Shared Variable based on Array of cluster

Hello,
I've created a shared variable which is based on an array of cluster (typedef). The cluster only contians two double elements for x-y coordinates of a point.
Everything seems working until I found the shared variable can only hold the first two elements when I pass an array to it.
Are there any settings I've missed?
Thanks
Yan

Data is simply created and directly sent to SV.
The difference during defining the SV is:
Normally, when define an array SV, it allows to change the "Number of elements" (default as "2").
However, when define a typedef array SV, the option is gone. Does it then use the default number "2" as the number of elements?

Similar Messages

Strange behaviour with Vision 8.2 and Shared Variable 1D Image Array

I've just upgraded to LabVIEW 8.2 and Vision 8.2. When loading a particular VI, it is searching numerous times for ...\LabVIEW 8.2\resource\objmgr\IMAQ Image.ctl - which of course doesn't exist. As best as I can track it down, this seems to be cause by a Shared Variable I have in the project which is a custom control of a 1D array of Image.
So I've created a new project from scratch to illustrate (attached). The VI runs OK, but any editing means that this non-existant control is searched for again. Of interest is also that there is a coercion dot where the Image is used, but the data type on the wire seems OK. Creating a control (rather than a Shared Variable) works fine.
Anyone know what's going on here?
Message Edited by GregS on 02-26-2007 03:43 PM
Attachments:
1DImage.png ‏4 KB
1DImageShared.zip ‏15 KB

Hello Greg,
I downloaded your project and opened it up on my
system. I received the same results as you
did – I tried to open the project it searched for \LabVIEW 8.2\resource\objmgr\IMAQ Image.ctl. I also used the 1d Image.ctl file as a constant on my block diagram and it did not
show the coercion dot as you mentioned.
There does seem to be some strange behavior going on here
with the coercion dot and the shared variable.
I will have to look further into it and report this to R&D.
But for now, we need to address your application. What is the goal of your application? How does using a shared variable with IMAQ
Images help you get there? You may be
aware of this already, but when an Image wire is passed around LabVIEW, it is
not actually passing a copy of the data in a dataflow manner. The large size of IMAQ Images necessitates
that LabVIEW pass around a pointer to the IMAQ Image. Therefore, when an array of Image controls is
made and used as a shared variable, the controls do not contain the actual
image data. Instead, they contain
pointers to the IMAQ Images. When they
are passed into a shared variable, unexpected results may occur. If the shared variable is network published,
for example, another computer on the network would receive a pointer to an
image that it would not be able to find or access.
There may be a much better way than shared variables to
achieve the same functionality you are currently looking for. If you do in fact require shared variables,
you could use IMAQ ImageToArray.vi
to create an array that can be used in the shared variable like any other data
type, and then use IMAQ ArrayToImage.vi
on the other end to be able to view the array as an image.
Please post back with more information about your
application and we should be able to find the best solution for you.
Regards,
Luke H

Data Logging a programmatically created shared variable of cluster or array datatype into citadel DB

Hi,
Is there a way to log a programmatically created shared variable of cluster or array datatype into citadel DB?
I have attempted to programmatically create a shared variable of type 'double' and was able to successfully log the same into Citadel DB. In the attachment, Please refer to the attached project SV_TC.lvproj and specifically to SV_W.vi for the code that i have used (W.png file shows the dB in MAX and shared variable in NI Distributed System Manager)
However when i tried the same approach to create a shared variable 'array of double', i noticed that traces are not getting created and hence data logging isn't happening into the Citadel DB. I was however able to write and read the shared variable array without issues. The same is true with cluster datatype also. Please refer to SN_NW.vi for the code that i have used - only difference from SV_W.vi is that i have tried to create a shared variable of type 'array of double'
One observation is that if i create an 'array of double' or cluster in a shared variable library using the project explorer and deploy, i could see that these being logged into Citadel DB.
Hence i want to understand what could be done to achieve the same programmatically? Could you please advice?
Regards,
Sridhar
Attachments:
SV_TC.zip ‏3925 KB

Why is the transaction happening over remote?
Because we need the information to be on our database immediately when they submit it.
I don't know anything about streams or replication.....
The web database is run by the company that hosts our web site. We use PL/SQL to show the pages and output the html. It fetches the data the customer is requesting from our database, but I'm struggling to get the best way to insert into our database from there.

Debug shared variable array

I am passing data between a PXI RT Target to a PC Host using Shared Variables. Everything passes correctly between the Host and the Target, but Shared Variables that are arrays do not pass between the Target and the Host. Single elements whether boolean, numeric, or string pass from Target to Host with no problem. I use NI Distribution Manager to examine Shared Variables. How can you find the content of a Shared Variable that is an array, without writing my own VI?

This tool doesn't give me any more information than the Dist Sys Mgr. The SVs that are working show quality "good" vs "no know value" for the SVs that are not working.
My network-published SVs are single-writer 1D arrays (U32/SGL) of varying sizes (64-1005).
When I write to the SV I get error -2147024891 with the source being \\My Computer\Lib\mySV\\xxx.xxx.xxx.xxx\Lib\mySV where xxx.xxx.xxx.xxx. is the IP address of My Computer.
When I read the SV I get warning -1950679044with the source being \\My Computer\Lib\mySV\\xxx.xxx.xxx.xxx\Lib\mySV where xxx.xxx.xxx.xxx. is the IP address of My Computer. I get this warning when I'm reading the SV either from the target or the host.
I've checked the properties pages for the SVs and I don't see how LabVIEW is interpreting the network path twice. What could be causing this?
Also, if I delete a SV from my library of SVs it still shows up in the Dist Sys Mgr until I restart LabVIEW. Why?

How do you synchronize accesses to a LabVIEW Shared Variable?

I would like to create an ad-hoc weather station program (I'll explain more in a bit). I am using LabVIEW 8.0 Full Edition, and I would like to share data over a network between stations with the LabVIEW Shared Variable. Here's what I want to be able to do:
A node would start up, and begin publishing data to a network via a shared variable.
The shared variable is an array of clusters
The cluster information would hold things like:
Station Name
Station Location
Weather information cluster (temperature, rainfall, windspeed, wind direction, etc...)
Timestamp of last update
When a new node would like to enter, it would bind to the shared variable, grow the array, and add its information.
If a node's Station Name and Station Location is already in the shared variable, it would merely update the information in the cluster.
Viewing nodes could pop in, bind to the shared variable, and read/display the information at any time.
I am trying to enumerate problems with this before implementing, and I have run into a stinker of a problem that I am not sure how to solve. How do I synchronize accesses to the LabVIEW Shared Variable? If I read the variable, modify it, and write it back, I will undoubtedly run into a race condition where 2 nodes attempt to update its data and I will lose the data written by the first node - Node A reads, Node A modifies, Node B reads, Node A writes, Node B Modifies, Node B Writes, and thus the modifications made by Node A are lost. In my specific application losing some data isn't critical, but if not remedied this type of problem could cause massive amounts of data to be lost when there are numerous nodes, and that is definitely not acceptable.
Does anyone have any recommendations on how to synchronize the read-modify-write operations on the data in the Shared Variable?
-Danny

Wendy,
I am afraid Semaphores are not network-shared objects (to my knowledge), they are system-level objects that use operating-system synchronization mechanisms. If I were synchronizing on a single machine, a semaphore might be a valid mechanism; as an aside, most user-mode semaphores are designed to synchronize within a single process - to synchronize between processes you need to store the semaphore in the Kernel, and to synchronize over a network you would need a network node to handle serialization of requests. My Shared Variable is published over a network, and to my knowledge there are no network-published synchronization mechanisms available - mostly because there is no way to currently perform an atomic test-and-set on the Shared Variable (am I correct?) and there isn't a mechanism for blocking access to a Shared Variable from another network device/machine (or is there?). I've been looking for some way to implement an atomic test-and-set but I am running into a wall; I know that if I select the "single writer" attribute of the Shared Variable I can get LabVIEW to force a single writer allowing me to have an atomic "set", but I need more than that.
If only there was a network-shared Semaphore or some way to block other network accesses to the Shared Variable I would be in business - something like what I want doesn't exist, does it?
Thanks!
-Danny
Message Edited by texasdiaz on 02-23-2006 02:52 AM

Empty Shared Variables & Data Binding not working in dynamically called VI

Hi,
I have just upgraded a system from LabVIEW 2011 to 2012 DS2. I have a real-time PXI system running several shared variables, hosted on the PXI.
After what appeared to be a succesful upgrade I have a couple of odd issues.
1. The PXI writes test data into a network shared variable, based on a typedef of an array of custom clusters. The variable is disconnected from the typedef, as RT does not function with shared variables linked to typedefs. It seems that writing a seingle entry to the array is fine, but writing multiple entries causes the variable to appear empty.
I still need to debug this a little more, as while I was station to do so this other issue popped up.
2. I have some controls on the Host app with data binding to shared variables. The host app uses three VIs dynamically called into the wrapper VI. One of these called VIs is not able to connect to its variable when inserted in to the wrapper, but it can if run independently. The other two have no such trouble. Where I see a problem, the indication LED is grey and the mouse-over text reads "no status". What does this mean?
Any clues?
Thanks,
Ian

I have changed the Invoke Node to a Run Asynchronous node, and this seems to have fixed the data binding issue.
The other issue may be related to a bug fixed in 2012 SP1:
368648 Network Stream operations return Error 42 when data type contains nested clusters of typedefs
I am now getting error 42 when reading a particular network shared variable. This variable contains the results of measurements, in a data type which contains an array of nested clusters of typedefs. When there is a single entry in the array I can read the variable fine, but when there is more than one entry in the array it does not read and I get error 42.
I have downloaded 2012 SP1, and will see if this helps.
Ian

Shared Variables for Real-TIme Robot Control

I'm really stuck in my efforts to use LV real-time in my hardware control application. I have a 6-axis industrial robot arm that I must control programmatically from my PC. To do this I've developed a dynamic link library of functions for various robot control commands that I can call using Code Interface Nodes in LV (using 8.5). This has worked great, that is, until I tried to port parts of the application to a real-time controller. As it turns out, because the robot control dll is linked with and relies so heavily upon several Windows libraries, it is not compatible with use on a RT target, as verified by the the "DLL Checker" application I downloaded from the NI site. When the robot is not actually executing movements, I am constantly reading/writing analog and digital I/O from various sensors, etc.....
This seemed to suggest that I should simply segregate my robot commands from the I/O activities, using my host PC for the former, and my deterministic RT loop on the target machine for the latter. I set up a Robot Controller Server (RCS) vi running on my host PC that is continuously looking for (in a timed loop) a flag (a boolean) to initiate a robot movement command. Because several parameters are used to specify the robot movement, I created a custom control cluster (which includes the boolean variable) that I then used to make a Network Shared Variable that can be updated by either the RT target or the host PC running the RCS. I chose NOT to use buffering, and FIFO is not available with shared variables based on custom controls.
Here's sequence of events I'd like to accomplish:
1) on my host PC I deploy the RCS, which continuously pools a boolean variable in the control cluster that would indicate the robot should move. The shared variable cluster is initialized in the RBS and the timed loop begins.
2) I deploy the RT vi, which should set the boolean flag in the control cluster, then update the shared variable cluster.
3) an instance of the control cluster node in the RCS should update, thereby initiating a sequence of events in a case structure. (this happens on some occassions, but very few)
4) robot movement commands are executed, after which the boolean in the control cluster is set back to its original value.
5) the RT vi (which is polling in a loop) should see this latest change in the boolean as a loop stop condition and continue with the RT vi execution.
With the robot controller running in a timed loop, it occassionally "sees" and responds to a change of value in members of the shared variable cluster, but most times it does not. Furthermore, when the robot controller vi tries to trigger that the movement has completed by changing a boolean in the control cluster, the RT vi never sees it and does not respond.
1) Bad or inappropriate use of network shared variables?
2) a racing issue?
3) slow network?
4) should I buffer the control cluster?
5) a limitation of a custom control?
6) too many readers/writers?
7) should I change some control cluster nodes to relative, rather than absolute?
8) why can't I "compile" my RT vi into an executable?
Any help would be greatly appreciated. Unfortunately, I'm writing this from home and cannot attach vi files or pictures, but would be happy to do so at work tomorrow. I'm counting on the collective genius in the universe of LV users and veterans to save my bacon.....
David

Hi David,
I'm curious why you decided to build a CIN instead of developing the code in
LabVIEW. Is there some functionality that that LabVIEW couldn't
provide? Can you provide some more information about the LabVIEW
Real-Time target you're using? What type of IO are you using?
It is impossible to get LabVIEW Real-Time performance on a desktop PC running
an OS other than LabVIEW Real-Time. Even running a timed loop in LabVIEW
for Windows won't guarantee a jitter free application. Also, no TCP based
network communication can be deterministic. This means Network Shared
Variables are also not deterministic (they use a TCP for data transport) and I
advise against using them as a means to send time critical control data between
a Windows host and a LabVIEW Real-Time application.
In general, I would architect most LabVIEW-based control applications as
follows:
- Write all control logic and IO operations in LabVIEW Real-Time. The
LabVIEW Real-Time application would accept set points and/or commands from the
'host' (desktop PC). The Real-Time controller should be capable of
running independently or automatically shutting down safely if communication to
the PC is lost.
- Write a front-end user interface in LabVIEW that runs on the desktop
PC. Use Shared Variables with the RT-FIFO option enabled to send new set
points and/or commands to the LabVIEW Real-Time target.
Shared variable buffering and RT-FIFOs can be a little confusing. Granted
not all control applications are the same, but I generally recommend against
using buffering in control applications and in LabVIEW Real-Time applications
recommend using the RT-FIFO option. Here's why: Imagine you have a
Real-Time application with two timed loops. Time-loop 'A' calculates the
time critical control parameters that get written to hardware output in
timed-loop 'B'. Loop 'A' writes the outputs to a RT-FIFO enabled variable
with a RT-FIFO length of 50. Loop 'B' reads the outputs from the shared
variable, but for some reason, if loop 'B' gets behind then the shared variable
RT-FIFO will now contain several extra elements. Unless loop 'b' runs
extra fast to empty the RT-FIFO, loop 'B' will now start outputting values that
it should have output on previous cycles. The actual desired behavior is
that loop 'B' should output the most recent control settings, which means you
should turn off buffering and set the RT-FIFO length to 1.
There is also a clear distinction between buffering and the RT-FIFO
option. The RT-FIFO option is used to add a non-blocking layer between
network communication and time-critical code in LabVIEW Real-Time
applications. It also provides a safe mechanism to share data between two
loops running in a Real-Time application without introducing unnecessary
jitter. Network buffering is a feature that allows a client to receive
data change updates from the server even if the client is reading the variable
slower than the server is writing to it. In the example I presented above
you don't need to enable networking because the shared variable is used
entirely within the Real-Time application. However, it would be
appropriate to send control set points from a Windows PC to the Real-Time
application using network published shared variables with the RT-FIFO option
enabled. If it is critical that the Real-Time application executed all
commands in the sequence they were sent then you could enable an appropriate
buffer. If the control application only needs the latest set point
setting from the Windows host then you can safely disable network buffering
(but you should still enable the RT-FIFO option with a length of 1 element.)
Network buffering is especially good if the writer is 'bursty' and the reading
rate is relatively constant. In the robot application I can imagine buffering
would be useful if you wanted to send a sequence of timed movements to the
Real-Time controller using a cluster of timestamp and set point. In this
case, you may write the sequence values to the variable very quickly, but the
Real-Time controller would read the set points out as it proceeded through the movements.
The following document presents a good overview of shared variable
options: http://zone.ni.com/devzone/cda/tut/p/id/4679
-Nick
LabVIEW R&D
~~

Shared Variable communication (network publiched )

Hi all ,
The whole day I have been banging my head with Shared variable communication between RT Host and host computer :
I essentially attempted to pass an array from the RT host to the Host computer .For this purpose I used a Network published shared variable of type Array U64 . I utilized this link to help me understand usign shared variable communication
http://www.ni.com/white-paper/4679/en ..
I also enabled RT FIFO .Now in the mentioned link this the information given about using single element FIFO or Multi element FIFO
'' By enabling the real-time FIFO, you can select between two slightly different types of FIFO-enabled variables: the single-element and the multielement buffer. One distinction between these two types of buffers is that the single-element FIFO does not report warnings on overflow or underflow conditions. A second distinction is the value that LabVIEW returns when multiple readers read an empty buffer. Multiple readers of the single-element FIFO receive the same value, and the single-element FIFO returns the same value until a writer writes to that variable again. Multiple readers of an empty multielement FIFO each get the last value that they read from the buffer or the default value for the data type of the variable if they have not read from the variable before.''
I had read the above content a 100 times but still I am not able to get a clear picture of the difference and when to use which option .So I decided to throw away the text and attempted to try somethign out for myself .
I had a loop in the RT host that writes different 3 element arrays into the ''network published shared variable '' . Now when I use the multi element option with '' number of arrays as - 2 '' I am able to read the arrays seperates one by one in the host computer ( as we can read a general queue).
Now when I used the single element option for the RT FIFO with un editable 1 array option ,only the last written array into the ''network published shared variable '' gets read in the host computer .
This sounds absolutely silly as if this is the case then what is the purpose of setting the ''buffer''.For testing purposes I had set the buffer as 5 arrays .
In fact I have only one writer ( writing in loop in the RT Host ) and one reader ( again reading in loop in the Host computer ).So I am not even sure if I require The RT FIFO option for the network published shared variable .
I apologise for the long message but I have reached the limits of running in circles waiting to bang somewhere
I know I am doing a silly mistake somewher or I am probably missing a simple obvious trick but dont know what it is ..
I request for some clarity .. In fact I had posted a little while earlier today as well .... link - http://forums.ni.com/t5/LabVIEW/RT-Host-to-Host-computer-communication/td-p/2348130 )
any help would be appreciated
Cheers
me
Solved!
Go to Solution.

Hi,
I think the difference between both types is clearer in the LabVIEW help :
Enabling the Real-Time FIFO
You can enable the real-time FIFO of a shared variable from the Real-Time FIFO page of the Shared Variable Properties dialog box. Place a checkmark in the Enable Real-Time FIFO checkbox to deterministically share data using single element or multi-element FIFOs.
Single Element FIFO
A single-element FIFO shares the most recent data value. The shared variable overwrites the data value when it receives a new data value. Use this option when you need only the most recent value. Configure the size of the array elements or the size of the waveform for the FIFO buffer if you select an array or waveform data type.
Multi-Element FIFO
A multi-element FIFO buffers the values shared by the shared variable. You can configure the size and the elements of the FIFO buffer to match the settings from the Use Buffering section of the Variable page, or you can configure a custom size for the FIFO and the FIFO elements.
Note For both single-element and multi-element FIFOs, if the variable contains array or waveform data, you must configure the size of the FIFO elements equal to the size of the data you want to share. If both the network buffer and the RT FIFO are enabled, the network buffer must be at least as large as one FIFO element. Sharing data smaller or larger than the length you specify causes a memory allocation that affects determinism.
Note Waveforms contain variable-size variant elements that are not compatible with the Real-Time FIFO. Therefore, if you enable the Real-Time FIFO on a shared variable that contains waveform data, the variant element of the waveform data does not transfer.
http://zone.ni.com/reference/en-XX/help/370622K-01/lvrtconcepts/rt_projectvariable/#Single_Element_F...
'Hope it helps
Aurelie

Shared variable dataflow

Hello all,
I am using a shared variable to share a 2D array of SGL datapoints between two networked PCs:
PC-1 has the shared variable setup in the project as a Network-published variable using Buffering (size = 1 array, Array size = 20 elements).
PC-2 reads the shared variable using an array indicated with data binding to (PC-1). A colleague put the shared variable in a flat sequence with a wait state. I couldn't see any reason why this would work, so I removed the flat sequence. After that, I found that sometimes the array will be empty when it should have valid data. I put the flat sequence back and viola!, the program works normally.
Attached is a code snippet from PC-2 where the issue happens. ('Data' is the shared variable array'). Any ideas?
Message Edited by vt92 on 04-02-2008 10:04 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
Attachments:
no_joke1.gif ‏6 KB

Look like you have a race condition occurring. He probably extracts the data and waits for a 100 ms to have the next data ready. When you removed the sequence, you the 100 ms not occurrs concurrently and will be a bit shorter. The process writing to the data may not be fast enough to get the data ready for the next operation. or loop thus getting false data or the process has not completed to put the data in. the sequence guarantees, that you wait 100 ms to occur after the data read, whereas when you removed it, it can be any time within the 100 ms.

Unable to read shared variable in signal express

Dear all,
I am trying to read a shared variable with data type 'Array of Double Waveform' and the signal express gives a network variable error stating
"The data type of specified shared variable xxxxxx is not supported".
could any one explain why is this not supported or suggest a work around.
Munir.
Attachments:
Untitled-1.jpg ‏66 KB

Hi Munir,
the datatype you want to use is not supported in Signal Express. So if you choose this datatype you always get this error massage. As a work around I can recomment you to take the Double Waveform datatype this is supported, create a shared variable for each array element (waveform) and read this variable in Signal Express. This should help you out.
If you got any questions feel free to ask me.
Regards
TomBaum

Shared variable data type: Can I choose an array of a custom typedef, without making the array itself a typedef?

Hi all,
I'd like to pass an array of a cluster across my network. My cluster is typedef'ed, but I'd like to avoid polluting my project with another redundant typedef.
Is it possible to use the shared variable's "From Custom Control..." option with an array, without saving the array as a new .ctl file?
Solved!
Go to Solution.

Ah, I didn't realize you were using shared variables. I thought you were just considering it as another option along with TCP/IP or UDP or something like that. In this case, you would have to create a second custom control. This control would be an array with teh typedef cluster in it. No need to make this new control itself a typedef though. Sorry, I know you were hoping for a different answer. I doubt one file will really "clutter" your project though
CLA, LabVIEW Versions 2010-2013

Get data in a subreport based on a shared variable from the main report.

Goodd morning,
My question/problem is how to manage this scenario.
I am transfering 2 shared variables (pereiod from /period To, ) from the main report to a subreport and now i would like to get data in this subreport based on these 2 variables...
The problem is that i can not find the shared one in select expert icon...
Could anyone point me to solve this issue?
Thks for any help.
Jose Marin
Crystal Report XI SR3

Hello Jos,
I recommend to post this query to the [Crystal Reports Design|SAP Crystal Reports; forum.
This forum is dedicated to topics related to the creation and design of Crystal Report documents. This includes topics such as database connectivity, parameters and parameter prompting, report formulas, record selection formulas, charting, sorting, grouping, totaling, printing, and exporting but also installation and registering.
It is monitored by qualified technicians and you will get a faster response there.
Also, all Crystal Reports Design queries remain in one place and thus can be easily searched in one place.
Best regards,
Falk

Error Reading a Shared Variable Array

Hi,
I am having a problem reading an array of 20 unsigned integers from an Allen Bradley ControlLogix PLC with Labview.
I have set up a shared variable for this purpose. I have set the Data Type of the shared variable to ArrayOf Unit16. The Variable Type is Network-Published, and I have check the Bind To Source checkbox. I think my problem is in the shared variable path. I have tried the following with no success:
MyComputer\ControlLogixTags.lvlib\RsLinx\ProjectX\Online\Faults\Faults
MyComputer\ControlLogixTags.lvlib\RsLinx\ProjectX\Online\Faults\Faults[0]
MyComputer\ControlLogixTags.lvlib\RsLinx\ProjectX\Online\Faults\Faults[]
MyComputer\ControlLogixTags.lvlib\RsLinx\ProjectX\Online\Faults\
MyComputer\ControlLogixTags.lvlib\RsLinx\ProjectX\Online\Faults
I have created a simple vi for testing. I have wired the shared variable to an indicator which is an array of UInt16 items. When I run the vi, I get an error which says "Error 91 occurred at Variant to Data in Text.vi. Possbile Reason: The data type of the variant is not compatible with the data type of the input."
Does anyone have a suggestion as to what I am doing wrong?
Thanks in advance for your help,
Phil

Phil,
In order to determine that you can correctly communicate with your OPC server, I would suggest creating a shared variable bound to a single tag. It sounds as if you already have an RSLinx I/O Server in your project library. Now you can create a new shared variable and use the browse option to browse the items of your I/O server. Be sure to select a tag that has a known value such that you can verify successful communication.
Also, does your VI utilize a dynamic data conversion? The error code mentioned (error 91) is normally associated with this data type. Our next step will be to look at this VI once we can establish successful communication. I hope this was useful for you. Please let me know if I can be of further assistance.
Mike
National Instruments
Applications Engineer

How to create an array containing shared variable values

Hi
I am trying to programmatically create an array containing shared variable values and their names. I can get the variable names by supplying the process name to the get shared variable list function. How do I then read the value of all the shared variable items returned?
I have used a data socket open to open a connection to all variables when my program starts. I then use datasocket read on the opened connections to write to an array. This works fine until I try to write to one of the variables using a shared variable node. The variables writes can take from 4secs to 2 mins. When I remove the shared variable node again all is fine. Also when I stop using the data sockets, all is fine.
Is there a conflict between shared variable nodes and data socket writes to the shared variables?
Can anyone help? I cannot easily post example code because I am reading the variables from a Wago PFC (PLC) using OPC.

Hi
Sorry I forgot to mention the LabVIEW version, its 8.20. I have tried saving the shared variable node as a sub VI and it makes no difference.
Attached is a stripped down version of the software. You will not be able to connect to the IO server because it requires some Wago hardware and software. You may spot something I have done wrong with the I/O servers, variables or sub VI's.
The main program that runs is called 'HMI Engine' in the 'Framework' folder. There may be some other things in the project that aren't used in this example. I have removed all but the variable connection part of the code.
I hope someone can help!?
Thanks
Mark.
Attachments:
HMI Test.zip ‏144 KB

Group based on Shared variable

Hi Experts,
Can we create a Group based on Shared variable in subreport?

Hi Praveen,
A shared variable evaluates in Pass 2 and hence No!
You can't create a group on such formulas in the Main Report or the Subreport.
-Abhilash

Shared Variable based on Array of cluster

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