Dataflow Conflict appearing on the front panel
Hello,
my vi is almost done but I still have a problem with the front panel. I think it's about data flow conflicts in my vi.
When you run my vi, you will see the pop-up window to ask you about putting a file path, adjusting the units, selecting data to save and plot. Then you might want to change the units, turn on-off all light and ok buttons to choose which data you want to save. Then click RUN.
The problem is; supposedly all buttons are on as default, if you turn off some saving or plotting buttons for not choosing to save, then click RUN, after that all buttons are on again even though you turned them off before running. They should stay off if you didn't select to save them. The condition of the main data stream always goes back to be the same before running (only light and ok buttons).
Do you have any ideas how to solve this problem?
Thank you in advance
Solved!
Go to Solution.
Attachments:
Value Measurement Project.lvproj 2 KB
You have what's called a race condition which commonly creeps into programs that use local variables. If you look at your first while loop you read in the current "Main Data Steam" value from the control and store it in a shift register. After the event structure exits you write the value from this shift register back into the control and in the process overwrite any changes the user may have made.
One quick and dirty solution would be to handle the Value Changed event for "Main Data Stream" in your event structure to update the shift register whenever the user changes values in the control.
A better solution would be to get rid of the shift registers and move the local variables into the event structure. As long as the "lock front panel until event completes" option (I'm not sure of the exact wording and I'm working in LabVIEW Base at the moment so I can't check it) is selected it will ensure that you don't run into a race condition (you know the value can't change inbetween you reading in the value and you updating the control).
Better yet would be to avoid local variables wherever possible. This is just general advice and not something I can make much more tangible without knowing the details of how you want your application to behave.
Hope this helps,
Simon
Similar Messages
-
How to find VI's connected terminals when controls are hidden on the front panel?
When working with a sub-VI which has terminals connected to hidden controls is there a straight-forward way to find the terminals on the block diagram?
I click on the terminal and an outline appears on the front panel but when I try to click on that outline I can not unhide the control.
The only way I have discovered to find the terminal of the connected control is just check each terminal on the block diagram which looks like it might be connected.
I'm using LV7.1 but also use 8.5.
Thanks,
DaveyBen wrote:
smercurio_fc wrote:
If I understood the premise of the question it sounds like you have controls/indicators wired to the VI connector pane, but for some reason these controls/indicators are hidden. If this is a VI you wrote slap yourself. If this is a VI someone else wrote, go slap them.
One way that you can find the terminals on the block diagram by performing a search by text. The context help will show you the names of the controls/indicators. The only problem with this approach is that if the control/indicator has the caption visible rather than the label, then the context help will show the caption, not the label.
Another method is to use scripting. Not sure if it's worth the effort for just one VI, though.
Before we get all slap-happy I have to ask...
If I have a sub-VI which is set for Print on completion and the controls in/out for the icon connector are NOT supposed to show up on the final report, isn't setting those objects as hidden a viable option?
Ben
Well, of course, Ben. My comment was not meant to be taken seriously... hence the smiley happy icon. To respond to your question in a more serious matter, though, there's always exceptions to rules. That's why they're rules - they're meant to be broken. Otherwise they wouldn't be rules. It's a strange state of the universe, isn't it? Although, one could probably just place the control behind another object. That sort of hides it, doesn't it? -
Not able to get resource names on the front panel
Hi,
I tried communicating with Agilent DMM (34405A) with USB interface using Labview 8.5. I have installed Agileni IO Libraries Suite 14.2 and NI Visa 4.2. I have downloaded and installed Labview drivers for Agilent 34405A. The instrument is visible in Agilent Visa Assistant and also in NI MAX. But the problem is that, the resource name doesnot appear on the front panel. I have enabled tulip passport.
rgds
BalkiSwathiHi Vijay,
The Goal Diagram Statuses are calculated for the latest date of the underlying PAS model. If you are not seing any status in the Goal Diagram (and the properties are set like Bob mentions in his post above), you might want to check if you have values in PAS for the date that is set as latest. If this is not the date for which you want to see your scorecard, you can change it directly in PAS.
You can force the application to re-calculate the Goal Diagram Statuses by going to the Admin Interface and save again the settings for any KPI in the respective context. This simple step deletes the existing statuses and forces the application to re-calculate them the next time you enter the end-user interface.
If you have data for the PAS model latest date, and you performed the step above to force the application to re-calculate the statuses, and still they are not showing, you should then create a message in the SAP ServiceMarketplace.
Best regards,
Ricardo -
How to synchronize presentation on the front panel to the start of a 75Hz monitor's retrace cycle?
How to synchronize front panel presentation with the start of a retrace cycle of a 75Hz Monitor, so when a bitmap is presented 100ms, its duration is indeed 100ms on the monitor?
Hi,
In the old days (late 90's), we used in port and out port to wait for
vertical retraces (or even horizontal retraces).
I searched the web (vertical retrace), and there seem to be lots of
infromation and tools, like
http://www.compuphase.com/vretrace.htm
It uses a simple routine:
mov dx, 3dah ; VGA input status register
vretrace_loop:
in al, dx
test al, 8 ; bit 3 set?
jz vretrace_loop ; no, continue waiting
But to get it working, you need a VxD. Good news is you can download it.
The also suggest you use WaitForVerticalBlank(), but dx could be hard to get
working under LabVIEW.
Please let us know how (and if) you got it working with LabVIEW!
Regards,
Wiebe.
"Vinci HK" wrote in message
news:[email protected]...
> Hi Robert,
> I am so excited to have received a response! Sorry that I didn't reply
> earlier as I have been out of town. You are understanding the problem,
> so good!
>
> I just want to know the exact duration a stimuli in the front panel is
> presented. I can make it to last for 13 frames, but the problem is to
> ask LabView to synchronize with the start of a frame.
>
> The crucial thing is that I want a trial of presenting 700ms blank
> screen + 1300ms bitmap will add up to 2000ms on the front panel. And
> in the next 2000ms, a different bitmap will be used for the 1300ms.
> The start of a trial is initiated by a pulse from the parallel port. I
> need the 2000ms on the front panel to be really 2000ms+/-5ms.
>
> My worry is that even if I buy the external clock and the RealTime
> system of LabView, I won't be able to get the front panel to
> synchronise with the refresh cycle of the monitor, so that the trial
> length as it appears on the front panel is 2000ms +/- 5ms.
>
> What do u think?
>
> I am using LabView for my fMRI experiment, and I wonder if you know
> anyone from the fMRI community who are using LabView for stimulus
> presentation and synchronization with MRI data acquisition?
>
> Thanks,
> Vinci -
Load a VI in the front panel of another VI
When the first VI runs I would like the other VI appear in the front panel of the first VI with all its components.I don;t want to have two windows, just one.
I am pretty sure that this is not possible, yet. It should be possible with ActiveX, but there is no implementation yet.
-Jim -
Having several windows appear ...
Hi,
You can't create several windows for one VI. But you can use the "Tab Control" and change tab's in the program. Or you can use sub VI's and show ther front panels.
To show the front panel of a sub VI you have to open the VI you want to show and select "File->VI Properties". In the VI Properties window select Category "Window Appearance" and click Customize...
In the Customize Window Appearence window, here you can set a number of attributes for how the window will appear, select "Show front panel when called" and "Close afterwards if originally closed" click OK and OK and save the VI, done.
Now the VI front panel will appear then you use it as a sub VI.
/Thomas -
How do I get the Label for a Front Panel Control to appear in the Block Diagram but not on the Front Panel? On the Front Panel I am making a complex control that consists of a Slider and a Numerical Input box. Both Controls display the same information and either can be used for Input. When one changs, the other is made to display the same value.
But I only want the Slider to display the Label on the Front Panel, to avoid confusion. On the Block Diagram however, I want both controls to display their Labels so that I know what they are. How do I display the Label for a Control on the Block diagram, but not display its Label on the Front Panel?No. The Label Visible property is separate for the front panel control label and the block diagram terminal label.
How did you start out with the block diagram's label not being visible? Whenever I drop a control or indicator, the label is always visible on both the FP and BD by default. Maybe there is a LabVIEW option that causes new controls/indicators not to have their labels visible by default, but I have yet to find it. I don't think an item should ever be dropped without the label visible, good LabVIEW coding practice demands that the labels for control terminals on the block diagram be visible so that you know what control or indicator a wire is going to.
That being said, I have seen a lot of VI's posted where the label for the terminal on the BD is not shown (against good programming practice.) I've gone to the BD and right clicked to show the label. Sometimes, the people have an empty label (which will turn off the visibility for both the FP and BD) and I'm forced to add some text of my own into the label so I can figure out what their code is doing. When I add some text to the label, at that time, I find both the BD and FP labels become visible.
Are you dealing with controls that have empty labels to start?
Good programming practices:
1. Always have a name for all of your controls, never use and empty label by deleting the text in the label.
2. Make the labels unique. For example, don't have two controls both called Stop. How do you know quickly know which terminal relates to which control?
3. Always show the labels on the block diagram, so you know the function of a control's terminal. If you want to hide the label on the FP, that's okay.
4. If you want a different label to appear on the FP than whatever you actually called the control, then use the caption. You can hide the label and show the caption. This is useful if you need to programmatically change what the "label" is on the front panel such if you are making an application that needs to change its user interface such as for a foreign language. -
I can successfully view and control a VI remotly. However, the remote VI dinamically loads another VI, this VI loaded dinamically is a VI that allows open others VIs, I want to see the files that contains the server machine, in the client machine, but the front panel of the dinamic VI appears only on the server and not on the client, How can I display the fron panel with the files of the server machine of the dinamically loaded VI on the client computer?
Attachments:
micliente.llb 183 KB
miservidor.llb 186 KB
rdsubvis.llb 214 KBI down loaded your files but could use some instructions on what needs run.
It seems that you are so close yet so far. You need to get the data on the server machine over to the client. I generally do this by doing a call by reference (on the client machine) of a VI that is served by the server. THe VI that executes on the server should pass the data you want to diplay via one of its output terminals. You can simply wire from this terminal (back on the client again) to an indicator of your choosing.
Now theorectically, I do not think that there is anything that prevents use from getting the control refnum of the actual indicator (on the server) of the indicator that has the data, and read its "Value" using a property node. I have never tried this idea but it seems t
hat all of the parts are there. You will need to know the name of the VI that holds the data as well as the indicator's name. You will also have to serve all VI's. This is not a good idea.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction -
What should I do if I want to display on the front panel in real time the values from Polarizer #, P1, P2 and the last calculated value (P2/P1 * 100) called T% in a table or some graphical representation like that? What would I have to do? It could just be Polarizer # and T% if that would be simpler. I just want to let the user know the values in a list, spreadsheet or table as they go. One last thing is that I would like to be able to stop the program at any point in time as soon as the stop button is pressed. As of now, when the button is pressed it goes through the iteration currently in progress and then one afterwards. I want the program to end as soon as the stop button is pressed no matter what sequence it is. What can I do to achieve this? Could you give me an example or modify my program to show me this.
Thanks,
Steve
Stephen Coward
Northrop Grumman
[email protected]
Attachments:
EPM2000 almost done.vi 50 KBPut a single frame sequence structure around your stop button and then wire from the error cluster going into the error handler to the edge of the sequence structure. Now your code will stop at the end of the current iteration. To see why this works, watch you code execute with execution highlighting turned on and review the section of the manual talking about "Dataflow".
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps -
Show 30 different channels without getting the front panel too crowded
What function should I use to receive the data of 30 channels without getting the front panel crowded? I´ve already done 30 controls simulating the multiplexer in the front panel, but how can I choose each channel in a way that the data from only this channel appear as I click in that control in the panel, and I can change that as I want during the acquisition.
jvzs wrote:
I´ve already done 30 controls simulating the multiplexer in the front panel, but how can I choose each channel in a way that the data from only this channel appear as I click in that control in the panel, and I can change that as I want during the acquisition.
Instead of 30 controls, always use an array of controls. This often simplifies the code dramatically. For example, here's a quick rewrite of Randall Pursley's example above using arrays (LV 8.0). The code is about 10x simpler.
LabVIEW Champion . Do more with less code and in less time .
Attachments:
Select_DisplayMOD.vi 41 KB -
Hi Everyone,
The simulations that I am creating are very simple themselves but are intended for use in a classroom setting to help students learn more about the theory being demonstrated. I am hoping to be able to place a "Help" or "more info" button on the front panel so that if a student wants more info about the theory they can click on it and a pop up appears with background info on it. It should also have a second button to close it and return to the main front panel again. Can anyone lead me in the right direction?
Thank you!
Solved!
Go to Solution.Use an event structure on the main vi that when the button is clicked, launches a "Help" sub vi. Inside the sub vi (with the properties set to load front panel when called of course), use another event structure to wait for the button of the subVI to be clicked so you can return to the main VI. Do you need help with using event structures?
Charles
Charles Chickering
Architecture is art with rules.
...and the rules are more like guidelines -
Is there a trick get around physical bundling of items on the front panel?
Ok - so I appreciate how bundling items on the front panel into a cluster can make the programmatic code very slick and easy to access.
I know this is completely obvious - but it forces me to arrange my front panel objects I would prefer not to arrange them. Here's why: I have my objects grouped together in a manner that reduces the number of datasocket read/write necessary for VIs to intercommunicate - they are grouped based on how they should be communicated to other VIs - not based on their physical arrangement on the front panel.
It seems the only way I can organize my objects into a cluster that appears as a pink control/indicator block in my diagram is by assembling
the objects into a cluster on the front panel... and this pink block is very useful as I can make local variables for it. This is much simpler than having all the controls and indicators bundled into a cluster for network transfer... but still having to use local variables for each control/indicator in order to use it elsewhere in the diagram.
Ugh. I fear this message is too much rambling and not enough information for anyone to help me... I'm going to post it in the hopes that someone can follow me.
I guess before I submit this I should remind you of what I was hoping to accomplish - to use the front panel to group objects but then skirt the requirement of keeping this objects in the same physical cluster box on the front panel.
again, ugh,
JimPlace all your front panel objects the way you want them then in the block
diagram use the Bundle by Name vi to create a cluster.
Kelly
"dingler44" wrote in message
news:[email protected]..
> Ok - so I appreciate how bundling items on the front panel into a
> cluster can make the programmatic code very slick and easy to access.
> I know this is completely obvious - but it forces me to arrange my
> front panel objects I would prefer not to arrange them. Here's why: I
> have my objects grouped together in a manner that reduces the number
> of datasocket read/write necessary for VIs to intercommunicate - they
> are grouped based on how they should be communicated to other VIs -
> not based on their physical arrangemen
t on the front panel.
> It seems the only way I can organize my objects into a cluster that
> appears as a pink control/indicator block in my diagram is by
> assembling the objects into a cluster on the front panel... and this
> pink block is very useful as I can make local variables for it. This
> is much simpler than having all the controls and indicators bundled
> into a cluster for network transfer... but still having to use local
> variables for each control/indicator in order to use it elsewhere in
> the diagram.
> Ugh. I fear this message is too much rambling and not enough
> information for anyone to help me... I'm going to post it in the hopes
> that someone can follow me.
> I guess before I submit this I should remind you of what I was
> hoping to accomplish - to use the front panel to group objects but
> then skirt the requirement of keeping this objects in the same
> physical cluster box on the front panel.
>
> again, ugh,
> Jim
> -
Calling the front panel of a sub.vi
Is there a way to call the front panel of a sub.vi so that as soon as the sub.vi begins to execute, its front panel is displayed?
Solved!
Go to Solution.LarsUlrich wrote:
That link you posted... is that a function I can find from the block diagram somewhere? I'm looking for it but can't seem to find it (also I am running a pretty old labVIEW 8.5) and I have no clue what the "VI methods" class is.
It's a method for a VI reference. You create a reference to a VI (for example, by using the Open VI Reference function), and then connect it to an invoke node. Select the method from the popup list.
The settings in VI properties will probably be fine, but I can't find it either, (there are 12 menu tabs, after all) and it probably isn't labeled as obviously as "open front panel when run." My guess is under "execution," maybe the run when opened selection?
VI Properties -> Window Appearance -> Customize.
EDIT: The method you used applies only to that instance of the subVI. If you have the subVI in several places on your block diagram, then the other instances are not affected. This would be applicable if your subVI is an information dialog or something. -
I have a VI and an attched .txt data file. Now I want to read the data from the .txt file and display it as an array in the front panel. But the result is not right. Any help?
Attachments:
try2.txt 2 KB
read_array.vi 21 KBThe problem is in the delimiters in your text file. By default, Read From Spreadsheet File.vi expects a tab delimited file. You can specify a delimiter (like a space), but Read From Spreadsheet File.vi has a problem with repeated delimiters: if you specify a single space as a delimiter and Read From Spreadsheet File.vi finds two spaces back-to-back, it stops reading that line. Your file (as I got it from your earlier post) is delimited by 4 spaces.
Here are some of your choices to fix your problem.
1. Change the source file to a tab delimited file. Your VI will then run as is.
2. Change the source file to be delimited by a single space (rather than 4), then wire a string constant containing one space to the delimiter input of Read From Spreadsheet File.vi.
3. Wire a string constant containing 4 spaces to the delimiter input of Read From Spreadsheet File.vi. Then your text file will run as is.
Depending on where your text file comes from (see more comments below), I'd vote for choice 1: a tab delimited text file. It's the most common text output of spreadsheet programs.
Comments for choices 1 and 2: Where does the text file come from? Is it automatically generated or manually generated? Will it be generated multiple times or just once? If it's manually generated or generated just once, you can use any text editor to change 4 spaces to a tab or to a single space. Note: if you want to change it to a tab delimited file, you can't enter a tab directly into a box in the search & replace dialog of many programs like notepad, but you can do a cut and paste. Before you start your search and replace (just in the text window of the editor), press tab. A tab character will be entered. Press Shift-LeftArrow (not Backspace) to highlight the tab character. Press Ctrl-X to cut the tab character. Start your search and replace (Ctrl-H in notepad in Windows 2000). Click into the Find What box. Enter four spaces. Click into the Replace With box. Press Ctrl-V to paste the tab character. And another thing: older versions of notepad don't have search and replace. Use any editor or word processor that does. -
I have hidden unwanted books from the purchased area of the iBooks store, but they're are still appearing on the front page of iOS as cloud downloads, is there a way to remove these from iBooks without using the hide iCloud books button?
Let me explain a little more. I had downloaded a lot of free books in the past as a trial when iBooks was first released and since then I have decided I no longer want them, because of this I hid them from the purchased section of the iBooks store. The 5 books left are ones I decided to keep as seen in the following picture.
This is how it appears in iBooks on my mac. There are 4 books downloaded and 1 book that I have decided not to download at this time. I would still like to keep this book available in the cloud incase I want to download it again in the future. You’ll notice that hide iCloud books is not selected, if I wanted to hide the book that I have chosen to keep in the cloud, but have not downloaded yet I could.
This is exactly how I think this feature should work. If you have hidden a book from your purchases it should not show up in the mac Ibooks app. (I am aware you can never actually delete a purchase, just hide them and that hidden purchases can be restored to your account from within the account management section of the iBooks store).
The iOS app is working differently for me. Here is a picture of the purchased tab on the iBooks store in iOS Ibooks. Again notice that pictures of Lilly is still yet to be downloaded. This is how I expected it to look.
If we visit the front page of iOS iBooks the view is very different from what I expected. Here we can see the 4 books I wanted to keep on my device and have downloaded. We can also see the 1 book I wanted to keep, but did not want to store locally on the device and left in iCloud (Pictures of Lilly). However we can also see all the books I had hidden from the purchased section of my iTunes account and which I believe should no-longer be visible, Dracula, frankenstein etc…
I am aware of the hide iCloud books button within the iOS app, but I did not need to use this to hide the books I had removed from the my purchased section of the iBooks store on the mac, why are they still appearing in iOS?
I’m still not sure if this is a software glitch or not. This article suggests to me that books can be hidden, but I had already completed these steps.
https://support.apple.com/en-us/HT201322
A browse of google also suggests people may have been able to hide past purchases from the front page of iBooks on iOS in the past.
In case there was an issue with syncing I tried logging in and out of my iTunes account via settings in iOS. Force closing the app, disabling automatic downloads and removing my device from iTunes in the cloud. Syncing with iTunes on the mac did not correct the issue either.
Interestingly I have the same issue on my iPhone 6 running iOS 8.3 as I do on my iPad mini suggesting that this might be an issue either with my account or with iOS iBooks software in general.
If there is a way to remove the already hidden iBooks in your account from the front page of iBooks on iOS without using the hide iCloud downloads button? Please help community!My apologies for the lack of photos, here is my post again with photos.
I have hidden unwanted books from the purchased area of the iBooks store, but they're are still appearing on the front page of iOS as cloud downloads, is there a way to remove these from iBooks without using the hide iCloud books button?
Let me explain a little more. I had downloaded a lot of free books in the past as a trial when iBooks was first released and since then I have decided I no longer want them, because of this I hid them from the purchased section of the iBooks store. The 5 books left are ones I decided to keep as seen in the following picture.
This is how it appears in iBooks on my mac. There are 4 books downloaded and 1 book that I have decided not to download at this time. I would still like to keep this book available in the cloud incase I want to download it again in the future. You’ll notice that hide iCloud books is not selected, if I wanted to hide the book that I have chosen to keep in the cloud, but have not downloaded yet I could.
This is exactly how I think this feature should work. If you have hidden a book from your purchases it should not show up in the mac Ibooks app. (I am aware you can never actually delete a purchase, just hide them and that hidden purchases can be restored to your account from within the account management section of the iBooks store).
The iOS app is working differently for me. Here is a picture of the purchased tab on the iBooks store in iOS Ibooks. Again notice that pictures of Lilly is still yet to be downloaded. This is how I expected it to look.
If we visit the front page of iOS iBooks the view is very different from what I expected. Here we can see the 4 books I wanted to keep on my device and have downloaded. We can also see the 1 book I wanted to keep, but did not want to store locally on the device and left in iCloud (Pictures of Lilly). However we can also see all the books I had hidden from the purchased section of my iTunes account and which I believe should no-longer be visible, Dracula, frankenstein etc…
I am aware of the hide iCloud books button within the iOS app, but I did not need to use this to hide the books I had removed from the my purchased section of the iBooks store on the mac, why are they still appearing in iOS?
I’m still not sure if this is a software glitch or not. This article suggests to me that books can be hidden, but I had already completed these steps.
https://support.apple.com/en-us/HT201322
A browse of google also suggests people may have been able to hide past purchases from the front page of iBooks on iOS in the past.
In case there was an issue with syncing I tried logging in and out of my iTunes account via settings in iOS. Force closing the app, disabling automatic downloads and removing my device from iTunes in the cloud. Syncing with iTunes on the mac did not correct the issue either.
Interestingly I have the same issue on my iPhone 6 running iOS 8.3 as I do on my iPad mini suggesting that this might be an issue either with my account or with iOS iBooks software in general.
If there is a way to remove the already hidden iBooks in your account from the front page of iBooks on iOS without using the hide iCloud downloads button? Please help community!
iPhone 6, iOS 8.3, Also an issue on my iPad mini iOS 8
Maybe you are looking for
-
Voicemail not working - Callers can't leave messages
Hi, I've had my iPhone a couple of weeks but i've only just realised that my voicemail isn't working. I've done the password set-up and can access my voicemail settings by dialling and holding 1 but people calling my phone do not get the opportunity
-
Or is my device just having issues, and it SHOULD remember me each time? It's too much hassle to go copy out my sync key each time from where I've saved it in the Notes app, so I almost never use FF Home - I just google or try to guess addresses in S
-
After updating ITunes, it, ITunes started loosing my music files and stopped playing more than one song at a time also there would be duplicate songs in the same folders.What now?
-
Purchased Movies burnt to dvd-r/dvd+r won't play in standalone dvd player
My panasonic dmr ex-77 plays all kinds of discs including the above. Having purchased from the ITunes store, making copies of the movies in both types of dvd, both are not recognised by my panasonic dvd player. I have tried others recorded on the pan
-
Using XSLT Transformation to Load Deep Structure
Greetings! I have the need to load data from an XML file into a structure that contains a nested table. I've written the XSLT to load the basic structure but I'm not familiar enough with XSLT to know how to populate the nested table. I've searched