Notofication, local variable which is the efficient education Department

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• 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 find the steps associated with a local variable?

  In a sequence, we have to write or read from a local variable. Is it possible (for example right-click the variable) to find out related measures?

  Thank you!

  Are you talking about discover what steps use the local variable.  Because the measures are not really "related" variables.  Either they are or they aren't.

  You can use the search/replace tool.  Edit > find/replace

  In the look for:, enter inhabitants.

  You can check her search for: box, and then select the order in which you want to search.  This should show you a list of all instances of the local variable.

  Hope this helps,

• Structure of the event to local variable

  Hello

  I use a control structure and the table event to detect changes in the value of table.

  At the beginning, I have made changes in the table (for execution) and structure of the detected event.

  The next step was adding a parallel while loop in which I write for the control array (using the local variable).

  During execution the layout of the table changed indeed, but the structure of the event is a not detect it.

  I have attached 2 digits: 1) loop of the structure of the event 2) the parallel loop.

  It is possible works in such a way?

  How can I make the structure of the event to detect changes in the software in the control array?

  Thank you

  Leonid

  Changes made via a local variable are not the user events, so the structure of the event will not detect by definition. You must write to the command by using the property node "Value (follow the signs).

  That said, your small watch of your code starts to raise red flags in my mind with the use of variable and global variable local. While it's not bad, their abuse can lead to the poor programming architecture and race conditions. Perhaps you should consider downloading your VI any kind can someone take a look and offer suggestions on improving it.

• 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.

  

  

  

• 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".

• Update zone drop-down list programmatically does not update its local variable

  Hi all

  I followed a Web site tutorial OR and programmatically change the items in a drop-down list box. It worked successfully, but not for local variables. Local variables while keeping the elements that had it before.

  Any suggestions?

  Thank you!

  

  You must update programmatically property value to change which returns the local variable, the value that you will wire does not match with one of the array strings.

  Maybe you need to do something like this to update your value to change the 'Two' to 'five '.

  

• My approach to local variables...

  I want to hear comments on this approach.

  I create a relatively large program, and I want to use offscreen indicators / controls as "local variables".

  I think having that in a cluster - typedef, called "local variables", which I can then fitting differnet of VI and it cleans up the code a bit (but adds above makes it less clear what is happening).

  You guys/girls think this approach?

  
  

• Shift register to replace local variables

  Hello

  I'm looking for a way to make a marquee on a Boolean LED. Currently, I use a local variable to make the scrolling action (see the code, the loop For on the right). However, this method requires CPU more power and also prone to several other error. Therefore, can someone help me to replace local variables with shift register? If possible, do not change the other loop. Thank you.

  -l' scrolling action must be continuous

  -use the attached config. file

  -allows to test with any text message

  Why do you think that you need so many loops?

  Try this, perhaps this may give you some ideas...

  (Look at buffer allocations. My table of Boolean 2D works at constant size and completely in place. Not only were constantly read and write to and from the local variables, you were also constantly growing and reducing the size of the table. It's very ineffiicient. I don't see the purpose of your outside while loop or FOR your first loop. None of your shift registers makes a lot of sense. You probably want to close the file of configuration (not shown in my modification)).

• 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."

• How to determine the number of rows in the database and save the result to a local variable?

  Hello

  I'm a newbie in the use of TestStand, databases and SQL, and now I've met difficulties. I use TestStand 2014 (32 bit).

  I have a need to know the number of rows in a database and save that number in a local variable. I tried to practice using the database of the Types of step provided with TS. I tried to use the following in a SQL statement:

  Locals.NumberOfRows = ("SELECT COUNT (*) FROM TEST_TABLE")

  It returns an error: specified value is not the expected type. My goal is possible in this way, or I'm doing this completely wrong?

  -RautSa

  Thank you for your response, Norbert. I have a database of who wins new values at random, and sometimes I need the exact number of rows in this table.

  I managed to achieve my goal by using the SQL statement: "SELECT COUNT (*) as Rowcount OF TEST_TABLE", followed by a data GET operation, which records that number of lines in a local variable.

  -RautSa

• Why flatten data chain not getting past all about TestStand via a local variable of the string?

  I tried to go around a series of data in TestStand as a string using "flattened chain" of LabVIEW. When I create a local variable in TestStand of type 'string' and try to write the cluster flattened at this that he simply not transmitted. If I convert the string flat binary table and then pass it around, I can recover all the data very well.

  Is there something I'm missing here?

  I've attached an example Teststand sequence that illustrates this problem. If you run this sequence that the 1st test will fail, which is the attempt to simply pass the flattened string data structure and the 2nd test will pass as it is the binary table that I generated from the flattened string.

  Thank you

  Pete

  crossrulz is correct.  The Null character affects how TestStand handles the string.  You will need to specify the string to a binary string in the list of settings both the VI.  TestStand then encodes the stringso it can prevent the loss of data.

  If you need work on the binary string in TestStand, you will need to convert it to an array of raw data with PropertyObject.GetValBinary.

  

• Local property node on the VI Analyzer VS variable

  Hi I'm preparing my review of CLD. I had this problem...

  I learned that there are two methods to update the icon on front panel using the value of the variable local node and property

  It is not a good method to update an indicator using these, but if we want to update a control, then there is no choice...

  CLD NOR recommend using the property instead of the local variable node, but when I run my code on the VI Analyzer he created an event

  believing that it is better to use a local variable for good performance...

  ???????

  Yes, the text is correct. Property nodes are useful to access things like visibility and string [] in the control of the ring, but for the value, it is much slower than a local variable.

  One of the advantages is that there wired error so you can force the data stream, and given that the nodes property are executed in order, you can use a property expanded node to find out what order things occur, especially compared to a free local and free property node, in which case you would be forced to use a sequence structure where ofc is a bad solution.

  /Y

• By the way the local variable to a default module

  I use LV 8.6 and TS 4.1.

  I made a custom step Type where I specified a default Module to run and I created a substep VI Edit that the user can move the entry to the default maodule.

  If I pass a value it is working properly. So, I want to pass a local variable, so I have a button in the edict Vi, which displays the property browser dialog box I get the name of the selected local variable. How can I pass the local variable to the default input module? (The value of the local variable is installed during the execution of the sequence).

  Thank you.

  Max.

  Hello

  Yes, I see what your problem is.

  If I am proving a means of suppling a variable as a fixed value or a search string then in my step type I organize the property as a container that contains two properties, one to hold the value and one the search string.

  If you don't have what it takes to change your step types, then you must indicate another to contain this search string, IE a local / fileglobal / global station. Or store it in the memory of your labview. None of them are ideal, as it is best to keep the properties of the step in the step.

  Concerning

  Ray Farmer

• Initialize controls/indicators: invoke node-local variables Vales. Which is faster?

  Hi all

  I would like to get the opinion of the people. This thought just happened for me while I was reading some materials the other day.

  And I have not found any topic which talks specifically about speed after searching the forum.

  It is faster to initialize your controls/indicators using Invoke node OR write directly to the initial value of your local variables?

  From my experience (not large), I have always used the invoke node to initialize controls or indicators.

  But when I but this question, I did a simple reference point and it seems the local variable approach is faster, especially

  If you have the large number of orders/lights to initialize.

  Am I missing something here? The invoke node running something that writing a value of local variable would not do?

  I thought since you need to set the initial state by default for the node to invoke anyway, why not just write the desired initial value

  your local variables?

  I would appreciate if someone can express his own opinion based on their experience and knowledge.

  Thank you ~ ~

  I may need another Cup of coffee this morning, you are in fact callling the reset by default on each individual control.  My last despises, it is that you use the default method Vals.Reinitialize VI all failing.  It will probably be a bit faster than the method on individual controls.  Still not instant, if.

  Are a few msec is worth to you?  If so and you consider the local path, my advice is to group as many controls as possible into clusters for minimize you headaches.