Can I build a XY chart control to define a spline on the front panel

Dear LabView users,
I would like to replace a 2d numeric array control with a XY chart where the users could drag data points on the chart to create the spline of their choice. Is this possible?
best regards
Richard Elliott
Cardiff University

I think you will be better off using an XY graph and events for mouse clicks.
http://sine.ni.com/apps/utf8/niepd_web_display.display_epd4?p_guid=E64297151FA72B7DE034080020E74861

Similar Messages

How can I specify simple math like in a Formula Node but on the front panel?

If the Formula node had a "text" property, that would work for me, because I could limit my inputs and outputs to N floating-point numbers.
LabVIEW once had such a thing but it was in an add-on math library, and I don't remember what it was called.
Solved!
Go to Solution.

Thanks; that led me directly to what I was looking for. A combination of "Parse Formula String.vi" and "Eval Parsed Formula String.vi" works perfectly for me!

Hi. I want to build a GUI based on several windows appearing following a certain sequence. How can i create different windows in the same VI? Also, i want the front panel of a subvi to appear when i run, how can i enable this.Thanks

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

Can i place controls from the properties dialog of an express vi on the front panel?

I'm using the spectral measurements express vi in my vi and I'd like to put the "window" and "number of averages" controls from the properties dialog on the front panel. However, there are not outputs on the express vi icon for these parameters. Can I place controls for these on the front panel somehow or do I always have to go into the block diagram and open the properties dialog to change the values?

The way to do this is to right click on the express VI and select Open Front Panel. This will convert it to a standard subVI. then go into the subVI and replace the Spectrum Averaging and Spectrum Window constants to front panel controls by right click on them. Right click the icon and select Show Connector. Wire the new controls to a free terminal on the connector. You may have to add additional terminals if there aren't any available to wire to the new controls.

How can I make a global change so all controls and indicators labels on the front panel change to another colour?

How can I make a global change so all controls and indicators labels on the front panel change to another colour?
I need to change the front panel so that it can be used in a dark environment.

Hi
The only way I see, is to use the "Controls[]" property and iterate through all of them. But don't forget about nested elements (i.e. clusters, tab-controls, ...).
Thomas
Using LV8.0
Don't be afraid to rate a good answer...

Way to plot two variables on a chart by selecting the two variables on the front panel?

Hello,
I have created a VI to control a tensile tester which controls/outputs the following variables: time, load components in 6 directions, tensile displacements, displacements measured by a capacitance sensor.
Is there a way such that there would be only one plot on the Front Panel, and there will be buttons on the front where I can select the variable for the x and y axis when the program is running?
I only know how to make a plot using Chart Buffer using only two fixed variables. The only way I think of doing this is making a plot for every single permutation of variables, then put those plots in Tab Control...is there an easier way?
Thanks!

I have done this a lot in applications to save realestate and simplify the UI. Basically, I create an enum (or typedef) describing the x or y-axis values I would like to display on a graph. Using an event structure, you can watch for a change in these selector and re-plot your graph. You store your data somewhere (possibly in an array) and simply index into that array based on what you want to show. I attached a short example to illustrate this implemenation. Hope this helps. (LV2009)
-cb
Attachments:
Select from multiple curves and axis to plot.vi ‏19 KB

How can I display the front panel of the dinamically loaded VI on the cliente computer, the VI dinamically loaded contains files, I want to see the files that the server machine has, in the client machine

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 KB

I 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

How can I display a changing variable in a subvi on the front panel of the main vi as the subvi is excuting

In the document attached the vi on the right is sub to the vi on the left. On the subvi on the right the variable "Field Reading" is continuously updated on the front panel of the subvi as the "for" loop is executed, but only the last value of the variable is updated on the main vi front panel which is what is expected. My question is how can I display the changing value of "Field Reading" on the main vi front panel as the "for" loop in the subvi is running?
Thank you.
Solved!
Go to Solution.
Attachments:
Doc2.docx ‏554 KB

Hopefully I can explain it well enough. It really is simple.
1) Create an empty global variable and call it something like User Interface References.vi
2) For each and every control and indicator on your front panel, right-click and select Create/Reference
3) Place these references wherever you like (I use a series of Event cases to perform my initialisation and these all live in one of these event cases). They can be placed anywhere in the main vi.
4) For each of the references, right-click and select Create/Indicator
5) Moving to the front panel, Cut all the indicators and Paste them in the global variable (eg. User Interface References.vi)
6) Moving back to the block diagram, wire the global variable to each of the references and select the same named global variable.
All the hard work is now done (until you add another user interface terminal). You should now have something that look as shown below, [except the reference labels would be to the left (not sure why the snippet put them above)]. In my latest program I have 82 references!
Done. You can now access all your front panel controls and indicators anywhere in your program as shown below.
You can just select Value in most cases, but in this particular case I wanted to fire off an Event to do some things (log the alarm) as well as just update the value. So, this is another bonus with the method.
Hopefully this all makes sense. If not, let me know.

How to get the position of the stem in control valve using slider control in the front panel

I have created a calibration program for a control valve. Signal (4-20mA) is generated from labview using slider contorl which is given to the valve via DAQ(module 9265) and again the feedback signal from the valve is acquired using DAQ(module 9203).. . There is an input ISO/ISC(Increasing signal to open/ Increasing signal to close) in the front panel.
ISO would set the output to increase from (4-20)mA further opening the valve
ISC would set the output to increase from (4-20)mA further closing the valve
I have doubt, how can i get the position of a stem

Ravens Fan wrote:
If the position of the stem is being sent to the PC through a 4-20 mA signal into your DAQ 9203 module, then you just need to do an analog input read in order to get the signal.
When reading this post, that is what came to mind... So let's see if both RavensFan & I are trying to understand the same thing... Are you saying that the position of the stem is linear (or scaled) to the amount of current sent to it? Meaning a 4mA signal would move it a certain distance, and 10mA would move another given / known distance? Or are you saying that it is calibrated so that a 20mA signal for a certain duration (ms) would move it a given distance? So the scale would be time and not current unless a lookup table is used to adjust the time duration based on the current being drawn...
It's just that I am not familiar with solenoid / drive devices that related to current.. To voltage, yes. To time, yes.. To current, I'm simply saying that I am not familiar with that. Can you tell us more about this stem (mfg / model designation)?

Analog output to the DAQ that changes when controls on the front panel change

I'm using the PCI-6024E, and trying to output an analog waveform that can change when one of the two controls on the front panel change. It outputs fine setting it to continuous output and using a simple while loop around the "Is Task Done" VI, but if I put the "Write" VI in the while loop, it doesn't output steadily. I then tried to use an event structure, so that I'd only have to write every time something on the front panel changes, but for some reason it was writing finite samples, even though I set the Timing VI to continuous. I looked around the NI site, and found an article about this with an example. I tried to change it around to use my waveform, but whenever I run it, I get a memory underflow error. Has anyone needed to do this before? Thanks in advance.
-- Josh Matloff

Hi Josh-
It looks like you forgot to post the code still, but I'll take a stab at the problem anyway. It sounds like you're looking for a way to update a continuous waveform at runtime.
You will need to stop the task in order to replace the write buffer information, but this will only be a small gap in operation. I have attached a modified LabVIEW shipping example that shows how to use value change events for any of the pertinent waveform parameters to either programmatically stop the task, replace the buffer, set timing and restart or to just pass the task information straight through. This will lead to continuous operation with no breaks at the output.
Please let us know if this clears up your questions.
Thanks-
Tom W
National Instruments
Attachments:
Cont Gen Voltage Wfm-Int Clk with Runtime Update.vi ‏134 KB

How can I make an area of the front-panel have scroll bars?

I'm writing a VI that provides many options to the user. The front-panel is large and contains many controls ~130 of them, it's divided up visually to match the workings of the system the VI controls. One particular functional block has very many control options though these are rarely used. I can't fit all of the controls I need onto the screen area I have available.
What I would like is a way of making an area of the screen with scroll bars on it. I don't need any more than that, just an expansion of the front-panel area I have available. The "Sub-Panel" feature provides the scroll bars. But, a Sub-Panel is a way of accessing another VI, I don't want to do that. I could put the extra controls on the far-left or far-right of everything else and get the user to scroll the main scroll bars at the edges of the screen. The problem with that is that I it would mean couldn't lay out my front panel to match the system block-diagram as I have so far.
Does anyone know how to do this?
Solved!
Go to Solution.

I know I can show the scroll bars at the edge of the VI. In my case that's not very useful. The front panel shows a block diagram of a system. It's made up of a set of clusters which control various parts of the system. I want to keep this layout because it's very useful in explaining to people new to the system how it works. I inherited that approach from a previous iteration of the program for an older system. The problem I have is that the new system has far more control parameters for one of the blocks. Unfortunately it's one of the blocks in the middle of the block diagram. If it were one at the left, right, top or bottom it would be no problem because the main scrollbars could be used.
I can use a tab-control, that's my fall-back plan. The problem is that would be abusing the purpose of the tab control. In a tab control each tab is supposed to deal with a group of controls that have a common connection. So, all the things in tab #1 are supposed to be connected in some way and all the things in tab #2 are supposed to be connected in some way. There not supposed to be a way of gaining more screen space.
The controls I'm dealing with are numeric controls, switches and rings.

How do I get the Label for a Front Panel Control to appear in the Block Diagram but not on the Front Panel?

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.

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,
Davey

Ben 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?

How can we get an image of selected area of the front panel

i am plotting some graphs and want a group photo of all those in one shot is it possible????
n i want to get the graph coordinates on the mouse click.....
i.e when i click on the graph at any place the values corresponding to it must be retrieved. how do we do that,,...
i have tried with the labview help but didnt get any help
help please????????

Here's a start. This will get the front panel image and display it as a picture indicator.
You could use an event structure to capture the mouse clicks on the picture control to set the image area. Then using the mouse coordinates (referenced from the image coordinates), you can get the image subset "Get Image Subset.vi".
Message Edited by vt92 on 04-20-2010 08:30 AM
"There is a God shaped vacuum in the heart of every man which cannot be filled by any created thing, but only by God, the Creator, made known through Jesus." - Blaise Pascal

How can I arrange the front panel?

Hello,
I’m using LV 7.1 and created a VI with many controls and indicators. It writes and reads data to and from a bus system. For that I used the flat sequence structure and many case structures.
Now I would like to order the front panel, i.e. by using the tab control only the data read or only the user settings should be displayed.
But using the tab control slows the whole VI down, so that a data recording in real time is impossible.
Are there any other possibilities to bring the front panel into order if the number of controls and indicators is too high for the screen?
Thanks in advance,
UoS

Do you mean that the CPU usage goes up and the PC responds slowly. If so, this is interesting. This is most likely related to a grphical element causing the system to slow down. The tab control should theoretically take care of this, but about a year ago I ran into a similar situation where a tab caused problem here. In that case it looked like controls that were partially displayed caused the problem and when using the tab control the problem was there even when displaying another page. If this is so, you can try to determine the source by scrolling the screen in different directions. Once the problematic area is moved off the screen the VI should run faster. This way you can tell which area has the problem.
Try to take over the world!

Can I build a XY chart control to define a spline on the front panel

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