Multiple events structures for same control

Hi,
I would like to use a same blinking button into 2 event structures seperately.
Please see my VI, after the first event is done, the second event is not wait for user to press the button, and it is auto triggered.
How to solve that? Is there any way to reset the event?
Thanks.
Attachments:
2 events.vi ‏13 KB

It is also not clear what you are trying to do with the blinking. In your code, the LED will blink basically always. (you don't use the timeout event).
In the first frame, blinking is enabled. Nothing happens in the second frame until the start event occurs. At this time blinking gets disable for about a nanosecond and gets immediately enabled again in the third frame. Even if the second eveng would not execute, you'll never see a difference. So what's the point?
Here's a quick draft where each press of the start button toggles between blinking and not blinking. Maybe it can give you some ideas.
LabVIEW Champion . Do more with less code and in less time .
Attachments:
2 eventsMOD.vi ‏10 KB

Similar Messages

Can I have multiple event structures with the same event cases?

Hello,
I'm doing an application that reproduces the front panel of the HP6675A power supply. To achieve this, I have done a state machine with different states
(initialize, measures, voltage, current, ocp, ov, store, recall, etc). In each state, should have an event structure that catches the events of the buttons, like for example: if the current state is the Voltage mode and the user press the current button the next state will be the Current mode. For this in each state of the state machine should be the same event structure with the same events.
My problem is that the Vi doesn't work properly when I have multiple event structures with the same event cases. There are some possibily to do this, and how? Or is impossible to have multiple events? I have been reading some posts, but I don't find solutions.
Any help is appreciated.
Thank you very much.
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natasftw wrote:
Or as others mentioned, make two parallel loops. In one loop, have your state machine. In the other, have just the Event Handler. Pass the events from the handler to the state machine by way of queues.
A proper state machine will not need the second loop. The "Wait For Event" or "Idle" state (whatever you want to call it) is all you really need in order to catch the user button presses. The setup is almost there. Maybe add a shift register to keep track of which state to go to in the case of a timeout on the Event Structure.
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Using multiple events structure inside state machine to control the Tab

Hi y'all,
Anne here.I have a Tab indicator in my front panel and I want to be able to control the flow of my program based on what controls I clicked inside the tab. I am using a state machine architecture and inside every state, I use an event structure to check for user interaction to determine the next state and what tab page is going to be displayed next. This means that I am actually using multiple event structures in my application and I use them in just one while loop, but just that they are not running in parallel since I am only using "one event structure per state" which means that only one event structure is running at one time. My questions is, programming technique wise, am I doing it correctly? So far, I am not facing any problem (I am still in the early stage of the project) but I want to check with you all first on your opinion regarding this architecture. Will there be any issue on using multiple event structures in a vi? Since I will be using a tab, and the controls available in the tab will be the controls that will control my event structure for that state, by right, there should be no issue. Am I correct to assume this? Is there any limit on the use of event structures? I have attached here a simple sample of the architecture that I am talking about for your reference. I have attached a 2010 version and a 8.6 version. Let me know what you think or any opinions that you may have.
Hoping to hear from you soon! Thanks so much in advance!
Cheers!
Anne
Attachments:
State Machine-Event Structure Sample_2010.vi ‏19 KB
State Machine-Event Structure Sample_8.5.vi ‏25 KB

Hi jak888,
I decided to use tabs cause I don't want to have subvi pop ups every time i need to perform the process in the state and show an update in the front panel. This is actually going to be more of an ATE where you will have to choose first whether the one using is the operator or the engineer. If the operator is logged in, she will proceed to choose what test to run (this state will have its own event structure). This part, I don't want a pop up, so what happens is that from Login page, if the user logs in as operator, the tab will automatically switch to the Test Selection page. After selecting the test, it will proceed to Start Test state and the tab will show the Result Summary page. If the user logs in as engineer, then a totally different tab will be automatically shown next and so on. By doing this, I will be able to show an update on the front panel objects without having the subvis pop up. I will also just need to use the call reference functions to call my subvis, making my Main VI more generic. The tab Page header will be hidden so the operator will actually not see that there is a tab and that there are a lot of controls and indicators cause they are hidden in the tabs and that page will only be shown based on what they selected from the main tab.
I appreciate your thoughts! thanks so much!

Multiple event structures in one VI

I have two event structures in a single VI, one that handles events that freeze the user interface and one for events that don't. The latter group are all triggered acquisition tasks, where you arm the data acquisition, but possibly might want to abort it (or do other things, while waiting for the data to come. Obviously you need a stop button to be active and responsive. In retrospect, using two loops was possibly a poor choice, but one I made because it never occured to me that these things would only fire once and have to be put in a while loop to be kept active. No other language does that as far as I know. Anyway, the question is how do I keep both active? Do I enclose both in a single while loop? Do I give each there own while loop. Do I give up and merge the two event structures into one. For clarity I would like to keep them seperate, but that is not essential. I'ld like to know what my options are.
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rossu wrote:
If they are in sperate while loops will they both run. If they are in one loop will the loop recycle if one structue is still waiting for an event to occur?
The answer to this is fundamental to how LabVIEW works. A loop will not proceed to the next cycle until everything inside it completes. If you have two event structures in the same loop, both of them need to process an event (or a timeout) before the loop will iterate.
You can have multiple event structures in the same VI.
By "freeze the UI," do you mean the "Lock front panel..." checkbox in the event dialog? There is no problem with having some events that do lock the front panel and some that do not in the same event structure. I'm not sure that this is what you mean by "freezing" the UI, though.
EDIT: and one more comment. Generally you should not put long-running tasks (like data acquisition) inside an event structure. Instead, the event case should pass those tasks off to a separate loop (for example using a queue) so that the event structure can quickly go back to listening for other events.

Multiple event structure in a while loop

Dear All,
               I had a multiple event structure inside a while loop. The purpose of doing so is because I had a few 2D picture on the front panel. I would like to detect which 2D pictures had been click using the mouse down event structure for 8 of my 2D pictures.
              The problem that I faced now is that when I of the event case or one of the 2D pictures had been click, it will not exit the while loop. I had to click on all the 8 2D pictures before it will exit the loop.
              I had uncheck the under the "Edit Event" --> "Lock Front Panel (defer processing of user action) until this event case completes". But I am still stuck inside the loop.
              Each 2D picture will perform different action therefore I cannot have an event case of all 2D pictures inside else I would know which 2D picture had been click.
             Is there any other way out of this situation? Pls help. Thanks a lot

A producer/consumer architecture (look at the examples that ship with LabVIEW) is comprised of two parallel while loops. One loop contains the event structure. The other contains your consumer which is basically a queued state machine. It receives messages from the producer via a queue. Your event structure can register a separate event for each 2D picture control or it can use a single event that would determine which spefic controls was clicked on. This is a more general approach and expands easily. Here is a basic example of what I am talking about.
Mark Yedinak
"Does anyone know where the love of God goes when the waves turn the minutes to hours?"
Wreck of the Edmund Fitzgerald - Gordon Lightfoot
Attachments:
Event Producer-Consumer.vi ‏14 KB

Multiple tax lines for same item

Hi,
Is it possible to have multiple tax lines for same item in an invoice in AR.
Business Need - A few items have multiple tax applicable ( e.g. VAT, Service tax, etc ). And for regulatory purpose customer wants to show each tax separately.
please Advise.
thanks,
K

Hi Hikumar,
With tax groups you have what is called compound taxes.
A tax group is consisted of more than one tax codes and these tax codes may be related or not to each other,you can also specify the precedence of the tax codes in a tax group.
On the Invoice or order item line, the tax group code is entered and the tax engine calculates the tax for each tax code that belongs to the tax group.
If the user wants to see the taxes of this line he will see detailed the tax amounts and rates of each tax code that belong to this group.
In my case i have used a tax group with 3 tax codes with the structure:
Item line amount 1000
1)The first line is a specific sales tax(12%) with taxable basis the amount of the item line=1000*12%=120
2)The second line is a VAT(23%) tax with taxable basis the amount calculated from the first tax of the group=120*23%=27,6
3) The third line is a VAT(23%) tax with taxable basis the amount of the item line=1000*23%=230
For each item line that has the above tax group, the system creates three seperate tax lines
Your case does not seem so complicate as mine.
You can find more information on the AR user guide and the Oracle receivables tax manual.
On which Ebs version are you working on?
If you sent me more detailed you requirement i can quide you on the way to implement it and test it.
I hope this helps.
Regards
Olga

Multiple reconcillation accounts for same vendor

All SAP Gurus,
Is it possible to have Multiple reconcillation accounts for same vendor code (where purchasing org and company code is same)?
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hi,
You can't have more than one because the reconcilation account...Because this is the soul account by which you pay to vendor and send the details to further process to FI dept...
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Event structures for dummies

After all the great help with data handling, I thought I would ask a question about event structures.
I have a main VI that sits around and lets me read in files and change variables. Once I am happy, I press start which fires up some sub VI that start running in the background. I have tried this using event structures. But then disaster strikes!! One of my variables is wrong and I need to stop/reset the sub VIs (without stopping the main program). However, my subVI is running in a timed loop continuously, within the event structure, so it's stuck. Attached is a very simplified VI of what I mean.
I basically want to run a program, set up some variables, set off a background subVI, update/reset if needs be and then press the big continue button to the next stage whilst the subVI is still chugging.
Any suggestions from the Guru's? I do not think event structures are the way forward
"When I read about the horrors of drinking, I gave up reading"
Attachments:
event structures for idiots.vi ‏90 KB

The important thing about event structures is to use them in the right way. For example as a rule of thumb, don't put into an event handler anything that will take more than about 200 msec or so to complete. Why? Studies have shown that 200 msec is the longest delay you can generate without the user noticing the delay (obviously YMMV).
One good solution (as corys pointed out) is the Producer/Consumer Loop - but there are a variety of others. For example, I have created applications where pressing a button launched a long task as a separate process running in the background. When it finished it passed data back to the GUI using another event, queue or some other mechanism.
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
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Invoice request based on multiple sales order for same customer

Hi Team,
I just wanted to know if we can create manual invoice request based on multiple sales order for same customer?
For project based invoice request i have create based on single invoice request.
Appreciate your input here.
Thanks,
Nitin

Dear Ratish,
Thanks for yr reply.
I already did that but it is not serving business purpose.
Comm payment - comes diff time than sales payment.
so ,I will post one entry customer will get hit with total amount Sales + commission
like below
Let say 10, 000 is the sales value and 500 is the commission
So , This entry will get posted
Customer Db- 10,500
Sales Cr- 10,000
Comm Income Cr- 500
But, As I said sales amt will be paid before so We need to clear it partially and some time customer pays also diff amount due to some defect.
So, We wont be knowing for which case we have or havnet received the payment against commission.
As , Customer account is got hit with total amount( Sales+ Comm..value).
Pls advise how to solve this.
Regards,
Sukh

How can I use the same event case for different controls dynamically

OS: Linux 2.6.24-1-686 #1 SMP Sat Apr 19 00:37:55 UTC 2008 i686 GNU/Linux
LabVIEW: Version 8.2
I have a lot of (about 50) controls (numeric, boolean) on my front panel. If a "Value Change" event will be fired by any of them the same event case shall be executed. As I do not want to add all 50 controls to the same event case manually I am looking for a way to do it at run time. Additionally the VI is still under contruction, i.e. controls will be added and removed.
Thanks for any help here.
Regards,
Johannes
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Hi Johannes,
collect all your control references (you can use the FP property for it) and create a user event. Connect this user event to your event structure. Now you have one event case for all your controls. See the attached picture.
Mike
Attachments:
Unbenannt1.PNG ‏11 KB

I using an event structure for an input box and also for hardware input

Hi there!
I have many input boxes and display boxes on my user interface and i have a case for it in the event structure. If the user changes the values of the input boxes, the particular event case writes this new value to the hardware. However, in the timeout section of the event structure, we read the inputs from the hardware and we set the value for its related display object. Within the timeout section i set the value for the related user interface display component, by making use of the property node value.
Furthermore, for most of the display components, i have a event case for a value change associated with it. In that event case, i check for range errors and so forth.
My assumption was that when i read the value in from the hardware and set the property node value, the user interface component's value will change and it would then trigger the event of the value changed for that component.
My assumption worked to the point of updating the component's value, however, it did not trigger the event for the value changed for this component.
Please advise me on how to achieve what i wish to.
Thanks.
Regards,

Local variables are actually much more efficient than property nodes as far as execution speed goes. Take that same VI and delete the property node and instead write to a local variable inside the loop. You'll see the speed nearly identical to writing directly to the indicator. But note that variables also cause a copy of the data to be created. So if you're just using the "Value" property, you're much better off using a local variable. But don't use both at the same time. If you are reading/writing other properties when you update/read the value, you might as well use the value property.
Sometimes you can't get around using either variables or property nodes. Initializing controls to saved values from an ini file is one example. But in this case, they are only written to once as the application starts so the performance hit is negligible.
One thing you can do is store values in a shift register as they are read and pass this through your application so the last value read can be accessed from anywhere. You can even create a cluster that runs through the shift register to hold several values in a single register. This can be expanded a bit farther to create what's called a Functional Global. This basically a subVI with a While loop that only runs once on each call. It has a shift register to store data and a Case structure to Read or Write data into the register. There's a pretty good example that ships with LabVIEW showing how these work. Open the Example finder and search for "Functional Global Communication". This example shows how to use them to pass data between two independent loops, but they work just as well in a single loop application.
One of the big advantages of these Functional Globals over the standard LabVIEW Globals and local variables is that you can add cases to manipulate the data in addition to just storing it. Also, since it's a subVI, access to the data is protected to one caller at a time whereas variables can have multiple reads and/or writes at the same time. This can cause race conditions.
Hope that helps a bit.
Ed
Ed Dickens - Certified LabVIEW Architect - DISTek Integration, Inc. - NI Certified Alliance Partner
Using the Abort button to stop your VI is like using a tree to stop your car. It works, but there may be consequences.

How to stop While Loop in Event Structure with same button?

Hello,
I have a problem. I want to use one control to activate an event in a event structure, and the same control to terminate a while loop in that event.
It is possible to use 2 controls to do this, but I need it to be only one.
Thank you
Message Edited by Heinen on 02-19-2009 06:16 AM
Message Edited by Heinen on 02-19-2009 06:20 AM
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Hello,
I have a bit different problem.
I have a tab control, with several buttons on different pages.
In the current situation, we can talk about two pages, where one page ("Settings") in the Image, has a START and EXIT button, while second page ("Wait") has an EXIT button.
In a while loop, I have event structure, which handles events of the START and EXIT buttons of the Settings page. This is fine. But I also want to control the Exit button of the Wait page.
The control works like this:
When I click on Start in the Settings page, the front panel shows Wait page and attempts to connect to a datasocket server on the remote computer. If the user wants to stop this process, he can click on Exit on Wait page too. But, this doesn't give any immediate effect. On the even of Start button, the front panel is not locked, so the user can actually click the Exit button on the next page when it's visible. But it's of no immediate effect. Means, what the LabVIEW does is, finishes the execution of event in Start button's click, and while this executes, it doesn't consider the Exit button's refreshed value (shown in Red circle in the block diagram).
Simple question: Is there any way to check the updated (latest/live) value of a control during some event's execution? Or if I write an Event "Value Changed" for the Exit button and pass it to some variable. Is it the only solution?
Thanks ahead.
Vaibhav
Attachments:
terminate event_diagram.jpg ‏200 KB
terminate event_front_1.jpg ‏63 KB
terminate event_front_2.jpg ‏63 KB

How to handle event structures for two buttons and two counters.

     *I have two buttons A and B, and have to compare the difference in hits between them. So do I place an event structure within a while loop for each button (2 buttons, 2 event structures, 2 while loops), or does it need to be one event structure with cases for both buttons whithin one while loop?
     *How do I pass the values of buttons A and B's hit counters out of the while loop in order to calculate the differences between them after each increment, not just the final count after the stop button is hit?
    *How would I make one stop button work to handle both buttons A and B?   I tried to place the actual stop button in one button A's structure and its global in B's structure, but It wont seem to let me use a local variable for a latchable control
Checker

You should probably have not started a new thread and waited until your question in the original thread was answered. You can modify altenbach's example for a second button. You have a single event structure with a new event for the second button. You have a second shift register to track the number of times the second button is pressed. Inside the while loop but outside the event structure, you just have a subtract function in or to report the difference. do not modify the posted example for the stop button. It works perfectly as is.

Multiple event structures in one program

I know it's not good practice to have one event structure inside another event structure (I don't know exactly why). But if another event structure is in the subvi, is it safe? Please comment.

guangdew1 wrote:
I know it's not good practice to have one event structure inside another event structure (I don't know exactly why).
This is because of dataflow and the way event structures work. If you have an event structure inside an event structure, both event structures will accumulate events whenever one occurs, but it is unlikely that they can be handled in the order they occur or at all. By default, event structure are set to lock the front panel until the event completes, meaning that if an inner event gets triggered first, the code will lock up, because it will no longer be possible to trigger one of the outer events. If the outer event occurs first, it cannot complete, because it requires a later firing of one of the inner events before it is ready to handle the next event that occurs in the UI. Even if it marginally works if the panels don't get locked, you are requiring the user to trigger events in a certain order. How is he supposed to know what's allowed or not?
If this is not exactly clear to you, you need to start with a few tutorial and learn about dataflow, Then start using a single event structure and see how things work by programming scenarios and see what happens.
guangdew1 wrote:
But if another event structure is in the subvi, is it safe? Please comment.
Event structures are only useful inside interactive subVIs that show their front panel. even then I strongly advise against calling anything interactive, or anything that takes excessively long, inside a main event structure. You end up with code that can become unpredictable, can deadlock, is hard to debug and flies in the face of all good programming guidelines.
Obviously, you have some specific application in mind where you think something like that is useful, I can guarantee you that there is a much better solution is you think about this a bit longer. If you need help, please describe exactly what the program should do and how it should react to user interactions at the various stages.
A program should always be approached from the code and UI needs. Don't start with a harebrained code construct (events inside events) and then look for a use. It does not exist!
Event structure only belong in toplevel loops. They should never be hidden insde squences or case structures (or other event structures as already mentioned above). If you have multiple toplevel loops that run in parallel, it is safe to place up to one event structure inside each. Each event structure can have an unlimited number of event cases. This should be sufficient to handle any programming need you might have.
LabVIEW Champion . Do more with less code and in less time .

Basic structure for sequencial control

Dear all,
I'm trying to create a vi to realize sequencial execution of subvi's, the time delay between two subvi's should also be controllable. Is there any sample program available? Thanks
Jerry

Also look under the Help menu, find examples. and search for State Machine
There are empty templates available if you look under the Files Menu, select New > From Template>
You'll see a list, such as Event Structure, with data, etc and State Machine. There should be 2 of them.
As Altenbach suggested, do a search in this forum for State Machines.
They are easy to implement, easy to use, easy to maintain, and are scalable. Use Type Def'ed control for your case selector, you'll thank me after you modify it's content for the 10th time
RayR

Multiple events structures for same control

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