Comparative analysis of local Variable Transmission times

Similar Questions

• 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

• Use of global variable from local variables for business rules

  Someone at - it guidelines on the use of overall compared to the local variables for the business rules? I really don't like the world no matter what, so if someone has a compelling reason to use overall.
  
  If I use a local variable in the world, is there a single character required for the local variable or no problem with the help of the same name local var in all of business rules.
  
  Thank you

  Hello

  I bet you have a background in programming. Don't let the 'global' nomenclature lure you into thinking that "bad design - not encapsulated, etc" with regard to business rules. According to John, this area, variable overall are a vehicle to reduce maintenance.

  For example if you have a variable in which all its used BR called CurrMonth and its always the current month, it create once, maintain his assignment in one place and use it anywhere. In this case 'global' is in fact less.

  Kind regards
  Robb Salzmann

• Local variables are comparable to the value property of a control or indicator?

  I use the buttons / switches mechanical locking action, event structures and local variables to track the status of my switches.  I used local variables with indicators, too.  Now I see that this could be done via the node property of a switch or an indicator.  Should I use the nodes property instead of local variables?  Should I use "switch" mechanical action and control the State of the control buttons / switches?  I used a mechanical locking action because it automatically reset when it is read, but who pushed me in the use of local variables.

  I know the property values to adapt the data flow model, while local variables might be placed in a sequence structure to ensure the order of execution.

  I just don't want my program all except if it is a correct approach.

  Thank you

  DH

  Dark Hollow says:

  Well, I'm changing the properties of user interface in my state machine.  For example, when you push a button to START the TEST, I want to disable and gray this button and activate the button to STOP the TEST.

  No engineer too much. In this case, you can use a single button and label the FALSE case a 'start Test' and the REAL case as TEST 'STOP '. No additional code needed at all. At the same time, you only use the half-Panel space! (and 10% space diagram!)

  Dark Hollow says:

  Another example... I have a couple of dozens of LEDs on the front panel to show the TEST SUCCEEDED.  If I have the wiring all of them, my state machine diagram gets messy.

  Define disorder! In my mind, code is not held together by wire is much messier because it is impossible to determine the order of execution and so program logic. A thread is a small 1 d object. A property node is a significant 2D object. 20 wires are much less messy than 20 knots of property, especially given that each property nodes still hanging by a thread in one way or another!

  In order to reduce the number of threads, use the most appropriate data structures. Instead of a few dozen sighted use a single Bay of LED. A single wire! Keep the table in a shift register and update alone LED as necessary by using "replace subset of the table".

• pure example to compare the performance of reading for a local variable, a declarant and a queue element (looking for)

  Dear users,

  I came across an example of the operation and the disadvantages of using a local variable, a declarant and a queue for the collection and handling of data these last time. But I can't find him.

  I try to describe what and I hope someone can give me a hint:

  A sinus values were generated periodically and were sent to an indicator, a declarant and a queue. In the other loops, the local variable (of the indicator), the authors of notifications and of the elements of the queue were plotted graphs. Time of the playback loop loops can be set separately for each of them and depends on the sync settings (time: equal to the generator, half of the generator and copy of the generator), we can observe omitted elements or duplicate. Very useful to observe the behavior of loops in a local variable, a declarant and a part of the reading queue.

  Does anyone have an idea where this VI is placed, please?

  Hello ghighuphu,

  Do you mean this example?

  With the help of local Variables, queues and notifiers to synchronize data with parallel loops.

  http://www.NI.com/example/28717/en/

  Best regards

  Maha

• 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.

• In collaboration with a no engine in the types of different scheme (local variables).

  The program below is used to control a motor with the NI 9401. However, it has been designed to work in two ways, when you push the buttom "adelante" or "ago" he turns in one direction or another, but if you press 'Start' it begin to move in a particular way (which I mentioned) and if you press again the same ('Start'), we need to stop (this way you can push the door "adelante" or "ago" If you want to). The problem I have is with the "local variables", because when the 'Start' button is the I three while loop and I Don t know how said it stops when the 'Start' button has been pushed and the same when the 'Start' button is pushed, and I press the 'Start' button to stop it. I have a mess with the function of local variables.

  I know it's a little complicated to understand by Word, I tried to explain more clearly.  I hope you can help me.

  Hello matt198717,

  Yes, I think that the problem was trying to use local variables in parallel loops. I use this property at the time of the node and it works!.

• How to set multiple values clustered with local variable?

  Hi all

  Okay, I made my way through Labview for everyone and have some basic concepts down. I can see with a cluster, if acting directly on it, you can ungroup, change values, rebundle, etc..

  I try something a little more complex... and just do not know how to start on this.

  I have a menu menu ring set. I created this with a typedef, with 4 values.  I used this typedef 7 times, more a few LED bool, in a cluster. I made this cluster a typedef.

  Therefore, in my main vi, I started designing, I put an example posted here... and inside, I have two instantiations of the typedef cluster commands selection of left and right.

  I dropped in this vi, a copy of the menu ring typedef (same typedef as in clusters, values) called reset all tubes.

  Now, I am trying to understand how, with an event to change the value to 'reset all the tubes'... that I can start with the left switch and change all tubes (here is the menu ring selector) to the same value as what has been selected with the ring of menu 'Reset all the tubes'.

  I created a local variable for the selector on the left. It is configured to read values. (I'll be doing the same thing with the right too, but just to start with the left).

  In the examples I've seen where access to a cluster, you could ungroup the cluster... browse and change the values... maybe pull out all the "hits" in a table and go through to update the values.  And when you group or ungroup the bunch... you can see the values, etc., when you stretch on the block diagram.

  With the local variable... I do not see to 'stretch' it as I expected... so I can access the values "tubes"... and all at the value of the 'reset all the tubes' ring menu value.

  Someone can put me on the path on the best way to do... or is it a component structure I'm missing here?  Am that I on the right track everything first here?

  It seems pretty basic to me, but miss me just something here on the way to start...

  Thank you in advance,

  Cayenne

  You can't do this with a for loop of how the Department is structured, but why make it so complicated?  Just group the new value in the cluster, as shown below:

  

  If you do not want to use a loop for example, consider the restructuring of your cluster.  Group ring and a Boolean value in a cluster, and then unmold 7 of those in the cluster of selector.  Then you can use 'cluster to the table' and 'picture of cluster' for all elements of the external cluster will be of the same type.

  Also, be careful when using rings in the form of type definitions.  You probably want to use an enumeration instead.  The elements of a ring do not update the when you update the type definition because they are considered to be cosmetics. the elements of a definition of enumeration type update, because the elements of an enumeration are considered as part of the data type.

• Code to skip the steps: initialization of local variables failed

  Hi all

  I'm upgrading some software LabVIEW RT I inherited LabVIEW 2011 to 2015 LabVIEW (32-bit) on a host Windows 7 Professional PC. The target is an SMU-8135. The software ran well when it is compiled under LabVIEW 2011.

  I modified the code to enable the monitoring of what is happening by looking at screen on the target outputs. The initial error that brought me here is that a local cluster variable initialized in the first window of the flat sequence described below have been appearing as the in windows later.

  The code begins with the initialization of local variables in the first window of a flat sequence and provides a quick line of text output to the display of the target (call this text #1) (using RT Debug String.vi) I send two lines of text so that a new row is created and later text does not replace it. . It then writes to the next window in the sequence flat screen two groups of text output to the target. Second text in the window 2 (#3 text) output is equipped with a wire entry from the error from the first text output in the second window (text #2). That is the second exit must wait for the first exit to complete before being sent to the screen.

  I see now some weird symptoms:

  1. when I connect to the target under a remote debugging session I see expected display outputs. Not remotely connected, text #2 is displayed. The code passes to the third window in the flat sequence, so everything in the two window should have executed.

  2. the text #1 appears on the target screen * before * I get the message "Welcome to LabVIEW Real-time 15.0." Is this normal? Whence this message? I searched my screws and subvis to this text and it is not there then it mucst come LabVIEW screws somehow.

  This all started with local variables no initialization in the first window, so apparently, I have a problem of data flow. Given that the problem disappears under the remote debugging, I'm a bit of a loss.

  Thanks in advance for any help,

  Eamonn McKernan

  EamonnMcKernan wrote:

  Text 2 appears only when remotely connected it does not appear when running at startup.

  Your "text 2" seems to be powered by a collection of nodes comments to "initialize on compile or load.  This will return once the empty string the first and therefore should not be display nothing until the code I run a second time.  That is the crux of feedback for?

• 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

• LabVIEW 2010 local variable behavior

  HI -.

  I upgraded to LabVIEW 2010 of 2009SP1 and the attached sub that VI no longer works correctly.  It is a case of State machine structure that is called inside a loop.  I will put a Boolean variable true local, then on the next appeal when the case changes the variable has been reset to false. He has not done this in LV2009.

  Someone tell me immediately I have a race condition, but these local variables are not be written anywhere else, just in these separate cases.

  See the attached code, specifically, the local variable 'Activate' is to reset during the passage of the 'turn on' case for case "power."

  Anyone else seen elsewhere deliver, or can shed some light?

  I've corrected the VI by writing the value in each case, but this different behavior I wonder what are the other issues lurking in LV2010?

  Thank you

  This code looks more like a kind of a motor of Action that a state machine, but not quite.  It is called several times since a state machine, and he decides who will be the next State according to the entries.  Instead of using all local variables, I would use shift registers not initialized (Nothing cable on the left side).  They hold their value of one call to the other.  A case more will need to be added in this case.  An event of default without a name, which would set the initial values of all the shift registers.  Make the default case and does the same name.  It will be called first automatically because the shift register is not initialized, then the default value will be called.  Inside the default case, set all the shift fits to the desired values.  Next time the Subvi is called, these values will always be there.  As long as nothing is wired on the left side, everything is wired for the shift state register will be the next case called.

  See attached vi.  It's broken because I have this thread not to indicators.

• Local Variable is NOT being updated?

  Hi all

  Please see the attached picture for the problem that I am facing. Basically, I want to open multiple files in a folder and file names allows you to derive the other names of files in a different folder and plot the data in all the files.

  Here's what I do:

  1. use the file dialog box to select files

  2. create a local variable to 'selected files' - see below

  3. derive from new files "new files" using the "selected files" and make a local variable of the "new files".

  4 plot data of "selected files".

  5. Drawing data from the files of 'new '.

  The reason for the local variables is that I will access files original and derived from many places in my VI and I want to avoid the eternal wiring or by opening the file several times dialog box (less clicking - my figure of index hurts )

  Problem: Data from "selected files" get traced. However, given "new files" are NOT given in the 'new' files to run it, but run a previous data. Apparently, the local variable "new files" does not get UPDATES

  with the "new files" of the current run. I have to run my VI twice. Why is this? How can I solve this problem?

  

  
  

• Initialization of a local Variable (variable uninitialized perhaps, but it is initialized?)

  I have behaviors very weird with my code. Some error messages complaining about reference uninitialized variables has led me to search around and found out that the shareware I use has very little initialization of local variables. CVI gives warning of the compiler on these variables, and I don't think he has caught even near each other. I went through the whole file and initialized everything myself.

  Even after that I booted my variables, however, the compiler always indicates they are unitialized, and my code still does not work. I've attached a screen of warnings from the compiler as well as one of the problem functions. Note that in the first warning (36, 9 WARNING: variable '(*tw1).i' maybe is not initialized when used here) there two notes under it, the one who told me where the variable is declared and who says "1, 1 Note: Add initialization to silence this warning. When I double-click on that note, he points to the top of the file, as if he says me to initialize the variable outside the function.

  I also found a very similar post about this but the user has said they were defining the structure twice.

  http://forums.NI.com/T5/LabWindows-CVI/local-array-initializations-not-recognized/m-p/2638119/highli...

  In addition, I understand that the screenshot I've not yet initialized the members of the struct, which I intend to do once that I get rid of these warnings.

  What should I do to remove this error? Any help is greatly appreciated, I've been messing around with this for too long. Thank you!

  emoser,

  I think that the strange warning is due to a bug in the analysis of the variables uninitialized in the compiler. The inaccurate diagnostic tests is issued at the line where you set a variable of local pointer to structure kiss_fft_cpx. It seems that the warning is caused during the pointer variable declaration is immediately followed by a local declaration of a structure of the same type:

  kiss_fft_cpx * tw1 = NULL;

  kiss_fft_cpx t;

  Basically, the incorrect diagnosis will happen:

  1. If a local pointer to a typedef struct variable is followed by a statement of the same variable type.
  2. If the second local variable declaration is not initialized.
  3. It doesn't matter if the pointer variable is initialized or not.

  The bug can come because the compiler can guess that the region of memory in the data segment continues from the pointer variable through the definition of the second variable, because they are of the same base type. A possible workaround in your case would be to go to the declaration of the variables of the same type (in your case, the declaration of the variable t) before the declaration of the pointer:

  kiss_fft_cpx t;

  kiss_fft_cpx * tw1 = NULL;

  Fortunately, this problem is fixed in the latest version of 2015 LabWindows/CVI.

  I hope this helps. I would like to know if the workaround works for you.

  Best regards!

  -Johannes

• FOR loop does not update the local Variable

  I am newer to labview, and I can't wrap the head around why not a habit of local variable to update in the code if it updates on the dashboard. Anything im missing?

  Assume that you are talking about the local variable of the 'State of the cell. The terminal updates every 500ms in the small top loop, the local variable indicates simply that the indicator and thus updates also.

  The problem is "dataflow" and you need to familiarize yourself with the concept!

  Once the while loop starts, the local variable is reading and inside the loop begins. Most likely, the local variable is read before it is updated in the small loop, so most likely returns the value of a fade on the first iteration of the while loop. Now the small loop continues to go twice per second for about five seconds. Only after the loop FOR (and everything else inside the while loop) completed, the while loop will go to the next iteration, date on which the local variable is read once more, this time with the last value of the last for loop iteration of the previous iteration of the while loop.

  In summary, the local variable updates very well, it's just that the code does not read the new value around most of the time.

  Your VI is full also potential competition conditions caused by the over-use of the local variable. You need to respect the proper execution order by eliminating local variables.

  So what is the solution? Hard to say without knowing what the VI is supposed to do. Most likely, you will need to remove the inside OF the loop and use it outside while loop for everything.