Running Slope Display on Front Panel

I am slowly building a vi that records and displays pressure from a pressure gage. Right now, it continuously reads pressure, then every minute it will write the pressure, time, and date to a text file. It also plots to a chart once a minute. I can post the vi later, but I can't access it from this computer.
What I need to do, is program it to calculate a running slope from the data points. I need some sort of cache that will hold the most recent 15 pressure readings, and use them to calculate the slope and display it. When a new reading is taken, I need the oldest pressure to be kicked out and the newest one added to be used in the calculation. Any ideas on where to start with this?

I know this is an old thread, but my work took me away from this and has brought me back around. Never did get it figured out.
Tim, I did try it exactly as Jeff has it. Then I made modifications and it still didn't work. The slope desplay still shows NaN. Also, It only reads/logs pressure one time, then the rest it plots a 0 even though there is actually pressure on the system. I've attached the most current version I have that includes suggested changes.
Attachments:
PorosimeterPressureRS.vi ‏63 KB

Similar Messages

How to display remote front panels of subvis that are already open

I inherited an RT project that uses remote front panels for nearly all the user interfaces. The host application opens a remote front panel the the top level RT vi, and there are several subvis on the RT system that are opened from that top level vi and thus displayed on the host (i.e. their "Show Front Panel When Called" properties are set TRUE).
If the Host loses its connection to the RT system when any subvi front panels are opened, and the host application is restarted, it can re-open the top level vi remote front panel, but all the RT subvis that are already open will not display their front panels. I am looking for a way to open the front panels to these subvis from the host application.
The kicker is, I need to know which subvis are actually running before I attempt to open remote front panels. Is there any way to determine what subvis are actively running (and not just in memory, such as subvis that won't get executed until the top level vi reaches a certain state)? I am thinking that I could create a list of the subvis that I need access to, check to see if any are actively running on the RT system, and then invoke a remote front panel connection with those that are running.
Does anyone have any ideas as to how I might be able to do so? Or any other suggestions? [and yes, I know that RFP communication is probably not the best way to go, but we're too entrenched in this software to start over with a new system!]

TurboPhil wrote:
If the Host loses its connection to the RT system when any subvi front panels are opened, and the host application is restarted, it can re-open the top level vi remote front panel, but all the RT subvis that are already open will not display their front panels. I am looking for a way to open the front panels to these subvis from the host application.
It might be possible to work around this behavior by placing VI invoke nodes in your top level VI that reference each of your subvis and setting the Wait Until Done invoke method to false. This should cause the subvi to close when the top level VI closes even in the case of an unexpected restart.
You can access this invode node in the functions pallet by selecting Application Control » Invoke Node and also selecting Application Control » Static VI reference. Wire the Static VI Reference to the vi reference input node and double click the Static VI Reference and select the appropriate subvi in the dialog window. Left click on the Method section of the invoke node and select Run VI. Finally right click on the Wait Until Done invoke method and select Create Constant and ensure this constant is set to false.
TurboPhil wrote:
The kicker is, I need to know which subvis are actually running before I attempt to open remote front panels. Is there any way to determine what subvis are actively running (and not just in memory, such as subvis that won't get executed until the top level vi reaches a certain state)? I am thinking that I could create a list of the subvis that I need access to, check to see if any are actively running on the RT system, and then invoke a remote front panel connection with those that are running.
You can access this information by using the Real-Time System Manager (Tools » Real-Time Module » System Manager). This can be used to show what VIs and subvis are loaded into memory and which are running.
For more information on using this tool please referere to this Knowledge Base article.
Message Edited by BLAQmx on 02-18-2008 11:40 AM
Mark
LabVIEW R&D

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 to get Labview RT to Display a Front Panel on the Graphics port

I suspect that this post belongs on the feature request board but I'll ask anyway.
Most of my systems require a seperate PC for a SCADA/HMI/User interface linked to the RT controller using Network Published Shared Variables.
I understand that Remote Panels and Web Interfaces are also an option, bu still requires a PC to Access them.
I use high end RT controllers such as PXI, CRIO, and of 3 hours ago Desktop PC's.
Each has a DVI or VGA port connected to a graphics processor.
What I would like to be able to do is display my main VI front Panel to a connected monitor.
A possible solution is to use a windows OS but it is no good for a precision realtime system.
Any thoughts?
iTm - Senior Systems Engineer
uses: LABVIEW 2012 SP1 x86 on Windows 7 x64. cFP, cRIO, PXI-RT

Dan,
As above, Web interface still requires additional hardware of some sort.
Apple is a closed system so loads of prlems with 1/2 the market,
I am warming up to the hypervisor, I just don't like the idea of it taking out an entire core (on a dual core system). And needing a windows licence to go with it as well.
A quad Core PXI puts a gaping hole in my budget, makes a second PC not seem so expensive.
Would be great if I could get it on a Desktop, quad cores are pretty cheap now.
iTm - Senior Systems Engineer
uses: LABVIEW 2012 SP1 x86 on Windows 7 x64. cFP, cRIO, PXI-RT

Run Vi from the front panel...

I'm trying to run a vi, but not from a run botton, and not even by the execution properties. I'd like the vi to run when i turn on same logic botton on the front panel. Is it possible? Thaks, sorry for my bad inglish. Obrigado.

It is possbile to selectively run a vi using the VI server. I guess in your case you will still need to run a main to control the logic button. Check here for more information.

Cannot get HOSTNAME to display on front panel on my new WC5955's like I can on my old WC5755's

Hi, I have set the Display Device Information option under General Setup (used to be under Security) to "HOSTNAME". I get an error stating that the HostName is not fully qualified. For security reasons, we use static IP addresses and do not want our copiers registered in DNS. We use the queue name for our host name and device name. We require that print queue name to be displayed on the copier's front panel so the users can easily identify the print queue name of the copier. The last 3-digits of the queue name is the 4th number in each printer/copier's IP address. The old WC57xx Series copiers happily display their hostnames without restriction. Why was this changed? Annoying!!! -John

After years of battling over the security issues resident with Netbios over TCP/IP Xerox has it seems removed "Windows Networking" from all current devices. This is the same thing that disables the use of scanning to a hostname instead of an IP in a non-Domain environment. Your only option here is to lie and put it manually via choosing "Contact Name" and filling in the hostname:

Missing run stop button both front panel & diagram

Hello,
I have a VI a colleague gave me and one of it's subVI is missing all the buttons.
It is not the usual trick of custom window appearance, there are no buttons even in the diagram, and in properties, I'm not allowed to check the box to display them. (see snapshot attached)
As you can see, in Execute menu, I can't either run or stop (sorry the interface is in French) , but I can go to execution mode, or execute step by step, and the subVI runs normally.
Anyone ever seen such a weird thing ?
For info, I'm using Labview2012 and the VI is from Labview2010 and it's not protected.
Solved!
Go to Solution.
Attachments:
weird VI.JPG ‏82 KB

I am guessing that the priority (VI Properties -> Execution) has been set to subroutine.

Display on front panel of what state vi is in

I would like to find away to light an LED when the vi is in a state indicating on the fron panel what point it is in, any ideas.
Attachments:
timedBackbone.vi ‏77 KB

Well, a single LED alone will not show you what state it is in. It has only two states (On/Off), but your state machine has many.
You have a few possibilities:
Just create an indicator on the enum wire in the loop. It will give ou the state in clear text.
Create an indicator for any particular state, repeat if needed. (for example, the LED in the image wil light if state is in "exhaust four".
Create a 12 element boolean array each corresponding to one state and turn them on as a function of state (using replace array subset)
The image below show a few possibilities. (And please try to wire left to right for clarity).
Message Edited by altenbach on 07-13-2006 03:45 PM
LabVIEW Champion . Do more with less code and in less time .
Attachments:
States.png ‏7 KB

VI locks up when front panel is displayed

Hi
Firstly, I apologise if I’ve sent this to the wrong forum – I’m not sure if this is a TestStand or Labview related issue or possibly both.
I have a test procedure developed using Labview 7.1 and TestStand 3.1. It’s run from TestStand’s Operator Interface VI (full version), and executes about a dozen TestStand sequences in turn which call lower level VIs that perform the actual tests.
The code was written on a Dell GX240 Pentium 4 PC, with Windows 2000 + SP4 installed and runs without a hitch. However, I also have a second PC, same model & spec, but running Windows XP + SP3 instead of Win2K. I’ve also installed the same versions of Labview & TestStand on it, and copied across all my TestStand sequences & VIs into the same working directory. However, when I run the program on this machine, again using the same Operator Interface, it executes until about half way through and then hangs up.
In several tests, I call up a graphical user interface VI which displays a picture and prompts the operator to click on either a ‘Pass’ or ‘Fail’ button – the actual text being passed as a parameter. When the lock up occurs, the front panel is displayed, but there’s no picture and the buttons are blank. Up to that point, previous calls to the VI have executed ok.
If I modify the step that causes the problem, to call another VI - for example, a sub VI that doesn’t display a front panel - the new VI executes and the program continues to run. If I then change this VI’s configuration so that it’s front panel is displayed at run time, the problem re-occurs - the front panel outline appears but everything then freezes.
Attempting to close the front panel window, results in either error code –18001 and the message ‘an error occurred accessing the Labview ActiveX automation server’ being displayed or the Windows prompt to close Labview as it’s not responding. Usually, clicking ‘End Program’ causes the PC to crash out & re-boot.
Skipping TestStand sequences, whether they execute the GUI VI or not, just moves the point where the lock up occurs further down the list of tests, to the next step where the GUI VI is called. It’s almost as if something isn’t being closed properly when the program runs, and eventually reaches some limit, but why this doesn’t appear to effect the Windows 2000 PC, I’m at a loss.
Very much appreciate anyone’s thoughts.
Thanks
Bruce

Hi Bruce,
I found a KnowledgeBase article relating to the error you are seeing.
It describes error 18001 "Error occurred accessing LV activeX automation server".
Let me know if this helps you out.
This problem may also be due to how you have configured the Distributed COM (DCOM) settings on your machine. You will need to ensure that your DCOM settings allows the LabVIEW ActiveX Server to be launched and accessed through ActiveX automation. Even Administrator accounts can be denied launch and access permissions. To modify these permissions follow the steps below for Windows XP:
Login to Windows using a UserID that has administrator privileges.
Select Start»Run and enter dcomcnfg.exe. This displays the Component Services dialog window.
Navigate to Component Services»Computers»My Computer and select DCOM Config. Ignore the warnings that may appear.
Right-click on LabVIEW Application, TestStandLVRTS or the name of your LabVIEW ActiveX Server and select Properties to open the LabVIEW Application Properties dialog window. Select the Security tab.
You must give permission to the appropriate users so that they can access the LabVIEW server. You should give everyone access permissions and appropriate users launch permission. Only users who have launch permission will be able to access the server. Add permissions by selecting Customize and Edit for each of the three permission settings and manually adding permissions for each user.
I doubled checked that LabVIEW 7.1 and 3.1 are compatible with windows XP and they are. Just to make sure, it is 32bit or 64bit you are using?
Let me know how you get on.
Kind Regards
Lewis Gear CLD
Check out my LabVIEW UAV

Connecting extra monitor to DVI-I connection EVS 1464 (displaying Front Panel)

Hi,
Currently developing a Vision system using the following:
LabVIEW 2010 SP1
LabVIEW 2010 Real-Time SP1
Vision Development 2010 SP1
EVS 1464
My question is:
How can I display my front panel, running on the EVS, on a monitor connected to the DVI-I output of the EVS 1464?
Thanks ahead!
Roy
Solved!
Go to Solution.

Hi Roy, I'm not sure if Hossein actually read that KB or not, but it deals with displaying the front panel over the network on a Windows machine, not out through the monitor connection on the EVS running LabVIEW RT.
To answer your original question, no, it is not possible to view the standard LabVIEW front panel on the RT system today. All the code for displaying all the front panel UI buttons, controls, and indicators is simply not present in LabVIEW Real-Time and is only viewable on a seperate machine that is either running the development environment or using a web browser that has the LabVIEW plugin installed.
Having a UI display on RT is certainly a requested feature and perhaps it might be available some day. You might want to check this request: http://forums.ni.com/t5/LabVIEW-Real-Time-Idea-Exchange/Real-time-display/idi-p/1391108 . It has some good ideas for what other alternatives exist today as well.
However, this is one way to use the monitor output on the EVS and other LabVIEW RT systems. Vision Development Module includes RT Video Out VIs that can display any image on the connected monitor. You can either display images captured from cameras or custom images, as well as overlay text and simple graphic objects (lines, circles, rectangles, etc). It is certainly more effort than the normal front-panel editor in LabVIEW but it might be suitable for your needs if you want a few things to display. Of course you will have no mouse/keyboard so you cannot interact with any on-screen elements directly.
Eric

Show front panels of sub VIs when running a EXE (build application)

I've created a exe file and it works fine. However, it only shows the front panel of main VI and I can not open sub VIs (it looks like they are all hidden). I know it can be done by creating a library file along with this exe file, but that's not what I want. I want to create a single exe file that shows several front panels, and that can be run with run time engine. Is there any way to show front panels of sub VIs by running a exe file?

In the development mode, how are you displaying the front panels? Did you right click on the subVI and select SubVI Node Setup and choose 'Show Font Panel when called/Close afterwards if originallly closed' or did you choose the same options from VI Properties for each subVI. If the second, then the app builder will automatically retain the front panels of the subVI. If you chose the first option or if you are using VI Server to open a front panel, then the default setting in the app builder is to remove the front panels. You would then have to go the VI Setting tab in app builder and edit the settings.

Running log on front panel

I am thinking about creating a running log on the front panel of my VI. It is bascially a string indicator. Each time I write to it in my VI, the indicator will keep what is on there, and write on the next line. To do this, I am thinking about using a shift register to preserve what is in the indicator and continue to append to it.
Is that the best approach?
Yik
Kudos and Accepted as Solution are welcome!
Solved!
Go to Solution.

Ray.R wrote:
... since we are sharing ideas ...
I had implemented something similar to what SMercurio described, except that I used an ActionEngine. This allowed me to keep a log from any of the sub-vi's simply by "dropping in" the ActionEngine. It had additional features to enable / disable logging, select a file/folder, etc. Worked great.
Well, the core of it is an Action Engine. I just use wrapper VIs to perform certain functions. For example, there's a "Memory Log - Add Entry" VI that gets used by subVIs. That's just so I don't have to keep wiring the enum constant to specify what action to take. Gets tiresome after a while.

How to store character in file and display result on front panel

hi
currently i m working on FPGA project.i want to aquired data from FPGA board.i want to know about how to store character to file and contineous display each character on front panel in string format.
i have complete up to character display on front panel but only single character display when i want all character in string format.
Solved!
Go to Solution.

I don't see how this question is at all related to Digital I/O but it sounds like you just need a shift register with the concantanate string function.

Save sub-vi's (possibly closed) front panel image to a file

Hello,
I would like to dump a file of a sub-vi's front panel when that sub-vi completes execution. I was thinking of using the "Front Panel:Get Image Method", however the target sub vi's front panel might not be opened. I am looking through the help file, and it says
"If you do not want to display the front panel but want the image to reflect value changes, create a Property Node from any front panel terminal on the block diagram of the VI for which you want to create a front panel image."
I'm not quite sure I understand what that means. Can anyone provide an example?
I am running LV 8.2 for the record.
Thanks,
-Ted

Hi Ted,
"If you do not
want to display the front panel but want the image to reflect value
changes, create a Property Node from any front panel terminal on the
block diagram of the VI for which you want to create a front panel
image."
What that means is to create a property node for something (anything) in your Sub-VI.
I have attached an example for you with a dummy property node. And the front panel of the Sub-VI gets updated on the Main-VI. Try removing the property node in the Sub-VI and you will notice that even though the values are correct in the main-vi, the image of the sub-vi doesn't get updated.
Hope this helps!
Warm regards,
Karunya R
National Instruments
Applications Engineer
Attachments:
MainVI.vi ‏15 KB
SubVI.vi ‏10 KB

Is there a way the user can change the equation in the formular node from the front panel on the fly, dynamically?

Is there a way the user can change the equation in the formular node from the front panel on the fly, dynamically?

Sorry, I don't think so. That would be pretty cool if you could create a property node for a formula node and then enter a formula on the front panel and use it to update the formula. But you can't create a property node for a formula node and the only way of modifying the formula is by typing it into the formula node on the diagram. And you can't modify a diagram of a running VI.
You could create a VI which is only a formula node with the maximum number of inputs and outputs you expect. Have a button on the calling VI to Edit Formula. When the button is pressed, use a VI server to display the front panel on the formula VI, display a dialog box telling the user how to display the diagram of the formula VI, then stop the calling VI. (You can't edit a sub-VI while t
he calling VI is running). The user will then need to rerun the calling VI to use the new formula.
You might be able to do something by calling MatLab or something like that to get an interactive formula window.

Running Slope Display on Front Panel

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