Local variables and DSC module

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• local variable and high Ribbon

  I copied a VI to control the DSA8200 Tek to manage the DSA8300. I guess that all controls remain the same.

  The new DSA8300.VI is attached. Why does show DSA8200 in the top Ribbon on the front panel?

  And when I search this VI "8200", I find a local variable called "DSA8200.vi". How to change that to "DSA8300.vi"?

  I am also attaching ScopeDialog.vi, because it is called by DSA8300.vi.

  Thank you.

  efarr wrote:

  If you can shed some light on why it happened, I could learn something.

  A local variable is the name of the control on his face and that's all the information you need. If show you right-click on any variable local and it the label, the label will be the file name of the container VI. Since you have already changed the name of VI, it has already changed to DSA8300.vi. Since it is redundant information, there is no need to ever show him the label of a local variable.

  I have never shown a label of a local variable before, it was new to me too.

• LabVIEW: Concerns with local Variables and the readability of the program

  Hello everyone. I was hired for the summer to work at my University to a new laboratory. All right, but I have some problems with my main VI. I am a new user of labview coming from a C++ background. I went through several iterations of adding features, fixing bugs and doing my readable program. Before the last "cleaning" my program was so big that I couldn't see it all at once on my screen. My goal was to solve this problem. My solution contained three parts: use a state machine show parts of my code at the same time, to remove the son as much as possible, and use structures element to position my code manually.

  I met since problems write other programs that brought me here, and I saw a series of messages condemning the new programmers for their use of local variables instead of cables. I do not know my use of structures element as fancy boxes I can exclude the automatic cleaning is also a terrible practice.

  After doing some more reasearch on the subject I see local variables to add the duplicate in memory entries and their suppression can significantly speed up execution time. I have a delay programmed in a part of my code, but the rest can run as fast as he can as far as I'm concerned.

  I have attached my main program. Looking at it I think I did a good job to make it readable. But I'm not a user expert labVIEW.

  How to balance (do not use local variables, these structures element, etc.) efficiency and readability. Before you make these changes, there was so many things and so many threads all over the place that I couldn't even tell what was going on, and even less my teacher. I really wish I could see my entire program without scrolling on this computer of the laboratory (resolution 1280 x 1024).

  Advice on how I can achieve the efficiency, simplicity and common readability would be greatly appreciated. I feel I've done the latter while sacrificing the first two. Ultimately the three should probably be equally important.

  Thank you.

  Nukem

  LabVIEW 2010

  

  As said altenbach, attach your event structures.  It should really be only need structure of an event, especially for a simple VI like that (I counted 3).  This is the second time I have recommended this today, but fetch JKI State Machine.  I use as the basis for most of my interfaces.

  Here's a way to manage the break with JKI.

  

  

  

• Another question on local Variables and their use.

  I have read many many posts on forums how we avoid the use of locals at all costs because they go against the stream of LV paradigm however I tried to find a way to replace them in my programs and do not have.

  Basic explanation:

  I use a state machine to browse specific validation test steps and test of electronic equipment of base. (Panels, timers, relays moduals fuses) Many of these facilities contain LED indicator. In the tests, I took photos of the products and then used the Boolean flags to replicate the LED on the PC so that the test operators can check to make sure the equpiment LED turns on as needed. My problem is that many products contain 20 + LED and have no order to how they are turned on. Because of this that I eventually do a boolean for each LED indicator, put all the indicators in a structure of disabled, then using local Variables at each step to display on the FP LED should now be on. It's often a lot of locals throughout the program.

  I tried to make a very basic sample of VI to try to show what is a normal procedure. How can I reduce the amount of local Variables without increasing the complexity of my VI?

  If the LED change of State within the meaning of the criterion - within the case statement - you need a parallel loop.

  I did a heap of your LED and does an architecture of producer/consumer of your case, 'Test 2' attached.

  Edit: In my table, on the bottom line, the text should read "your 6 LEDS are now a Cluster" rather than "your 6 are LED not a Cluster."

• Comparative analysis of local Variable Transmission times

  Is it possible to compare the time of transmission of local variables?

  I ran some stuff simple reference before, but never something that would understand how long we had to to get a piece of data in a local variable.

  I have attached a simple program that sends information via a local variable, and there is obviously some lag which is visible, well, I'm running at least visible on the system. I know that this lag depends on the system, the program runs on so I would really like to find a way to test it on the PC we use here.

  Any ideas?

  -Ian

  No, they are not the devil as long as you are aware of their capabilities and their limitations.

  Regarding "some applications cannot always use queues or notifiers accomplish certain requirements", give me an application where you cannot use a queue or the declarant, and I bet you can.

  The problem with your 'reference', is that it's a bad test.  You do a visual aspect to two parallel while loops that have no synchronization between them.  If you used a wait until the next msec in both loops, you would see then better synchronization.  Download the file read out of the loop that could cause a random delay.

  And the biggest concern with local variables is "conditions of competition".  Search the forums to learn more about them.  You cannot control this piece of code is running in what order.  If you have two parallel two loop iterations, if the value is written to the local variable before or after that the local variable is read and written to the other indicator determines if a value new or old is used.  If it's an old value, it will be a new iteration of the loop at the bottom before it is updated.

  Search the forums for the terminals of variables local vs vs property nodes, and you will see that the local variables updated the order of milliseconds.  The only reason you see 'in the Kingdom of less than 250 ms' is because it is the rate of the iteration of the loop at the bottom.

• Copy a structure of event containing local variables

  Hello

  I am a state machine design in Labview and next state transition logic to wait be clicked a few buttons on the Panel.

  If I press a Boolean button from 1 to 9, next State should be X, otherwise condition (10 to 16 tags) should be there.

  I thought that the right approach, because it would be a structure of the event, where I added two cases: case 1 (button 1: mouse to the bottom button 2 down,..., 9 of the mouse down) and box 2 (10 mouse buttons down,...). For each of these cases, I'm reading & writing the local variable of some double digital.

  When I copy the structure of the event in another case of structure of outer case, I note the following: all cases in the event loop is missing, and the local variable renamed automatically and a new created indicator digital.

  • How to make an exact copy of the structure of the event, without the problems described above?
  • Could you suggest a different approach more effective than mine?

  Thanks for any response.

  Start by reading the guard and recommendations for using events in LabVIEW - LabVIEW 2011 help

  The fact that you try to copy and structure of the event to another, and that a structure of the event will be buried in a case initially tells me you are already heading on the wrong track and yourself in creating a world of problems.  Your architecture will never seem to work for you.

  The event structures are always active and capture events.  Even when the structure of the event is not in the path of execution, it's queue of events to which he attributed to him.  If you have events that are set to lock the façade until full, then you're really screwed because the event structure will capture the event, locking of the front panel and the execution path of your code with the state machine may never come to the specific case that has captured the event to support then release the façade.

  In general, you should have the structure of a single event in a VI, and should not be buried in a case structure where he can never carry.  You also shouldn't have several event facilities manage the same events.   These are not hard and fast rules, but until you are quite familiar with how the event structures work and completely understand the architecture of your code, you should not violate or you will just ask trouble.

  Similarly with the help of local variables.  The fact that you say that you have local variables and you try to copy tells me that you already have too many.  There is certainly a better way to build your VI, which does not require local variables with the exception of a few cases and certainly won't need several structures event buried in the structures of the case.

  You should probably have a producer/consumer architecture that handles the events.  Have a simple loop with a structure of the event which captures all user interactions.  Pass events to a loop of consumer who is also your computer through a queue of State.  (Also known as a computer state in queue or the BAU).  Let the state machine to determine how to manage the events, he received based on what is the current state of the VI.

• copy a local variable without front double element

  whenever I have copy and paste a local variable in the block diagram, LV automatically duplicate the front panel which is really awkward... is there anyway to stop the duplication of the façade?  I have look all over the place, but maybe I missed something... .Gee where that parameter could be?

  There are two ways to copy objects in LabVIEW. Of course, we're the regular copy and paste. You can also hold down the Ctrl key and click on and drag any element in LabVIEW to create a copy. It is not only faster, but this copy mechanism can be used for local Variables and related nodes of property without too much a copy of the associated control. Check it out!

• automatic creation of local variables

  Hello

  I have the impression that the idea I have is probably not possible, but I thought it wouldn't hurt to ask.  I connect CAN data using a cRIO and NI 9853 using the framework on the channel of convertion vi.  I have a selector of cases in which the message id dictates the case.  In each case, the raster data are converted and sent to tables for data and the name of the channel.  Then, in a separate loop, I make every tenth iteration in the name of channel and data with local variables and save it to a file of PDM.  I currently use local variables for each table in the selector of the case.  While this works well, I'm trying to simplify it and make it like if someone wanted to add several CAN signals for forest exploitation and so more cases in the selector of the case, they could do with as little work as possible.  In essence, I need to make fake evidence.  The idea that I'm trying to find a way to create a local variable and a specific reference indicator as soon as a case is created automatically.  Is it possible, or I ask much of labview?  Thank you.

  
  

• sons are better than local variables?

  Hello

  I built a vi that eventually became huge with lots of sequence and case. Local variables of course reduces a lot of threads, but at the same time consumes memory. So those who are better? son of current throughout the vi or local variables?

  Concerning

  Simo

  The sons are better.

  DataFlow vs Local Variables

  variables local vs DataFlow

  Another question on local Variables and their use

  Why some people say that local Variables are bad

• A list allows you to select a local variable to draw

  I have a few tables of point 2D locations stored in local variables.  For diagnostic purposes, I would like to be able to select a (all) of these current local variables and plot.  I can do this one at a time by indexing the table, and adding a 255 to the value of each pair of coordinates in table z, then all indexed to a curve of intensity.  Setting a period of time allows me to "look" at the position of the points in the table as they are drawn.  I know that none of you have had problems with the line, col x, y reversals and others, but I need something to help me visualize these interactions.  Browsing through the simultaneous plot of two of these tables would allow me to see what points focus on others I'm working on the berries.  Rather than having to 'program' whenever I wanted to get the location of the points of view, I would rather chosen them from a list of a few little vi I could run any time I wanted... How can you go about this?  Or is there a better way.

  Basically, how to complete scrutiny of the enumeration with the list of local variables?

  Thank you.

  You cannot change the labels for an enum during execution.  However, you can use a drop-down list (right next to the enum) who will do exactly what you want.  Just use the property "Tags" to set all the elements for the control.

  Bruce

• update of local variables

  I want to acess the value of a variable outside a befor even loop the loop is completed, so I am trying to create a local variable and use it to transfer data outside the loop to do simultaneous online processing.

  However, I am only able to update a flag outside of the loop with the variable name put to day... but if I pull a wire from there to do a treatment of value in the thread is not updated...

  I tried both versions and update the same... only one digital indicator is updated... numeric2 isn't always updated... Why?

  How can it be resolved?

  During the iteration of the inner loop of the outer loop will not update. See an example of a quick fix LV 8.6.1. Try not to use local variables unless absoulutely necessary.

• How to read the values of the variables of façade in loops without using local variables or property value nodes?

  I know that local variables and nodes of property value are causing a lot of problems.

  But if I read the value of a variable front outside a loop.

  the value is only read once before the start of the loop.

  Changed the front variable values during the iterations of the loop, is invisible.

  How can I solve this problem?

  
  

• Write to the faster local variable in 2010?

  I remember a demo of LabVIEW classes which compared to the speed of writing directly to an indicator compared to a local variable and the property node.

  I thought that writing to a local variable has been very slow compared to writing to a terminal. There is no difference that I see with 2010. Maybe I'm not remembering correctly but I know that the gurus OR did a lot of performance optimizations.

  I have more 2009. A person of 2009 or an earlier version can tell me what's the difference in speed between writing to a terminal in the attached vi vs local?

  OR put in place a dorr back to allow the local update quickly. Not as fast as the terminal but fast.

  The draw on the spell-back cmoes in force when you have multiple.

  If you have a large table, you update (big table will make it easier to reference) and there are 20 places that read through local, then the dat should be copied in other residents.

  Ben

• How is it my local variable is not updated its value compared to what is happening in the while loop?

  Hello

  I am trying to extract data from a time that my statements updated in what concerns the number of loop iteration. I tried to use the two local variables and travel records, but without success.

  I also did the following example: http://www.ni.com/white-paper/7585/en and it works like a charm.

  I've attached the PNG file with declaration of the local variable circled in red. Join a VI in the next respnose.

  Thank you

  No, the two while loops are stacked and not parallel, which means the outer loop cannot go to the next iteration until all code in this document, including the inside so that the loop is finished.

• PLSQL local variable assigned to a global package

  I have a situation I want to declare a local variable and assign it to a global package variable.

  such as:

  xyz package_a.my_type := package_a.my_var
  

  This creates a pointer to the global package or Oracle copy the global variable?  I need for oracle deal with this pointer.

  Is there something wrong with that?

  If there is no problem, I'll adopt this approach in 100s of procedures / packages.  I use oracle psp and create a large number of procedures.

  Hello

  Do you really need a separate variable xyz?  Why not just use package_a.my_var?

  What is the big picture here?  What you trying to do?  Explain your business needs, and someone will help you to find a good way to respond.

  What you've posted describes only one way that you thought to meet the requirement; We can guess the real requirement, and guess is not the best way to solve problems.