Teststand: Running Multiple LabView vi's simultaneously

I am looking for a way to run multiple VIs simultaneously.. One will serve as an interface, one will log data to a database, and several others will interface with a number of hardware components.

Hi,
One way would be to run your VI's in seperate executions from a sequence file.
I've attached an example (TS 2.0.1f1 and labview 6.1 ).
The sequences are set so as the MainSequence will not complete until all three sequences are closed.
I have also added in the database.vi addition code encase the user pressed the terminate.
There are additional example on the NI website if you want to set the sequences to 'Do not wait'.
Hope this helps
Regards
Ray Farmer
Regards
Ray Farmer
Attachments:
MultipleVIExecutions.zip ‏40 KB

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How to acquire and display data from labview to excel simultaneously

hello,
I am using the NI-DAQ to measure the falling edges of a clock and display them into a table. What I need is to display these data in a table in excel while the program is running. In addition, when I receive a pulse from an external clock, for which I have created a digital channell, the data must be logged in a different column. In other words, every time I receive a pulse the data must be stored in the adjacent column in excel.

Hello Evangelos,
As far as I know and have experienced, it is not possible to access a spreadsheet file (or any file, for that matter) by two programs at the same time, you will get an error.
Also, a couple of observations on your code:
A constant wired to a case selector of a case structure makes no sense as the false case will never be executed.
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Can multiple executables run on Labview RT?

Can I execute processes on the Labview RT that are non-VI processes? From what I understand, the Labview RT is tightly coupled with the Pharlap RTOS. NI has tools to create an executable to run on Labview RT. Can I run other executables created from other applications? What if I want to run a Labview RT executable and a non-Labview RT executable on the Pharlap RTOS? The PXI-8196 RT controller will have a FAT file system? Can the PXI-8196 RT, with its Labview RT and Pharlap RTOS, initiate multiple executables?
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Hi Wayne,
Chris' answer was spot-on. To clarify the other points, the RT controller will require the FAT file system (FAT32 in the case of the 8196 RT), and you can only run one executable at a time. From within this executable, you can call DLLs and other VI's, but calling an external executable will not work. If you choose to create a DLL, I recommend using the DLL Checker 7.1.1 utility, which can be found in our KnowledeBase. This will verify that the DLL does not make calls to functions or libraries not supported on the Pharlap OS, since some windows libraries and function calls are not available in RT.
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Can multiple LabVIEW programs simultaneously access the same NI-DAQmx hardware?

I am developing a test station system that, in essence, runs several
seperate LabVIEW programs simultaneously on the same computer, each
controlling a different set of I/O channels on one shared set of NI
DAQ hardware (analog and digital I/O PCI boards with external signal
conditioning).
I have already gotten a system like this running almost flawlessly
using LabVIEW 6.1, NI-DAQmx 7.1 with traditional channels, and older
E-series DAQ hardware. So long as two programs do not try to write to
the same output channel simultaneously, everything works exactly as
expected--I can even read from the same (named) channel simultaneously
from more than one program. The only issue I have had is that if
one
of the compiled applications is closed (not just stopped, but closed)
while others are still running, Windows XP (SP1) will bluescreen on a
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I am now building a similar system using mostly the same software
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My question is this: It appears that I/O on M-series hardware must be
performed with new mx channels, with traditional channels not being an
option. I am therefore wondering if I will be able to do this kind of
multiple simultaneous access with mx channels, or if I must purchase
the classic hardware and use traditional channels for this somewhat
unorthodox application.
(Incidentally, the multiple simultaneous program thing is a
requirement for this system, as it is the only clean way to run
multiple
identical copies of the same complete program that only
operate on different I/O channels, and re-doing the program from
scratch is not an option.)

Dear Anonymous,
Thank you for contacting National Instruments.
To address your question, I don't know if multiple simultaneous access with mx channels is possible, but I do not see why it wouldn't be. The best way to find out would be to test it. I don't have your program or hardware, so I'm pointing you to some Compatibility VIs. These are VIs that look exactly like Traditional DAQ VIs except that underneath they call the DAQmx driver instead of the Traditional DAQ driver. If your device works when you substitute these Compatibility VIs in for the Traditional DAQ VIs, then you'll know the M Series boards will work for you.
Here is the link for information about the Compatibility VIs:
http://digital.ni.com/softlib.nsf/954feaeea92d90918625674b00658b
83/9d67f671bcc6850586256e630059308b?OpenDocument
Let me know if you have any further questions or if this does not resolve your issue.
Thanks again and have a great day!
Chad AE
Applications Engineer - National Instruments

Running a labview installer without installing drivers

Ouch. I have to install multiple LabView programs onto the same machine and they were all compiled with different versions. I don't have the luxury of rebuilding them. When I try installing some of them, the program won't let me install because newer drivers are already installed on the machine. Is there a way of running an installer to install the program without installing the drivers?
Solved!
Go to Solution.

The folder where the installer was placed into should have a bunch of folder in the "bin" folder all starting with "p". These contain the various installers that are run. The actual installer for your executable should be in there somewhere, so you could try running it directly.

Running multiple instances of a top level vi

The following question is copied from a 1999 post which I am also interested in an answer to. It wasn't answered in '99, but maybe there are more people around today who could comment;
"I am interested in running multiple copies of a top-level vi in Labview
operating under Windows95/98/NT much like you could run several copies of
notepad.exe simultaneously. Whenever I attempt to start a second copy of a
vi (or .exe), in either the development or runtime environment, Labview just
brings the first copy to the foreground. Is it possible to alter this
behavior?"

I think it is not a bug but an "open feature". What to do if there is 2 or more calls to the same VIT on the diagram? Should a new instance be created for each node or the same instance reused? It depends of the programmer's intents... The problem has been swept under the carpet allowing only one subVIT instanciation per diagram.
Back to the topic, one would have to be very careful to code an application where the same hierarchy of VIs has to run in multiple copies in parallel. User interface VIs has to be instanciated dynamically user VITs. What to do with subVIs with unitialized shift registers that shouldn't share their data amongst different hierachies? It is doable but requires a careful design. However for simple user display and
input, a VIT does the job.
The easiest way is to duplicate and run an executable file copy. That is because when a second instance of a LabVIEW executable is run, it detects the already running instance, passes the control to it and quit. With a different file copy of the executable, the application can be relaunched with its own application space where you can run the same hierarchy of VIs without conflicts.
LabVIEW, C'est LabVIEW

Use daq across multiple Labview applications

Is it possible to have daq handoff data to multiple Labview applications running at the same time? Each application is specific to a certain test setup, but each test setup has its channels run into a couple of scxi cards in one computer/daq card. One application may access channels 0,1,9,10 on scxi module 1 and channels 1,2,3 on scxi module 2; another application accesses channels 2-7 on scxi module 1 and channels 4,5,6 on scxi module 2; etc. (get the picture?). I want to turn each of these little applications into executables. Is it possible to have multiple sessions of daq running at the same time for the same card? Is this the idea behid tasks with daqmx? If not, can I create a small daq application that runs independently of my actual test apps, and somehow have one executable talk to another executable?

True enough, but I think it could work if you program it correctly. I am mainly thinking, have the daq application configure the channels no matter which application wants them. Have it also set the scan rate and other details based on the most critical channel. Have the daq application continously reading channels into a 2-d array, and buffer the data into a shift register. Then when one of the other applications wants data, it dumps whichever channels that app is asking for. None of the actual test application would ever request 'daq', but they would request data that has been stored from daq. I guess one thing I want to know is can I request data (such as a 2D array of dbls) across totally seperate executables?
It almost sounds like the perfect job for the new 'shared' variable type in Labview 8, but I am not familiar enough with its ins-&-outs.

Running multiple VIs?

Hi all!
I am still quite new to LabVIEW and I want to achieve listed below.
I have 3 different VIs:
1) VI 1 and 2 need starts simultaneously
2) Both VI 2 and 2 each contains a while loop internally
3) VI 3 is required to start after a time delay after starting of VI 1 and 2
4) All 3 VIs are stop after VI 3 complete its execution
Is it correct if I just simply put VI and VI 2 on the main VI for them to start together?
What can I do for 3) and 4)?
Attachments:
Pic.jpg ‏16 KB

JKSH wrote:
apok wrote:
Since you are new to LV, this can be intimidating....namely using notifiers,parallel loops and dynamic events.
Hi apok,
Why did you use user events instead of native events?
The OP has blocking subVIs that contain long-running loops; how does that intergrate with your architecture?
BTW, you can extend the Merge Errors VI to take 4 inputs (drag the bottom edge) -- no need to create an array first
answers:
producer/consumer architecture is highly effective in running multiple parellel loops or sub vi's with communications in between.
doesnt matter how long the sub.vi is running(that is still controlled by the producer loop), again producer/consumer architechture can communicate back whether with dynamic events(noticing that my example shows how vi3 can control the main vi by dynamic communication) or forth with data or UI control of the sub vi's by the producer loop through equeues or notifiers.
BTW, what you are probably seeing with merge error is an anomoly from translating between versions of LV, try it and see what i mean....believe me that i am not creating an array, its a bug. also, your use of flat sequences makes me question....
When Should I Use a Flat Sequence Structure?
Forcing execution with a flat sequence structure is useful for benchmarking code performance

What am I doing wrong when running multiple applications with the Web Server enabled ?

I am running multiple Vi's (applications) on the same Nt Workstation and the Web Server is enable for all applications. However, I am able to view only one Panel from the browser. Only the first application that is started can be viewed. What am I doing wrong ?

Only one application can act as a web server at the default http port 80.
To solve this either run all VIs into a single application or use different
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In the browser, you enter the URL for non default ports as
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HTH
Jean-Pierre Drolet
"zemaitis" a ecrit dans le message news:
[email protected]..
> I am running multiple Vi's (applications) on the same Nt Workstation
> and the Web Server is enable for all applications. However, I am able
> to view only one Panel from the browser. Only the first application
> that is started can be viewed. What am I doing
wrong ?
LabVIEW, C'est LabVIEW

Opening TestStand Ref from LabView sometimes fails

I'm having an intermitten problem when opening a TestStand reference from LabView. The error explaination just says, "LabVIEW: (Hex 0x80004005) Unspecified error." Attached is a little vi that can reproduce the problem when set to run continuously.
Any idea on how to fix this? Thanks a lot.
Note that because of compatibility requirements I have to use TestStand 2.0 with LabView 7.1.
Attachments:
TS_Ex.vi ‏24 KB

Attached is a screen shot of the error message. This is one of at least 2 error messages. I will get the other one when I can get time on the equipment. Right now, I would like to get the error log (mentioned in the screen shot), but I can't find it. Where should it be?
Unfortunately, the equipment is being shared and I haven't received time to debug it more. But this is what I have seen.
Trying to Highlight Execution with breakpoints seemed to point the vi closing the reference to TestStand as the source of the error message. Using the Simplified TestStand Operator Interface vi that came with TestStand, and some fake tests, we did not have this error. Only when we use our customized OI with dynamic test sequence generation do we get the error. This error doesn't occur with LabView 6.1. So I think it may be another incompatibility between LV 7.1 and TS 2.0.
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Attachments:
Exit-Crash-1.doc ‏24 KB

How to force TestStand to ignore LabVIEW errors

Hi,
usually where there is an error in the LabVIEW code module TestStand stops and gives a pouup message .
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Thanks

You can also work more globally - go to the Configure menu item and select Station Options.
At the bottom of the execution tab, there's a section for what to do on Run-time errors. -> Show dialog, Cleanup, Ignore or Abort.
Whilst not specific to steps configured to use the LabVIEW adapter (assuming you're mixing some programming languages) that at least get you continuing on to the next step without the dialog.
If you need to assess if it's specifically LabVIEW modules causing the error, then you need to use the Station, Process Model or Sequence File callback for On run-time error, and the step gets passed as a parameter. That would allow you to work out if the step was LabVIEW specifically and then make a decision as to what to do next.
Hope that helps.

CRIO Run Multiple Applications?

Is it possible to run muliple applications on a cRIO target? Would they all need to be part of the same LabVIEW project? Can I set more than one as a start-up VI or need to create a VI that would start up the individule applications? They are Ethernet bases and don't use or share any I/O. I looked around but don't see much information on this topic. Thanks!
Matt Fitzsimons
NI Alliance Member
NI Certified LabVIEW Architect
LabVIEW, LV-RT, Vision, DAQ, Motion, and FPGA
Solved!
Go to Solution.

Good Afternoon Matt,
It is possible to run multiple applications on a cRIO target as long as they're in the same project and don't exceed the memory capacity of the target. You can only mark one VI as the start-up VI but, as you mentioned, you could have this VI call your other applications. You may find the following documentation helpful:
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http://digital.ni.com/public.nsf/allkb/A7DBA869C000B5AE862570B2007C4170
Using VI Server to Run LabVIEW Real-Time VI's Stored on an RT Series Hard Drive
http://zone.ni.com/devzone/cda/epd/p/id/4364
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Can anyone point me to any documentation/examples out there for the TestStand Full-Featured Labview OI? I have tried looking just about everywhere and can't seem to find any good documentation/explainers on how the OI works and how to customize it. I am new to TestStand OIs and am trying to create an OI that allows me to run up to 6 different UUTs independently at the same time. I can't figure out how to wire in each individual Execution Entry point and am looking for examples and/or documentation. I also need some help with Progress bars and test status indicator LEDs.

Below is an example front panel of what I am trying to accomplish. Most of the controls are not connected of course :-). I am trying to have one window with 6 different executions shown within it. Each execution would be seperate from one another and you would be able to view each just by clicking on the tab for that particular test fixture. The only thing that would be common is that each execution would be running the same sequence file. The individual test fixtures could be at different points in the test sequence and could have different start and stop times for each. For instance....test fixture #1 could be loaded with a UUT and started into test then while it is running test fixture #5 could be loaded with a UUT and started into test. In the meantime when test fixture #1 has finished testing I could load another UUT into test fixture #1 while test fixture #5 is still running. etc etc
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I even tried running normal Firefox and Firefox Extended Support Release simultaneously, but I ran into the same error.

Disregard the question. The solution has nothing to do with any "Firefox bug". Turns out that my session wasn't being managed properly. Or rather, I was accidentally deleting other users' information when new users logged in. So if I had user 1 and user 2, and user 2 logged in after user 1, some of user 1's information would be deleted, resulting in the errors.
Oops; sorry about the false alarm. :)
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Running multiple files

Hello
I am trying to run multiple files with my java app on a Unix server. I compiled with javac, and run it thus:
java SNL *.mef
meaning I want to run all of the files with .mef suffix. Unfortunately it does nothing. If I just run one file at time this way:
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JM

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Teststand: Running Multiple LabView vi's simultaneo​usly

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