Modify Case structure with VI Scripting

This is possible:
you need a file, where only a case structure is on the BlockDiagram (BD).
This file is called (e.g. Test1.vi)
Then you start this VI:
And in your test1.vi you have updated the case structure ( CaseStructure ) with VI Scripting
Sometimes you will need this
BR
Eugen Wiebe
Eugen Wiebe
Bernstein AG
CLAD - Certified LabView Associate Developer

I now understand what you were saying about inlining a subvi. I did as you said and made a subvi with a case structure and an indicator within it. I use the New VI Object node to add that subvi to the slow-inlining parent VI. Then I tried to inline it using the invoke node, but I got error 1399, which make sense. Is this what you meant for me to do, or did I misunderstand?
Also, I tried the ControlTerminal reference approach you mentioned earlier. Unfortunately when I called the move method on the control terminal property and had the 0th frame of the case structure as the owner I got error 1060 again.
I really appreciate your help. Do you have any other thoughts?

Similar Messages

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)
mytestautomation.com
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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.)
LabVIEW Champion . Do more with less code and in less time .

How can I put a numeric indicator into a case structure using VI scripting

I'm using VI scripting and I'm trying to add a numeric indicator inside a case structure. I'm able to add the case structure and the numeric indicator just fine, but as soon as I specify the case structure as the "owner" of the numeric (as opposed to the block diagram being the owner) I get error 1060. Is there any way around this?
Note: The reason I am doing this is because this specific pattern (indicator in a case structure) will prevent a VI from being inlined when it is being built. This pattern will provide no functionality in itself, it only prevents the inlining. It is added to a larger VI which is use to initialize objects in a simulation, and there are many of them in the total simulation. If they are inlined, it takes a VERY long time to generate the C code, and performance on this VI isn't an issue since it is performed only once at the beginning of the simulation. The rest of the VIs do need to be inlined for performance reasons. Therefore, I'm open to other options to prevent a VIs from being inlined if the "indicator in a case structure" cannot be performed via scripting.
If any of this is unclear please let me know and I can clarify. Thanks.
Solved!
Go to Solution.

I now understand what you were saying about inlining a subvi. I did as you said and made a subvi with a case structure and an indicator within it. I use the New VI Object node to add that subvi to the slow-inlining parent VI. Then I tried to inline it using the invoke node, but I got error 1399, which make sense. Is this what you meant for me to do, or did I misunderstand?
Also, I tried the ControlTerminal reference approach you mentioned earlier. Unfortunately when I called the move method on the control terminal property and had the 0th frame of the case structure as the owner I got error 1060 again.
I really appreciate your help. Do you have any other thoughts?

How do I use a Case Structure with Strings?

I need to use a string list to set up a set of cases to be performed. Is it possible to tell a single case structure to do "a, b, c, and d, but not e or f" or "do a, c, d, and f, but not b or e" etc... when you use a string containing the cases to be used?

Blackavar,
A case structure will only execute a single case at a time. If you want to have multiple cases execute in parallel, then you would need to have multiple copies of the case structure and split the string apart and wire them to all of the needed case structures.
This could be done with reentrant subVIs to run truely in parallel. Anther method would be to have 6 different case structures, all with 7 cases each. The 7 cases would be "a", "b", "c", "d", "e", "f", and "0". Your input sting will need to be built up so that it will always be 6 characters long and then split up so that each character goes to one of the case structures. You would have your needed code for cases a - f. Case "0" would do nothing.
Randy Hos
kin
Applications Engineer
Nationsl Instruments
http://www.ni.com/ask

CASE STRUCTURES WITH TAB CONTROL

Hi,
I have created tab controlled case structures for three different cases,
Tablet type
Machine Input
Output
It seems that data is not interlinked while switching betweeen the cases.
I have to select the start buttun for each tab to get results.And also if I skip the second tab and jump to third tab, it doesnot give results. SOmehow the data is not acquired.
Can anyone help me out for the same.
Attached is the main VI (PAR_LAB_ATT_00_01)followed by a sub VI(gen time array)
Thanks
Sumit
Attachments:
PAR_LAB_ATT_00_01.vi ‏200 KB
Generate Time Array.vi ‏15 KB

Please don't use all CAPS when posting your message subject.
How are you running your VI? I don't see any while loop in it, so it only runs once. Which means only the case structure associated with the tab that is currently highlighted before you press the run button will actually run.
The vast majority of the time, a tab control is only used to control what is displayed in the front panel and is not used to actually control the execution order of the program.
I would recommend looking at the online LabVIEW tutorials
LabVIEW Introduction Course - Three Hours
LabVIEW Introduction Course - Six Hours

Execute Case Structure with Button Press Slows Down VI

Hi -
I'm fairly new to LabView, and I am having some issues with using a button to run a timed while loop.
I am writing a VI that outputs a timed voltage pulse to an output channel on a DAQ; meanwhile, the VI reads and graphs the voltage on three input channels on the DAQ. When I use a timed loop that automatically executes when the VI runs, the program works. However, I would like to include a button so I can control the timing and number of voltage pulses sent to the output channel, instead of sending only one voltage pulse each time the VI runs. I have tried to do this using a button wired to a case structure. If the button is 'true,' the VI should send the voltage pulse. If the button is 'false,' the VI should keep the voltage at zero.
When the button is 'false,' the VI runs normally; however, when the button changes to 'true,' the VI slows down and never sends the pulse. Why does this happen? How can I fix it?
Also, how can I send the voltage pulse only when the value of the button changes? I only want the timed loop to execute once when the button changes value.
Thanks for any help or advice!!!
Attachments:
Sensor Read6.vi ‏85 KB

The graph is in the same while loop as the case structure. The while loop won't iterate until all the code inside of it has completed. So the graph only gets updated once, and won't update again until the while loop iterates again. If you need more continual updating you may want to put that in a loop that executes a couple of times, or completely separate your code into 2 while loops. Is it that long of a wait considering your pulse length is 1 second?
Your analog output code is just writing a voltage out (7 volts) until it eventually writes out 0 volts. There is no reason for it to drop down unless you have some sort of electrical problem between your DAQ device and the device on the other end that is reading the 7 volts. What are you connecting that analog output too?
What if you don't use LabVIEW and try to test out that analog output using Measurement and Automation Explorer? Does it do the same thing?

How about an Error Case structure with warning?

Hi,
while wiring some vis and thinking about error handling....
In most cases the simple case structure feet by the error cluster will do the job. However in some cases when you deal with warnings, wouldn't it be nice to have an additional (optional) warning case that is true for a not empty source string and/or an error number?
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'

I forget to mention: Of course there is a solution possible by unbundling the cluster and check the error number and string followed by a case. I still remember the time when the case selector couldn't handle the error cluster ... (started with LV3.1 )
I just thought it would be a nice thing when you wire the error cluster to the selector and get the red and green case and you can right click, add a case and get a yellow(?) case named 'warning'
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'
Attachments:
Example_BD.png ‏2 KB

Case structure with two selectors

Hi all
Once again I'm wondering...
...if it is possible to wire more than one value to a case structure. I'm just working on a project and came to a point where I have to nest case structures. I have two enums and depending on both enums I set a value.
How would it be to have more selectors so that the following code extract could be "drawn" with just one case structure?
enum X1 = {manual, auto}
enum X2 = {red, green}
if(X1 == manual && X2 == red)
else if(X1 == auto && X2 == red)
Maybe something useful for new LV versions, if it does not exist yet.
Thomas
Using LV8.0
Don't be afraid to rate a good answer...

@David - Great solution. I might remember it one day .
@Shane - You could have given me at least "en stutz" . Well, I see your point, but in every textual language exists this possibility. Although your argument is acceptable (the compound enum), I prefer to have enums without combinations. Ok, maybe the values would make some sense, but I like it better if they are separate. In addition, what should I do if one input is an enum and the other a boolean? And now don't say "use DavidCrawford's solution" .
Thomas
Using LV8.0
Don't be afraid to rate a good answer...

Building a case structure with four boolean (true/false) inputs.

I currently have two boolean inputs that I would like to use to select cases in a case structure. I would like to have four cases, each one dependent on the true/false condtions of the two booleans. If boolean 1 =true, then case 1 should be used, if boolean 2=true, then case 2 should be used, etc.
What structure should I use to convert these boolean inputs into numeric cases?

Or build them in to an array and "Search 1d Array". If you are only looking for a single bool being true, this would be easier because your cases could be {0,1,2,3} instead of {1,2,4,8}

Modify the footer with java-script

Hi,
Im' trying to modify the content of the footer in the master-page using java-script. So I put in the initialize event of the footer code to add "!" after a text field (with plenty of space left) but it doesn't do anything. The code is example.rawValue = example.rawValue + "!";
This code works fine in the rest of the document, but it doesn't seem to work in the master-page.
Could somebody tell me what I'm doing wrong?
Thanks in advance!
Gert

The access to the masterpage objects is not in the same scope as where the script is running so you must path to it starting from the root:
so.... form1.pageSet.Page1.example.rawValue = form1.pageSet.Page1.example.rawValue + "!";
where form1 is the root node of your form (look in the hierarchy view), pageSet indicates the objects in the Master Pages, Page1 is the 1st Page name in the Master Pages and exampel is the path to th erest of the object.
Make sense?

Case structure with arrays

why don't the array values are not shown in array 0 and array 1 in the enclosed attchment array0.vi.
thanks
Attachments:
array0.vi ‏14 KB

Then default value then NOT wired is an empty array. So using array 0, as an example. It will be filled with data on iteration 0. But this data will be overwritten with an empty array. In the next iterations.
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

Is there a known issue with emailing from case structures

Hi,
I am working on a quality control vi for data coming in as a text string. I need to be able to have the vi perform a check with the responce to the check (true or false) will cause different steps to then be performed. I was able to get the vi to perform 1 check and email out if the responce was false. When I tried to add a second check if the responce was true, the vi would run without any errors but would not email out or would only email out from the first check even if the first check passed and it was the second check that failed. This was all done without case structures. I then started using case structures with the true responce leading to other checks but the false responce leading to an email generation. For some reason even a simple one check with the email generation happening in the false case will not work. There are no errors or anything, it goes through the whole process correctly but will not send an email. Please help!!
Tim Koles

Hi,
Here is the vi and the sample text file it calls for. You will of course have to change the path name. Feel free to call me if you have any other questions. Thanks
Tim
410-326-7259
Attachments:
SPLIT_WEATHER15.TXT ‏130 KB
Weather QCexample.vi ‏63 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.
Solved!
Go to Solution.
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.
Try to take over the world!

Multiple booleans controlling one boolean input for a case structure

Hello,
I have four boolean buttons and a case structure with a boolean input. I would like to write the program so that whenever any one of the four boolean button changes value, the case structure reads true for one loop interation, and then returns to false.
I have tried all sorts of things and can't seem to figure it out.
Ultimately, the ideal function of the program is so that whenever you push any one of the four boolean voltage controllers, that voltage case is chosen in the case structure, the time in seconds is written to a file, and the elapsed time timer is reset.
I have attached my program. Let me know if you have suggestions. Thanks.
Attachments:
Volt_Control_And_Time_Counter.vi ‏71 KB

Zappow wrote:
However, with this setup, the time counter still doesn't work.
The event structure for all four buttons has a true boolean constant connected to my file-saving case structure. If I connect this to my elapsed time express VI reset button, the timer doesn't count.
The timer does not count because you have not wired a timeout to the lower event structure. The default timeout is -1, so the lower loop never spins via timeout
It is useless to have a wait in a loop that also has a timeout case. Just wire an approriate timeout value to the timeout terminal and remove all waits. It is also not necessary to have a 1ms ttimeout if your timeout values only displays to 100ms resolution. Can you explain why you think you need two loops and all that extra code?
Attached is a quick rewrite that solves some of the problem. Since I don't have any hardware, I replace the voltage out with a meter.
You have way too many FP controls and indicators. Use arrays!
Let me know if yo have any questions. Modify as needed.
LabVIEW Champion . Do more with less code and in less time .
Attachments:
Volt_Control_And_Time_CounterMOD.vi ‏63 KB

How can I have multiple inputs into the selector terminal of a case structure

Hi everyone
I have a question on how to wire multiple inputs in to the selector terminal of a case structure.
Currently, I have three switches, each switch determines different case. So if I switch the switch 1 is on, the numeric indicator will show 1. If the switch 2 is on, the numeric indicator will show 2, so on and so forth. However, the selector terminal will not allow me to wire multiply inputs into the case structure, I tried Bundle by Name, Bundle and Array to Cluster, but they did not work. I set the case structure with 3 cases, they are 1, 2 and 3.
Could someone help me please. I have attach an image and the VI of the work I did so far.
I have another question, is there a function which can toggle other switches to off when there is a switch has been toggled on.
Thank you very much
Tommy
Attachments:
Trial - Case Structure.vi ‏7 KB

Tommy, attached find a cheeseball way of doing this that has given me a LOT of mileage over the years. IT lends itself nicely to a couple of really good practices that NI recommend, but I have given you the bare-bones to "see under the hood".
The recommended practices:
1. You can make this a nice tight sub-vi where you can put it into a core library of routines that you'll use over the years, even extending the logic to look only for changes, etc.
2. If you are thinking about Front Panel design considerations, you'll want to use arrays of controls where possible, as that's a nice neat way of containerizing your switch for both the FP and Block Diagram.
Have fun. I have TONS of these types of things, so feel free to PM me if you have any other needs.
Wes
Wes Ramm, Cyth UK
CLD, CPLI
Attachments:
Boolean Switch Logic.vi ‏11 KB

Modify Case structure with VI Scripting

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