More shared variable help

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• Network shared Variable breaks rtexe

  I have a cRIO-9063 which I want to use for the control (PWM digital output for pumps signals) and measurement (temperature and voltage) of a system. In the ideal configuration the cRIO would be able to take measures and rebroadcast to a PC for monitoring and logging. The PC must be also able to change the digital output PWM on the cRIO lines. The cRIO should be able to continue to operate when the PC is not available. To do this, I use Scan interface for data acquisition and shared variables (single editor, no RT FIFO) hosted on the cRIO for network communication.

  I have developed the code for the target cRIO as well as my host PC meets my criteria. However, this code only works in development mode. When I try to build and deploy a rtexe on the cRIO, it does not work. I reinforced to the back and made a simple LED flashing user vi, ensure what I create and deploy properly. Slowly adding things to this flashing vi, I discovered it's shared network variables that break the vi once it is integrated into a rtexe.

  After flipping through other-related posts, I'll include the following:

  -There is no object on the remote VI front panel. Simply add a variable node shared is enough to break the vi (when it is deployed).

  -J' tried including my shared variable library in support of the construction directory, but what I saw there is not copied during construction or deployment. I manually copied the library to the /home/lvuser/natinst/bin/data / directory on the cRIO, then used an invoke node to deploy the cRIO variables when the software starts first. Even when you include a delay of 10 seconds after the invoke node, it did not work, just a mistake of 1043 at "the method or property is not supported in this version of LabVIEW."

  -NSV is referenced as absolute

  Some details of my configuration:

  LabVIEW 2015

  cRIO 15.0

  NOR-RIO 15.0

  Communication via ethernet, static IP

  Any help would be GREATLY appreciated. I suspect that I forget a few minor step or detail, otherwise am poorly understand exactly how and when shared network variables are deployed.

  I found shared to not be worthwhile over the years network variables.

  The RT EXE is not able to use the library to deploy to deploy the shared Variables.  See Help topic: http://zone.ni.com/reference/en-XX/help/371361M-01/lvprop/app_libdeploy_library/

  In general, SV are deployed once the project and they persist through reboots of the RT system.  In general, you should have a startup routine that checks the shared variables and expected for there to be without error on a node of the OAS and then move on to the rest of the program, defining the commissioning of values and check that they spread in the engine of the Variable is a typical method.

  See here for more information on the deployment of a variable in an application of the RT.  http://digital.NI.com/public.nsf/allkb/990508969805A7C086257619007189E7

  The section deployment of Variables shared in a real-time (RT) target running Headlessly is downstairs.  Because you are connected to an HMI PC, you should be able to use the library to deploy feature of the PC code targeting the cRIO.

  Usually, it's a faster, more scalable solution to replace your shared network Variables with a stream of network dedicated to the HMI and another for HMI - RT EXE commands.  You can send complex structures such as a cluster or even define the message as a cluster of enum and variant type to be able to use the Enum to convert the variant correctly according to the Enum value.

• Shared variable RT FIFO (multi element) - read both

  Hi all!

  I'm trying to collect data from analog inputs on my cRIO with a time step of 1 second. For this I use a timed loop and a variable shared with RT FIFO active (several table of doubles). Along with the timed loop, I also use a while loop that is significantly slower (lets say 10 sec period) who must read all the berries stored in the FIFO and write it in a .txt file (everything is run locally on target RT). Is it possible to empty the shared variable RT FIFO at the same time, and if not how can I get a number of tables that are currently stored in a shared variable?

  What is the difference between one created using the palette of FIFO of Real-Time/RT and RT FIFO created by a shared variable? I prefer to use the shared variable instead of Real-Time/RT FIFO allowing also time stamp.

  Best regards

  Marko.

  Marko,

  We recommend that the nondeterministic loop run faster than your deterministic loop and remove samples when they become available. If you don't want to do this, you can simply place your RT FIFO loop for the value to perform 10 iterations and then put that in your loop. For more information about the differences between the RT FIFO and Variables shared with RT FIFO active, please see pages 32 to 35 of the CompactRIO Developers Guide link below.

  http://www.NI.com/PDF/products/us/fullcriodevguide.PDF

  I hope this helps!

• Are published network shared variable write & read Atomic actions

  Hello

  I have a very basic question about shered (published network) variable.

  I think I know the answer already, but since I couldn't find in my documentation, I thought that it is more prudent to request...

  Are reading and writing on a shared variable of stocks Atomic?

  To be more precise: on my target real time I create an array with data (each element being the configuration item or a cluster containing name, value, and type) and when the table is finished I am this store in a published network shared variable.

  On my host (Windows), I'm voting (in a loop) until the table contains at least 1 item, when this is true I'm parsing all the elements in the table.

  Is there a chance that, reading of the shared variable, the table contains a subset of the original painting on RT target (i.e. the action of reading takes place while writing is still ongoing).

  Or is the action of reading delayed until the write is completed? (i.e. both write and read actions are atomic even over the network)

  I think the latter is true but not could find no evidence in the documentation.

  Kind regards

  SoC

  Hello Rob,

  Yes, you can access the entire value, data type - you use both. For the table data type, the integer value is actually the full picture. So, Yes, you can see reading and writing as Atomic actions.

  But, on the other hand, you can lose data if the RT system rewrites the variable before the host had the time to read. To avoid this, you can enable buffering for the variable. See the following links for more information:

  http://www.NI.com/white-paper/4679/en

  http://zone.NI.com/reference/en-XX/help/371361H-01/lvconcepts/buffering_data/

  Finally, you can also activate a FIFO RT on your target RT if you need to send data through the variable in a deterministic section of the RT. See also, more information:

  http://zone.NI.com/reference/en-XX/help/370622H-01/lvrtconcepts/rt_projectvariable/

• Delay weird read shared variables

  Hello

  I'm working on a project were I am followed a few lines of production. I use an OPC server on the DSC module to connect to PLCs on the production line and I created variables related to my labview tags of the PLC project.

  On my project, I have a main VI were I show information on production lines and I can access several subVIs were I see more information on these lines. Then I a VI that runs in the background were I read about 50 shared the PLC variables and where I save data in a MySQL database, data entry of data on the database of the Citadel and the recording of alarms.

  The problem I have is that I noticed a delay read variables that read weight of containers from the production line the VI that runs in the background. It seems that all shared variables suffer no delay, only the variables weight start to make some delay when the values are on the rise. It also seems that when I run only one VI, without running the main VI, there is no any kind of delay. I read shared variables shared as variable nodes.

  Can someone help me understand what is happening and how can I fix this delay? The VI that runs in the background is time critical and a strange delay like that messes up my data.

  Hi Mateus23,

  The shared variable has various capabilites buffering, including integration with real-time FIFO functionality in LabVIEW Real-time.

  I guess that buffering settings are causing the unexpected behavior.

  Check out these resources:

  Buffer Network-Published static Variables (white paper)

  Properties shared Variables dialog box

  - Network Page

  - Page FIFO in real-time

• VBAI: How to read a shared variable?

  I'm doing my inspection to do things that depend on the value of shared Variables. How to set the VBAI Shared variables, it is obvious, but I didn't understand how to read them and then create some kind of a structure of MATTER using this variable.

  Any ideas on how to implement such an architecture?

  I create two different States and use the transitions that are based on the value of the shared variable. You can read the value of the variables or the previous measures in stages that allow this (not all stages, but most don't) or transitions. To create a new State, go to the state diagram (click on the 'toggle window view hand' so the State-transition diagram is in the main part of the window). Right click in an empty part of the state diagram and select "create a new State".

  To create a transition, right-click on a State and select 'Create a new Transition' and drag the transition to the new State.

  To change the transition, double click it and you will be able to select the shared variable as measurement, and comparison operations to make the decision. If this comparison is false, the default transition is taken instead.

  Select help > Show context Help if you change the schema of the State for more details on how to use it.

  Hope this helps,

  Brad

• Properties of shared variables

  Hi all... I'm looking for a tutorial or article knowledge base explain the following:

  Use: Labview 8.6 Professional RT, none module DSC (impossible to spend right now, no funds available)

  System: PXI (called targets) communicate with various instruments and a PC (called host) by TCP/IP. operator enters variables of control through Labview program separate running on PC (XP).

  Background: development of the Labview project from version 4.3, made only another project of RT PXI, who communicated with an HMI via Modbus.

  Question about shared Variables: on my last project of RT, I had to 'read' all shared in the PXI program variables before you use them so that they would be 'available' to the HMI. I don't know that I'm creating variables properly now:

  Set up the 'network Variables' on the PXI system with the following properties - Type: network has published, the network: use buffering, the number of elements: 1, RT FIFO: enabled, the number of items: 1, FIFO type: single element

  Side host, I defined the same variables with the following properties: allow Aliasing and link to: URL of the PSP.

  It seems that I have to set the same properties as the other variables: network: use buffering, the number of items: 1, etc.

  What is the correct way to do this? I read a few posts on the problems of "deployment" variables, if the program PXI or the program host is and such. I saw one or two things 'flipped' passes, is not up to date variables. I just want if sure I do this correctly. PXI will always control if the host program does not work.

  Thanks for any help and I will continue to look for more information. And, just to remember, there is NO money available to upgrade my software now.

  
  

• cRIO and 9234 modules do not work or communicate via fpga with accelerometers, fpga, connected to the real-time application is also related to shared variables related to modbus slave

  Hello

  I have a compact rio, which has a 4 way frame this chassis is the three modules of ni9234, they are related using FPGAs for application in real time, then using shared variables in the low-speed loop associated with a slave modbus to communicate with the domain controllers, the nor 9234 accelerometers linked to them with option ac coupled iepe on c modules , my problem is the real-time application seems to work well even when power loss occurs it restarts without problem and the fpga written hard disk portable bin files very well, but without an accelerometer connected I get readings of low noise as soon as I connect an accelerometer to one of the outputs 10 it just goes to a fixed number (0.03125) as soon as you unplug it again He returned to readout noise, I ran a scan on the modules and get only a spike when I connect or disconnect the accelerometer, I tested voltage at the pins on the module and I get 22 volts CC which makes it more likely that the material is not the problem, but software is perhaps the cause to hang up, I join the project and files for your perusal. I also realized a new project which, in mode directly linked scan has the module entry in the shared variable and the scenerio even once again. Help would be appretiated.

  Thank you very much

  Jason

  Whren using waveform with the 9234 acquisition, we recommend the following FPGA and RT model.

  http://sine.NI.com/NIPs/CDs/view/p/lang/en/NID/209114

  It can be extended as a datalogger with:

  http://zone.NI.com/DevZone/CDA/EPD/p/ID/6388

  or using shared variables combined with the analytical engine

  http://zone.NI.com/DevZone/CDA/tut/p/ID/9851

  The FPGA in all this, as well as the framework of RT have used successfully by 1000s of users.  I recommend giving these a try.

• Shared variable between 2 LabVIEW executables via the network

  Hello, I need to create a number of network shared variables by two (built with LabVIEW 8.6) executables running on two different computers on a local network. The library to invoke node returns an error when you use a different IP than localhost. even more, it is not clear to me what exactly I have to do (what executable deploys the library, on which targets, activate the link or not, so on...). Thanks for any help, if you have already managed to make this communication works properly...

  Thanks for the replies. I've found the last two documents, but the first one is the most interesting: if I can't put the sources of two applications in a single project, I will move to another solution (data as suggested by Mike sockets or TCP). The two original projects are larger, and their merger would lead to such a huge thing!

• shared variable creates sound - problem, save data in crio

  Hi all

  I have a problem here...

  Why I get noise when using shared variables in my labview code...

  but when I remove these shared_varibles, the sounds are totally reduced...

  I use the shared variable for the data record. For the recording of data, I do a VI special folder under my computer. During my actual code CRIO.

  These two screws are to communicate using shared variables. Is there a better way to make the real-time recording apart from the use of shared data variables?

  I tried to record data directly to CRIO but it always fails... That's why I do a special VI under workstation for the logging of data...

  But if shared variables create sounds... my data record is no longer valid...

  Please help me...

  I downloaded some pictures... I hope that makes my problem clearly to you all...

  Hello auralius,

  Are these plots you have posted on the graph of velocity on the block diagram?

  I think that shared variables are affecting the timing of your loop and so affect the outcome.  I suggest you to add code to check if one of the iterations is late.  I suspect that the end iterations will correspond to the bad data that show you.

  You can try to enable the RT FIFO on the shared variable or you may need to add a second loop of communication and use a form any local communication to pass data to it.

  Take a look at http://zone.ni.com/reference/en-XX/help/370622G-01/TOC1.htm, including the sharing of data in deterministic Applications section for more information.

  Let me know how it goes,

  Sebastian

• to connect to a shared variable (android)

  Hello

  I just started to learn how to use the dashboard data Labview for android.

  I made a very simple project, with a VI that generates random numbers. I also added a variable published network shared in this project, and I write the random number generated for this variable shared every second.

  I would like to read this value on my phone (Motorola Razr i, Android 4.1.2) android using the dashboard of data for an Android application.

  I have a wireless access point and both my laptop (that hosts the project, LabView, Labview 2013) and my smart phone is properly connected to the wireless router, and both gets from dynamic IP addresses.

  I start running my VI on the laptop and the variable shared within the lvlib correctly deployed and began to broadcast (I guess) its value to the network.

  I start the DD application on my Smartphone, I choose 'Connect shared variable to', I type the local IP address of my laptop, which is 192.168.0.100, and I try to connect.

  After some 'research' and waiting, I get a message "connection error".

  Do I did wrong?

  Thank you much for the help.

  Best regards

  
  

• Update of address of the card "shared Variable.

  Hello Experts!

  I have a question about shared variables:

  Now I create a variable Shared (81O_G01) in the library, and it is related to:

  My Computer\SVCREATION.lvlib\Modbus1\410611

  Question is: How can I change this address SV (410611) when tha variable has already been opened?  is this possible?

  Thanks in advance!

  Anibal

  Hey Anibaldos,

  Looks like you're trying basically change the binding of a /A1 to /A2 variables at run time. I think that there are a few options for this:

  (1) in LabVIEW DSC, you can access a hosted variable and change the link address by using a property node. If you run the server modbus on a windows machine, this is the best option. Otherwise, I'm guessing you don't have a DSC. If this is the case you can always edit links by editing the library manually, but it seems that this will not help you.

  (2) it may be possible to open a variable connection shared using pallets (Data Communication > shared Variable) to this specific address, to which cases you have no need to use the shared variable. You can simply open a connection to two addresses different modbus and read one or the other as needed.

  (3) if #2 does not work, then I think you can still use datasocket API to perform such an operation. There is a bit of research you need to do to use it (for example, URL editing and UI thread problems), but it does not work. In my opinion, this is the approach taken by this document: https://decibel.ni.com/content/docs/DOC-13508 (I know from experience, you have to dig a little to find the screw, but they are there).

  (4) you can use the Ni Labs library: http://ni.com/labs

• There is no chance to install a standalone engine shared Variable of EVS?

  Hello!

  I wrote a small application that reads the values of a NetworkVariable created on the local computer. The address of this variable is something like \\127.0.0.1\System\test1

  That I can see, I can use this type of variable (I mean System -based) that if I installed an EVS (by Measurement Studio). But to install Measurement Studio, I need too Visual Studio...

  There is a way to work properly with NetworkVariables based on a system without having to install everything as I said before? AES is responsible for the correct operation of NetworkVariables? In this case, is there any chance to install a standalone engine shared Variable of EVS?

  Thank you!

  I found the solution to help NI MeasurementStudio 2008:

  Server deployment

  In this scenario, you must deploy the motor Variable shared to another machine that plays the role of the server. To deploy the shared Variable engine, you must run an installation on the target computer. The required Installer is installed with Measurement Studio for the [InstallDir] \ Redist\NINETVARSERV folder.

  You can view all the command-line options to run the installation program with setup.exe /? . Command line options, you can choose to run the installer in silent mode.

  You can use the Variable Manager to create and configure network on the server variables. The variable Manager is installed by default. To run the Setup program without installing the Variable Manager, run setup.exe /prop VARMANEXCLUDE=1 command. To run the installation program of engine Variable shared in silence and without the Variable Manager, run setup.exe /q /acceptlicenses yes /prop VARMANEXCLUDE=1 command.

• error in the terminal of a shared variable

  I read in the help of Labview entry 'Error In' to a shared variable provides a feature of "type error in. What I am unclear on the subject, is that if an error occurred before the shared variable, it will cause the shared variable NOT to do what it is supposed to do? If an error is passed to the entry 'Error In', the variable node still shared read/write as normally?

  Lol mistake-type functionality means that when an error is passed, the node will not run.

  (You can check yourself by writing a simple VI.)

• Pass a reference to the shared variable

  I use two shared variables in a loop where I write one and read each other.  I need to repeat this loop 5 times, but each loop uses a different pair of shared variables.  These variables are shared between a vi on the computer and a cRio.

  It would be ideal to incorporate this loop into a Subvi where I can pass a reference to the two shared variables in and then read and write in threw these references.  Then I could just call this Subvi 5 times, instead of copying and pasting the loop 5 times.

  Is it possible that I can accomplish this?  I can't find an example that would achieve this.

  Thank you

  If I understand correctly, you can use the mode programmatic access to shared Variables and it would work.

  http://zone.NI.com/reference/en-XX/help/371361H-01/lvconcepts/sv_usingdynvarapi/

  http://zone.NI.com/reference/en-XX/help/371361G-01/lvconcepts/usingdynvarapi/