OPC UA in CVI

Dear CVI experts!
What do you recommend to connect to an OPC UA server ?
I already asked the NI technical support and the response was, at present it would be the best to use a third party product ...
Do you have any other suggestions ? I was used to use the functionality of CVI for "classical" OPC (and Netvars and Datasocket and ...).
It was so easy ...

Dear Matijas,
thank you for your replay!
First thing is: It was about LabWindows/CVI - so I think VIs is in LabView - isn't it ?
I tried the "classical" approach, but I don't even have the possibility to select URL etc. because "OPC UA" is not COM based. It's a complete different technology.
Best Regards,
Tom

Similar Messages

Problem to connect with OPC Server opc.sinumerik.machineswitch using DS_Open

Hi,
I want to connect to an Siemens OPC server type opc.sinumerik.machineswitch using DS_Open calls (CVI 6.0) to read few tags. Running my client software (as well as the NI- sample test client) locally on the same computer as the server the connection works and I can access the tags.
Running the client-software on a remote PC then the DS_Open call "hangs-up" (not even an error message). All the DCOM settings etc should be ok, since I can access the tags using the Siemens Client OPC-Scout as test client.
I have used the same calls in several previous applications and it works with other servers (Bachmann, WinCC), so I am pretty sure that I use the correct URLS etc.
What can be the reason for a specific incompatibility?
Any idea is highly appreciated.
Cheers,
Ronald

Hi Roland,
as experience shows, Remote DataSocket is hard to implement.
The best way to implement this communication is the following:
First of all, check the DCOM -Settings
Using OPC via DCOM with Windows XP
http://www.opcfoundation.org/DownloadFile.aspx?RI=326
Use the “NI-OPC Server” to create a tunnel between the Siemens OPC server and your PC.
Install the NI-OPC Server on your PC and use the “OPC DA Client Driver” to access the tags on the Siemens OPC server.
After that you can access the created tags in the NI-OPC Server with CVI and DataSocket.
Please download the NI OPC Servers Evaluation-Version to test communication.
NI OPC Servers
http://sine.ni.com/nips/cds/view/p/lang/en/nid/209059
Download NI OPC Servers Evaluation
https://lumen.ni.com/nicif/us/evalopc/content.xhtml
Regards
Ulrich

Ethernet/IP in LabWindows?

Has anyone done anything with Etherent/IP within LabWindows? Is there a third-party library that will accomplish this?

Hi Hendra,
We have an ethernet/IP toolit but it doesn't have a c-api.
you can:
1) look at wrapping the labview toolkit in a dll. We have done so sucessfully for other applications, like Veristand.
2) Use an OPC server solution, which is slightly more complicated. You need to
a) Use NI OPC servers, which are a part of the DSC module, to connect to the PLC. We should have an OPC server that supports an ethernet/ipc connection for your PLC. I would be your PLC supports other types of connections also.
b) Connect to NI OPC servers from CVI through data sockets.
OPC servers will be pretty slow performance-wise but they may have other advantages, such as easier debugging and configuration, that give them an edge.
Either way post back what works for you. I feel people get lost trying to implement systems like this and having a working system outlined would help immensely.
Jesse Dennis
Design Engineer
Erdos Miller

Documentation on How to Develop an OPC Client Using LabWindows/CVI?

What documentation is there on how to develop an OPC client application using LabWindows/CVI? What tutorials, if any, are there? What reference manuals, if any are there?
I am completely new to LabWindows/CVI. I will be starting soon with the tutorial, "Getting Started with LabWindows/CVI". However, our application needs to communicate with an RSLinx OPC Server. Any documentaiton on how to learn to do this would be very much appreciated.

http://www.ni.com/white-paper/4626/en/ Just did a quick google and this came up, Labwindows CVI and Labview are quite different but I usually look at Labview examples then try take the general idea from the example and apply it in CVI, hope this helps

How can I create an application in MSVC 6.0 to access my FieldPoint modules with CVI 5.0 libraries?

I have an application in CVI 5.0 that works. I am trying to export that so I can develop in MSVC. I need none of the UI provided in CVI, all I need are the simple FieldPoint commands provided in FieldPoint.obj. I have been stumped on this for weeks. I would write my own OPC client but the interface isn't even documented on what commands I would send if I did have an interface. I would prefer just to use the CVI libraries in MSVC 6.0. When I call the FP_Open function the program crashes with an RtlSizeHeap error.
Thanks,
Chad

In theory, creating a dll that encapsulates the FieldPoint functions should work in MSVC. However, National Instruments has not tested MSVC interface, nor have we publicized that this type of setup will work, therefore making support unavailable. The other reason for why we do not offer support of FieldPoint in MSVC is that we have not seen a demand for such an interface. Therefore, I recommend that you create an OPC Client that communicates with the FieldPoint OPC Server. One example of such an OPC Client in MSVC is to use Datasockets, found in ComponentWorks++. You can find this example at the following web site:
http://zone.ni.com/devzone/devzoneweb.nsf/opendoc?openagent&8FEAB5F73CFB68278625683A000B06ED&cat=7CDA3E51FEFC4AA2862568B80071A1E2
If you are using the
serial network module (FP-1000/1001), you can communicate with the FieldPoint modules using the Optomux protocol. For a complete listing of the Optomux commands refer to the FP-1000/1001 Programer Reference Manual located at the following web site:
http://digital.ni.com/manuals.nsf/caba5d53e9b015a186256793004eebb7/bf97516ca18eee728625665e0063594e?OpenDocument
Best Regards,
JohnM

OPC instance deadband

DeadBand—Sets the percent of change within a range that a value from the OPC server must change before the OPC server communicates the value to the Shared Variable Engine.
I can't understand how OPC Server relize data range for different OPC items, where it can't see the range we set for each variable in shared variable configuration dialog box.
I will appreciate any help.

Hi Maryam,
Can I just clarify your question: are you asking how you configure the deadband value of your OPC server?
In order to be able to provide you with instructions on how to do this I need to know what you are using:
What OPC server are you using?
Are you trying to use the shared variable engine as an OPC server?
Have you got the NI Industrial Automation OPC Servers CD?
Or have you got a third party OPC server? - If so which?
Also are you using LV DSC to subscribe to the OPC?
If not what are you using? Datasocket? NI Lookout?
If you are using LV DSC what version are you using?
What are you using the OPC server to communicate with?
PLC? RTU? Hardware?
Via what client are you trying to communicate?
Are you using a software based client?
If so what piece of software are you using? and what version of the software?
LabVIEW? LabWindows/CVI, Measurement Studio?
Many thanks
Emma Rogulska
NIUK & Ireland

Connect LabWindows/CVI to Opto22

I would like to connect the hardware of Opto22 to the software of
LabWindows/CVI. I thought of using OPC but I don't understand really
how to setup an OPC server. Is there another way to connect these 2
items using a driver of maybe DDE? I quite new in these things so
forgive me if I ask stupid questions.
Sent via Deja.com http://www.deja.com/
Before you buy.

Hi nqn,
There are actually two conversion wizards that CVI offers with regards to integrating with Visual C++. You can read about them in the Integrating LabWindows/CVI with Microsoft Visual C++ KnowledgeBase. The only problem is that we don't have conversion wizards available for Visual Studio 208. We only have conversion and project wizards available for Visual Studio 2005, Visual Studio .NET 2003 and Visual Studio 6.0. I will say that we are planning on creating wizards for Visual Studio 2008 but this is several releases away. With that said, I would suggest that you submit a product suggestion so we know people are wanting this.
So for right now, I would suggest using the conversion wizard in Visual Studio 2005 and then just upgrading that project to VS 2008.
Best Regards,
Jonathan N.
National Instruments

Connection to server OPC NI

Hello,
I need help, I try to connect a software developped with LabWinows/CVI 9.0 to the opc server of National Instrument.
The tag is "opc://localhost/National Instruments.Variable Engine.1//./QGAPro/5_2" or "opc://localhost/National Instruments.Variable Engine.1//./QGAPro/5_4" for example.
But the program returns "Error: Can't add item to OPC Group. The item ID is not defined in the server address space or no longer exists in the server address space."
I can check the tag with client opc like :
How can I know where is the problem please?
Do you know where is the problem?
Thank you.
Bye. Karine.

You can find below a piece of code.
I can connect to the server OPC with a client test, but I can't in my program.
char opc_target[] = { "opc://localhost/National Instruments.Variable Engine.1//./QGAPro/            " };
static DSEnum_Status status_inline = DSConst_Unconnected;
static DSHandle dsHandle[512] = { 0 };
static void ShowDataSocketError(HRESULT errorCode);
/* This is the callback function for the DataSocket */
void CVICALLBACK DSCallback (DSHandle dsHandle, int event, void *callbackData);
void fieldbus_init(void)
    HRESULT hr = S_OK;
                char chaine_temp[50];
                int i, j;
opc_target[65] = '\0';
                strcat(opc_target, "5_2");
    hr = DS_Open (opc_target, DSConst_ReadAutoUpdate, DSCallback, NULL, &dsHandle[0]);                  //=> hr : « Opération réussie »
void DSCallback (DSHandle localDSHandle, int event, void *pUserData)
    HRESULT hr = S_OK;
    char message[1000];
    switch (event) {
        case DS_EVENT_DATAUPDATED:
            break;
        case DS_EVENT_STATUSUPDATED:
            DS_GetStatus (localDSHandle, &status_inline);
            hr = DS_GetLastMessage (localDSHandle, message, 1000); //=> message : « Can't add item to OPC Group. The item ID is not defined in the server address space or no longer exists in the server address space. »
            break;
    return;
I can't modify tags because this is another software that generates and which is developed by another company.
I have to read these tags to retrieve the associated values (values of a gas analyzer).
Can you help me with these informations please?
Thank you!
Karine

DataSocket & OPC

We have a Flywheel which sends data via an RS-232 connection to a serial port
on a PC, where LabWindows/CVI resides. This PC is connected to the corporate
intranet.
My question is: how can other OPC clients on the intranet access the data
that resides in the LabWindows/CVI PC that acquires data from the Flywheel?
I have heard that DataSocket will allow this, but is it OPC compliant? Are
there any tutorials that I could be pointed to for finding out how to share
this data w/ OPC clients?
Thanks!
Dennis.

Hello Dennis,
DataSocket does allow you to connect to OPC servers. You may find the information at http://www.ni.com/opc of interest, specifically the link to "ComponentWorks DataSocket".
For extensive information on OPC compliance and programming with DataSocket, try the following URL: http://zone.ni.com/
Then click on RESOURCE LIBRARY >> LABWINDOWS/CVI >> CONNECTIVITY >> DATASOCKET >> GENERAL
I hope this online information fully answers your questions.
Jeremiah Cox
Applications Engineer
National Instruments
http://www.ni.com/ask

OPC Server does not update data value

Hello,
I have a problem with a program that uses an OPC server to comunicate with a PLC.
It happens randomly, when I update the data, i cannot see any patern, sometimes it happens quickly, sometimes it takes longer...
The data socket is declared like that:
hr = DS_OpenEx ("psp://localhost/Server/Automate.405466", DSConst_WriteAutoUpdate, NULL, NULL, DSConst_EventModel, TIMEOUT_OPC_mSEC, &ecr_MW5465);
And is update like this:
hr = DS_SetDataValue(ecr_MW5465, CAVT_SHORT, l_buf, 1, 0);
The function does not return any error, but the value is not updated server side.
Lookout version is 6.6, the program is made with CVI 8.5.1 and communication is in ethernet modbus. I do not know if further details could be useful.
Thank you.

Fred,
Can you read the value being updated directly from the OPC server? Usually you can just view the values and see if they are updating.
The next thing to check would be to use the shared variable monitor to see if the variables that are bound to the OPC server are updating. It is under Tools >> Shared Variable >> Variable Manager.
Also, when you have the program running, do you get any type of error from reading the shared variable? If you are seeing an error, it would give us a little more insight into what is going on.
Brian Coalson
Software Engineer
National Instruments

Labwindows/CVI and Android

Hello,
I work in Labwindows/CVI on Windows XP for the moment, I developpe a software and I would like to know if it will be possible to make a software, the same that this one to run on Windows, which runs on Android please ?
My software uses a SQL database (SQL Server) and an OPC Server (Phoenix Contact).
If it's possible, how can I do to create this application and install on a tablet for example?
I just know that a "NI LabWindows™/CVI Run-Time Module for Linux" exists, but I don't know if this module allows me to install my software on a tablet...
Thanks.
Bye Karine

In addition Android programs are normally written in Java, which has nothing
to do with CVI. But I read a tutorial some time ago that showed how to
compile C for Android. So at a very basic level of a pure ANSI C program
with no (or duplicate) user interface, it is possible.
Guillaume Dargaud
http://www.gdargaud.net/

Cannot display square root symbol in cvi

I don't understand why this would be an issue, but if I'm writing in the source window (with the default font of NIEditor), I cannot display a square root symbol "√" - every time I type alt+251, I get "v". Ok, not a huge deal in the source window, but it is a big deal if THAT is what's being stored in a string variable I'm writing out to a file. Additionally, if I use the following to format a string:
"Fmt(setpointUOM, "%s<W%cT/P3", 251);", then setpointUOM = "WüT/P3". If I display this variable in a string control, it displays as "W√T/P3", which is correct, but if I use it in a Text Box or save it to a sql database, it displays "WüT/P3" which is unacceptable.
I've tried changing the fonts but nothing works or I get even stranger results. I've been dealing with/ignoring this since CVI7 and I'm currently at CVI10. Thanks for any help.
Solved!
Go to Solution.

The difference in the display between W√T/P3 and WüT/P3 has to do with the character set that you select for the UI control. From what I can tell, only the OEM code pages map the √ symbol to character 251, so if you want to see √ for that character, you should pick the OEM character set, in that control.
Entering √ with the keyboard in a CVI window seems like a much more problematic task. When you type Alt+251 on a CVI window, the keyboard driver is converting the 251 to 118 (the letter v). I don't know why it does that, but I noticed that the code that it converts 251 to varies, depending on your input language (which you can change in Control Panel>>Region and Language>>Change keyboards or other input methods). When english is selected in the language bar, it converts it to 118. With other languages, it converts it to other codes. I tried entering the unicode value for √ directly, which is Alt+221A (to enter unicode characters using the keypad, you have to follow the steps described here). But it didn't work. It still converted it to 118. I suspect the keyboard driver is doing this because it tries to map 221A to some symbol that is valid in the code page that corresponds to the input language, isn't able to, and picks what it thinks is the closest match.
In lots of other applications (but not all) you can type Alt+251 or Alt+221A and it works just fine. This is because those applications accept unicode characters directly. Unfortunately, CVI isn't one of them. It uses code pages (a.k.a. character sets, or multibyte sequences) instead of unicode, and symbols don't have a universal meaning; they depend on the code page.
Even if all this were not an impediment, you'd still run into the problem that in CVI 2010 you cannot change the font of the CVI source window to use an OEM character set. So, you'd still see it displayed as a v or a ü. In CVI 2012 you can change the change it, and so if you were using CVI 2012 you could conceivably use the clipboard to paste the √, but there is a bug in CVI that is preventing OEM characters from being pasted correctly (I realize the description says that it affects tree tooltips, but it's also generally affecting clipboard operations of some less commonly used character sets).
So, to make a long story short, I think you should continue entering the code directly with the Fmt function, at least until this bug is fixed. And make sure that all UI controls that need to display this string are using the OEM character set.
Luis

Using Excel with Visual C++ 6.0 (need a graph control that behaves as much like the one in CVI as possible)

I hate to beat this to death but I was unable to find a
clear answer to this question. Does NI provide Excel control from within
Visual C++ 6.0?
I read that NI supports the ANSI-C library only for Visual C++ 6.0 users:
Thread : "Re: Benifits of using measurment
studio for VC++ 6.0?"
NI REP : drohacek
Quote : "we made the decision to support Visual
C++ 6.0 users only through the ANSI-C interface and not through the Measurement
Studio MFC-based class libraries."
If there is a suggested way of controlling Excel from within Measurement Studio
for Visual C++ 6.0 then I’d love to know it.
If not, can a plain statement be made basically stating that if you want
to control Excel you can’t use a Visual C++ 6.0 environment even with Measurement
Studio support?
With .NET of course you can just decide to have Excel support added during
project creation. CVI can act as an ActiveX server and easily control
Excel just by building off the examples shipped with CVI. I see that
there is support, using the Measurement Studio for Visual C++ 6.0 Project Wizard,
for taking existing CVI projects and converting them to Visual C++ 6.0 projects
or for calling CVI libraries from a .dll from within Visual C++ 6.0. I suppose I could do the work
in CVI and then convert the project but I'm so deeply tied into all my MFC calls that I don't see
how I can cleanly include the CVI libraries into my existing VC++ 6.0 projects.
What I'm really after here is a visual graph control like the one in CVI that I
can use from Visual C++ 6.0. I purchased a 3rd party graph control for use
in VC++ 6.0 that works well but isn't really visual. I mean you can't
enter any values in it until you run the program and fill it out programmatically.
Then you can see which columns are two narrow, quit the program, adjust the
column width of your now empty control, and repeat, until you get the thing
looking the way you want. If I could call into Excel from within Visual
C++ 6.0 the way I do from within .NET
then I could use Excel to hold the table and just read in the values into my table
control at run time. Basically I'd use Excel as a visual development tool
for all my tables.
I do all my coding from within CVI and Measurement Studio for Visual C++
6.0. I'd use CVI for everything if I didn't depend so heavily on certain
outside controlled C++ .dll's. Could you please suggest then what I can
do to get Excel support for Visual C++ 6.0?
Last question :
Is there any plan to ever have a NI table control like the CVI table control for
use in Visual Studio? One that you can
completely set up before you do any compiling?
I imagine that the way Microsoft sets up their environment makes this idea impossible. Otherwise someone would
have come up with a truly “visual” table control before now.
Thanks,
Grant
Grant M. Johnson
Project Engineer
LECO Corporation

Hello Grant
You can most certainly use Excel with VC++ 6.0. Measurement Studio won't provided you with any classes to talk to Excel in VC++ 6.0. This is because Excel allows control via Automation and you can use its automation API to do anything you need with Excel. This is what CVI uses as well.
You can see this MSDN article on how to set this up. This mentions VC.NET, but it should work the same way.
Here is one that talks about VC 6.0 and Excel.
Here is a code project article about this.
Even with .NET, you have to do thru the Excel Automation support. Excel started shipping with Primary Interop Assemblies (PIA) which are .NET wrappers about the Excel Automation object model. C++ Automation is definetely not as nice as .NET, BTW
See this document for more information about the Excel object model.
I would not recommend using the CVI Excel libraries if all you want to use them for is Excel automation. You will end up creating un-necessary dependencies and go through extra layers that way. You can make calls straight to Excel from VC++ without requiring CVI.
One quick observation about your excel approach. If you decide to use Excel as your table, you might be requiring everyone who uses your application to have Excel installed on their machines. Just wanted to make sure this was acceptable to you.
Have you looked at the Datagrid Activex control, which is one of the common controls that ships with Visual Studio? You can add it to Visual Studio by right-clicking and picking it from the list of installed activex control. If you have not already, you should check it out.
Microsoft has made significant improvements in the number of controls they provide with .NET. They have a Datagrid control that seems to be what you need.
Measurement Studio did add some high level classes for Excel and Word Automation that simplify some common tasks, but these exists for VS 2003 C++ and VS 2005 C++, not for VC 6.0. Underneath, we end up using the same Excel automation classes, so you can easily setup something similar for VC 6.0. Plus you can find alot of references online on how to use the Excel Automation object model with C++.
We currently have no plans in Measurement Studio to create a table control unfortunately. I am assuming when you said graph, you actually meant table, since Measurement Studio already provides a ActiveX graph controls for VC++ 6.0 that is very similar to the CVI graph.
On a side note, VC++ 6.0 is really really old. Have you considered upgrading?
To summarize
- Yes, you can use Excel with Vc++ 6.0 without mstudio.
- Try using the Datagrid Activex control if you just need a table.
- Measurement Studio provides high-level excel and word classes for VC++ 6.0
- Measurement Studio provides a graph control for VC++ 6.0 which is very similar to the CVI graph.
- Measuremnt Studio does not have a table control.
- VC++ 6.0 is really really old. Have you considered upgrading?
Bilal Durrani
NI

Visual Studio or LabWindows/CVI?

I have a bit of a dilemma.
I currently own Visual Studio 2010, IMAQ Vision Development Module 2013, and Measurement Studio (not sure of version). I currently do all of my programming in VB.net. Because IMAQ VDM is stuck in .Net framework 3.5 and there will be no further .net development by NI, I need to plan for the future. My applications need run on Win 8, 9, 43, or whatever my company decides to migrate to from Win 7.
My understanding is that the NI modules I currently own will work with LabWindows/CVI. Correct? I also believe I can use them with C++ using the VS IDE. Is this also correct?
Within my applications I do a lot of interfacing with Excel, writing text files, and interfacing to non-NI devices (cameras, DAQs, scanners, etc). I am able to do these things pretty easily using VB.net using vendor-provided SDK's.
Therefore, my question is this...given the investment I have in software already, do I gain anything by migrating to LabWindows/CVI? What do I lose?
I should point out that regardless of the path I choose I will need to bone up on my programming skills in the corresponding language.
Thanks for all your help!

Hello Steverino!
Here are some advantages when using LabWindows/CVI over Visual Studio, which make the product more suitable for various industry-related applications:
You are correct, LabWindows/CVI integrates with the NI platform: NI hardware and software, like TestStand or LabVIEW (e.g. debugging source code from one software to another, seamlessly).
NI hardware and third-party hardware connectivity.
OpenMP support.
CVI integrates with intrument control.
CVI Run-Time benefits from User Protection.
Run-Time checking (e.g. for uninitialized variables).
Scientific User Interface Controls and GUI Editor.
Advanced debugging capabilities:
Remote debugging support from ADE.
Real-Time debugging support from ADE.
Memory leak detection using the LabWindows/CVI Resource Tracking Window.
Just-In-Time debugging.
Deployment: build custom installers and patches that you can ship as stand-alone easy-to-use installers.
LabWindows/CVI libraries: Advanced Analysis, Toolbox, Connectivity (Network Variables, Network Streams, DataSocket), etc.
Support for LabWindows/CVI Toolkits: SQL Toolkit, Vision, PID, RT.
Regards,
- Johannes.

How to read enumerated values from an OPC server via Datasocket

Hi Labviewers,
I am using LV8.2 and I am trying to find if it is possible to read enumerations from an OPC server via Datasocket, not just the values.
I can successfully read a value for an OPC server via Datasocket and I get a value for example 3, is it possible to get the enumeration/string that corresponds to this value i.e. "Open".
Many thanks in advance
Dimitris

Hi Sarah,
With the input type as variant I get the following response:
1                                     <-This is the current numeric value of the parameter
4 Attribute(s):
   'Quality' -> 192
   'TimeHigh' -> 29861723
   'TimeLow' -> -665408304
   'Timestamp' -> 39.238E+3
With the Input set to         Enum constant I get no values or strings coming back. With the Input set to             Ring constant I just get the numeric value
Dimitris

OPC UA in CVI

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