 when it gets to case 120 instead of continuing until 167? also, how can I get my vi to execute a certain case for x amount of time, i tried the wait vi but it just wait to execute instead of executing until time is up. I would appreciate any help, thanks.
Here is my prog.
Attachments:
version22.vi ‏1329 KB

If you go to case 120 you'll notice that you did not wire the ring to the output tunnel. Thus it will get reset to zero.
(Just right-click on the output tunnel and deselect "use defaut if unwired". Now click on the broken run arrow and search for the error about the missing tunnel assignment and double-click the error. It will get you to the error).
Your programming style is unbelievable tedious. Why don't you follow our advice and streamline your code. Is there anything in my last example that you don't understand?
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Similar Messages

How to make wave graph restart when the condition of case structure is changed?

Exp: Condition of case structure a<b ( a: control, b: constant). A wavegraph puts inside a while loop , in True condition (a<b). How can I make the wave graph restart if a is changed?

Aren't you confusin waveform graph and waveform chart ? If this is the case, you can clear a chart using the History data property node, fed with an empty array.
Message Edité par chilly charly le 11-08-2007 01:57 PM
Chilly Charly (aka CC)
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Attachments:
Example_BD.png ‏1 KB

Case structure not going through all cases before restarting

I have a case structure and it is not going throught the entire list of cases, I cannot figure out the problem. Any help would be greatly appreciated. I have attached my VI:
Attachments:
42sampleWorkingCodeNI.vi ‏974 KB

In your case labeled "exhauset 24", you reset the state back to "valve 2 open".
Your program is way (way!!) too convoluted to do any serious code maintenance. Properly written, the same functionality can be achieved wich much less code. 90% of your code is duplicate. Why don't you use arrays?
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Resetting a Case structure

I am writing a VI that reads in a signal to a comparator and sends the
output
to a
case structure.
The ides behind the project is EMG (monitoring muscle active/inactive
times).
The case structure is as follows:
If 1: count up and if count reaches 10 then green LED on (represents muscle
active)
If 0: count up and if count reaches 10 then red LED on (represents muscle
inactive
and should be exercised.)
My question is how could I reset the case structure to start again: i.e, If
Case=0
and the inactive time reaches 10 and RED LED comes on, I want this to then
turn
off
and put the count back to 0 if it switches to Case=1.
(The idea is that this RED LED is representing a Vibrate motor (which I
will
output
to using DAQ) . The motor will switch on as the RED LED does to indicate to
a
user
muscle should be exercised but I do not want the motor to be on constant, I
need it
to turn off when the muscle is exercised and then restart the count again)
I probably haven't explained this very well but I have attached my VI.
Any help would be appreciated
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PinkLady4128 wrote:
The case structure is as follows:
If 1: count up and if count reaches 10 then green LED on (represents muscle
active)
If 0: count up and if count reaches 10 then red LED on (represents muscle
inactive and should be exercised.)
What is the count interval? How is the count increment triggered (time ie: every second?)
My question is how could I reset the case structure to start again: i.e, If
Case=0 and the inactive time reaches 10 and RED LED comes on, I want this to then
turn off and put the count back to 0 if it switches to Case=1.
Do you want the reset to occur automatically and restart? Do you want someone to notice the RED LED? If it resets, do you want to start again but keep the RED LED on which also indicates that the motor is running?
(The idea is that this RED LED is representing a Vibrate motor (which I
will output to using DAQ). The motor will switch on as the RED LED does to indicate to
a user muscle should be exercised but I do not want the motor to be on constant, I
need it to turn off when the muscle is exercised and then restart the count again)
So while it is counting, if there is muscle
movement detected, do you want the motor to stop and the RED LED to turn
off?
I probably haven't explained this very well but I have attached my VI.
You forgot to attach your VI

Can I put a READ function in a TRUE/FALSE case structure?

Hi,
I have a vi that operates as controller for a mechanical system of motors. There are several sensors of various types, that provide input to the vi, including encoders, whose period is being measured. The attached vi is the encoder period measuring part. It measures 15 periods and tells me the average of the 15 with each loop iteration.
In my application, the encoder period measurement is not needed unless the vi knows that ALL THE OTHER sensors in the hardware configuration are measuring values within the desired range. For example, Sensors A, B and C should all measure between 5-10. If they are all showing values between 5-10, then, we want the encoder value to read and display. If only one of the sensors, say A, is measuring 12, then, we don't want the period value to READ or be subsequently processed. So, it is easy to set up the sensors A, B, C, to give a TRUE or FALSE based on whether they are within range or not, and if all 3 are TRUE, then, that value can easily be passed to the case structure that holds my READ function for the period. Is this a good way to do this? The goal is to eliminate unnecessary execution time that the period READ function would consume, as well as all subsequent calculations that are performed on the period value collected. The period data is of no use if any one of the other sensors is not in the correct range.
If any one of the other sensors is out of range, we want to skip the encoder READ step altogether. So, it is easy to structure a BOOLEAN in my vi as shown in the attachment. If I do it this way, will it throw an error, or just skip the READ until the BOOLEAN is true again? Is there a better way to prevent the READ from happening if one of my other sensor values is not within the correct range?
Thanks,
Dave
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Attachments:
forum JUly 18.vi ‏26 KB

Sure, you can put a Read inside a case structure. For your application, just check that your sensors are all within range (Comparisons palette), then AND the T/F's and use the result of that for your case structure. (If you are already doing the in-range check, I can't see it here because you have 5 subVIs that I cannot open here.
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Can I use a formula node to start the execution of a case structure?

Hi,
I am working on editing a VI to make it much easier to understand (for colleagues and non LV users). For one reason or another, the VI's creators did not fully make use of the power of case structures and other structure types. In the application we need it for, the instrument cycles and repeats measurements on several objects. We are interested in measuring the motor currents for several motors in the system. As it stands now, for each sample object's run, there is a separate sub-vi diagram which displays its waveform trace and several indicators such as max current, time at max, etc. That code was contained within a T/F case structure and copied and pasted 20 plus times.... Obviously the vi became extrememly cluttered and needed a huge screen to see. The trigger for the current case structures is an EQUALS comparison between one input (which is the sample object counter; and this part I will likely leave unchanged since it makes a lot of sense already) and a constant which was defined 1 through 20+ for case.
I have since made one case structure and 20+ instances of that case and have labeled them (at the top selection box near the detent arrows) "1", "2", 3, etc. I am wondering if I can use a formula node to act as the "trigger" which sets each case structure running? I believe that a simple IF statement should work. Please see a snippet of my attempt at making this in C below.
For the node, I defined X as the input and Y as the output. The input to the node, X, is connected to the sample object counter. The output, Y, is connected to the case selector of the case structure. My attempt at the code is below:
int32 y
For(x == 1)
y = "1";
For(x == 2)
y = "2";
etc, etc.
Is that above code snippet correct? Do i need something like "ENDIF" or "end if" at the end? Does "y" have to be defined as "int32" or can it be something else?
Thanks for the help!

Is your formula node doing anything else besides what is shown?
Why don't you just wire the value that is going into it at X directly into the selector of the case structure?
Attachments:
Example_VI_BD.png ‏2 KB

How to get a case structure to execute only once in a loop

I have a while loop that is monitoring temperature. Once the temperature meets or exceeds a given setpoint I want to start a timer. At this point I don't want to monitor the temperature anymore. That is, if the temperature should drop below the setpoint, I don't want to execute the case structure again when the temperture meets or exceeds the setpoint(the temp may oscillate about the setpoint for a given period of time). In any event, I need the case structure to execute only one time, not every iteration of the loop.

You can put a local Boolean variable "Flag" inside that case structure and
set "Flag" to False. Outside the case structure, use an "AND" function
output to control the case structure. The "AND" function has two inputs. One
goes to the comparison results between real temp and setpoint. The other
inputs connects to the "Flag" variable. In this way, once you entered that
case structure, the "Flag" will be turned to False, and then in next
iteration, you won't get into the case again because the "AND" function will
be False as your "Flag" is False now.
Hope this helps.
Rentian
1. Inside the case structure, put a
"BB Herman" wrote in message
news:[email protected]..
>I have a while loop that is monitori
ng temperature. Once the
> temperature meets or exceeds a given setpoint I want to start a timer.
> At this point I don't want to monitor the temperature anymore. That
> is, if the temperature should drop below the setpoint, I don't want to
> execute the case structure again when the temperture meets or exceeds
> the setpoint(the temp may oscillate about the setpoint for a given
> period of time). In any event, I need the case structure to execute
> only one time, not every iteration of the loop.

Problem with multiple sub-panels through Enum case structure: "The VI is not in a state compatible with this operation"

Hello,
I am using LabVIEW 8.0 and I am attempting to create a sub-panel that displays the front panel of a sub-vi depending on the selection made by the user via the Enum dropdown menu. I have wired the Enum to a case structure and applied identical coding to each individual case structure except for obviously changing the sub-vi source. However, I receive an error "The VI is not in a state compatible with this operation." I was able to successfully make a single sub-vi work within a sub-panel using a true/false case structure and the exact same coding. However, now that I am using an Enum box wired to a case structure, I receive this error. I have attached my block diagram as well. Could anyone assist me as to where it is that I am going wrong?
Thanks in advance!
Solved!
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Attachments:
enum subpanels.JPG ‏22 KB

torm wrote:
I have attached my block diagram as well
I only see a picture. Can you attach the VI instead? At what point do you close the reference?
torm wrote:
I have wired the Enum to a case structure and applied identical coding to each individual case structure except for obviously changing the sub-vi source.
Well, if the code is identical except for the source, only the source should be inside the case, right? Why duplicate code?
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The case structure is not working well on comaring two strings using true or false string matching VI

I need an execution of commands after the reply from the instrument matches with the string I provided for that i used true or false string match VI on which the true string the matching command and the string is the reply from the instrument. And I put the further executionable commands in frame after frame of sequence loop in the true of the case structure. Amd finally I given all the output strings to the concatenate string to get all the replies as one loop. But when I execute the program the desired result is not available. So kindly please help me to overcome this problem.
Attachments:
basic serial with changes.vi ‏24 KB

You VI makes absolutely no sense and I would recommend you start with a few simple LabVIEW tutorials before trying to tackle this.
What is the point of the FOR loop with 1 iteration, it might as well not even be there, same difference.
Why is there an abort primitive in the FOR loop, this mean the program will unconditionally stop abort before any downstream code will ever go into action. The program will never get past the FOR loop.
You created a circular data dependency and LabVIEW inserted a feedback node automatically, making things even worse. (see also)
You need to learn about dataflow, execution order, and data dependency.
You need to learn about the various types of tunnels (plain, autoindexing, etc.)
There is a tremendous amount of duplicate code. Large code sections are the same, differeing only by a string. You should only have one copy of that code inside a proper state machine. Have a look at the design templates and examples that ship with LabVIEW.
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Case structure with more than 200 cases, slower lab view app

Problem Description :
i am currently making a vi which compose of a simple case structures, a case structure with more than 200 cases, what i noticed is that the more i added cases the slower the labview reacts, it takes time for me to route wire on each of the cases.
i dont know if there are any setting in the labview environment that i can increase the buffer size? i dont know... but its getting slow (only on the
vi with more cases in a case structure)
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Can you clarify what you mean by "slow". Does it run more slowly or does it feel sluggish during editing?
Could you attach the actual VI?
Overall, I agree with the notion of local variable overuse. For example, you read the same local variable twice in the same case. Is there a need for this? Is there a chance that it varies between the two reads? Typically, you would place the terminal in front of the case structure and wire to all the locations where you need the value. This ensures that the data is consistent. Still, this should not cause any slowdown problem.
(On a sidenote, the code in the upper left corner is inefficient. You convert the same data to lower case with each iteration, so you might want to place this before the loop and do it only once (well, if you are lucky, LabVIEW will fold the operation, but still....). Also your "index array" operation can be replaced by autoidenxing of the 2D array on the outer loop boundary.)
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How to manage a case structure Untill a value is reached

Dear all,
I am collecting data with DAQmx and after a value is reached i want to do smthg else, for this reason i created a case structure and i put to the case selector that if a value is smaller than "10" then it is true. If it is false it should stop and do what i say even if the value gets under "10 again".
So how can i make this: "once the value is reached then do what i say even if the case selector value is back to true state after a while"
Thanks.
Kind regards.
Solved!
Go to Solution.
Attachments:
False-CaseStructure.png ‏15 KB
True-Case-Structure.png ‏19 KB

You can use the shift register to make a condition so once it enters into the value greater than limit case then it will not go to the other case even if the value goes below.
The best solution is the one you find it by yourself
Attachments:
Case Selector.vi ‏7 KB

How do I get a case structure's panel?

I am trying to place a boolean indicator within a case structure via LabVIEW scripting and am not having any luck.
I started with the following source code, which creates and populates a case structure from an array:
https://decibel.ni.com/content/docs/DOC-22703
So my code, rather than put an enum inside each case, creates some compound arithmetic and a mask for each case. This is all working fine. I now want to place boolean indicators on the front panel that correspond to each case, and this is where my problem is. I can create the indicators, but when I look at the block diagram view, all of the indicators are located outside of the case structure, rather than the indicators being inside of each respective case.
I think the reason is that a boolean indicator is created by passing a reference to the front panel. But the problem with this is that the VI panel reference does not indicate that the boolean should be placed inside the case structure, just on the panel, so when you view in block diagram mode, it's just thrown the indicators all outside the case structure and wired them up via tunnels. I am getting the panel reference by accessing the OwningVI field of my CaseSel object. I feel like there must be some field I should be able to access that indicates to put the block-diagram boolean inside of the respective case structure, but I can't find it.
I've attached a file with 3 pics in it. One shows a pic of the code I'm using to create the indicators. One shows the type of output I'm looking for. One shows the type of output I'm getting.
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Attachments:
lv_case_struct.jpg ‏221 KB

Before you connect the wire to the terminal, call the Move method on the indicator's terminal and use one of the case structure's Diagrams[] as the owner. This will move the terminal into the structure.
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Pass the value of the current case in a case structure to a global variable for use in VIs.

I have built a large queued state machine (>100 cases). In each state, I run a VI that I have created. These VIs are usually not very different from one another. In many cases, I could simply use the same VI over and over again. There is only one problem with that. None of these VIs know which case to send the program to next. I have to change the value of the "NEXT_CASE" constants in the VI and save it under a new name to be inserted into each new case. Now my program consists of hundreds of VIs whose only difference is the value of their "NEXT_CASE" constants. This causes all kind of headaches when I have to insert new cases into the state machine, and it is just too much for me to deal with.
I need to be able to use a global variable to keep track of the current case within my VIs. I could change it from a string to a number and add or subtract from it to determine which case the program should go to next. Since I'm usually only skipping from one case to the next (or the previous) I could use the exact same VI in most cases. Can anyone tell me how to create a global variable that contains the value of the case in my case structure that I could use within my VIs to keep track of the current case? Let me know if you have any questions.

Instead of defining the next state inside the subvi, why not do it in the main vi inside each state case? An output from the subvi could be used with a case structure to determine the next state. Sort of like, if the subvi returns 0 then next state is State3, else if the subvi returns 1 then next state is State4.
Message Edited by tbob on 08-19-2005 03:15 PM
- tbob
Inventor of the WORM Global
Attachments:
NextState.PNG ‏5 KB

Event structure vs case structure?

I am developing an application that is fairly user input based... lots of boolean control buttons to do different things.
In the past, I have avoided "value change" event structures, and instead went with a while loop, stacked sequence, and series of case structures. After having done it, I decided this was a terrible idea. This time, I intend to build an array from the booleans, convert it to a number, and feed it in to a single case structure. This will give me the option to add cases for different combinations of the booleans being pressed.
I guess the question is: What is the best method for doing something like this? Does one have advantages over the other?
Edit: I wasn't that clear. I would like a comparison between the "value change" event structure method, and just feeding everything in to an array -> case structure. I also am worried that with the bool array -> case structure that I will run in to problems where I end up with too many control variables, and the value of the resulting number gets ugly very quickly. The application has several buttons... next, last, save, load, several different configure setup buttons etc.
Thanks!
Solved!
Go to Solution.

Aalenox wrote:
I am developing an application that is fairly user input based... lots of boolean control buttons to do different things.
In the past, I have avoided "value change" event structures, and instead went with a while loop, stacked sequence, and series of case structures. After having done it, I decided this was a terrible idea. This time, I intend to build an array from the booleans, convert it to a number, and feed it in to a single case structure. This will give me the option to add cases for different combinations of the booleans being pressed.
I guess the question is: What is the best method for doing something like this? Does one have advantages over the other?
Edit: I wasn't that clear. I would like a comparison between the "value change" event structure method, and just feeding everything in to an array -> case structure. I also am worried that with the bool array -> case structure that I will run in to problems where I end up with too many control variables, and the value of the resulting number gets ugly very quickly. The application has several buttons... next, last, save, load, several different configure setup buttons etc.
Thanks!
Event structure. Among other things, it will allow your loop to "sleep." then wake up when an event happens. With a case structure it's going to be constantly polling. Event structure is pretty much always the right way to go in newer versions of LabVIEW that have it available. I assure you, your first solution was aboslutely wrong and you noticed that, your second is better and was common the way before event structures existed, now that event structures exist, you should go with those.
CLA, LabVIEW Versions 2010-2013

Generating a report w/ block diagram & programatically specified case structure?

Hi,
I am trying to generate a report that shows the block diagram for a programatically specific case structure.
The case structure has ~90 cases and is selected by a custom control.
I'm on Labview 8.5
I've found with the Append Block Diagram to VI, I can print out all of the cases (setting hidden frames to true), or just one case. However, I cannot select which case it shows, it always prints out whatever case has been manually selected on the block diagram, but I want to be able to programatically select it.
I've tried to do the same thing by opening a vi reference, and using BD.Get Image Scaled, and cannot get that working as desired either. I've also tried setting the value of the control before getting the image, but that doesn't help.
Any thoughts?

Probably.
This VI is backsaved to 8.5 and has the basic functionality. I don't know if the traverse VI shipped with 8.5, but hopefully this should be enough. If not, LAVA has info on how to access the scripting features in older versions (although less between 8.0 and 8.6).
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Attachments:
Visible Frame.vi ‏10 KB

Case structure is restarting at 120? should go to 167

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