OPC UA architecture

[vix]

Even if the names are quite similar "OPC DA" is completely different from "OPC UA".

On NI website you can find some info on OPC UA, for example here.

For LabVIEW, DSC and Real-Time modules include "OPC UA" API.

Some years ago, Tomsaw asked about OPC UA interface in CVI (see here), but he didn't receive any detailed info.

Is there a way to develop "OPC UA" interface (client and server) with LabWindows/CVI?

I'm interested in NI or third-party modules or API.

[vix]

I suspect that OPC UA interface is not available for CVI... unfortunately.

But can someone from NI side answer to this question, please?

Thanks

[D-Cubed]

Hi Vix,

NI does not provide an OPC UA solution specific to LabWindows/CVI.

I'm curious, have you tried any of the open-source C solutions out there? In looking around, I saw this one ( http://open62541.org/ ) for example.

[vix]

Hi Daniel,

I didn't know about open62541 project.

I'm going to looking to this solution deeply in the next few weeks to see if this library is useful to me.

Thanks for having found this project

[vix]

Hi Daniel,

after some months I've just started the test on open62541 library but the compilation fails:

• under CVI 2010 SP1 it fails because of

#include <inttypes.h>
#include <stdbool.h>

The above files should be part of C99 extensions (supported by CVI 2010 SP1). I enabled C99 extensions but the compilation fails

• under CVI 2015 the compilation fails because of

#include <malloc.h>

I'm not sure this is a standard-C library so I don't know if this is a problem of either CVI or open62541 library

Are the above failures expected under CVI?

[vix]

On <malloc.h> not found with CV2015 I found this thread and it seems this is not a standard ANSI C header and so this should be a problem of open62541 library.

I'm going to investigate with open62541 developers.

[Jason-H]

Vix,

If there's anything we can do to help on the CVI side of things after following up with open62541, please let us know.

[vix]

I proposed a fix to open62541 library so that it can be recompiled with CVI/CLANG (waiting for acceptance of the fix).

From your side, it would be useful if you could use the library to supply a classic client/server example working in CVI 2015

[vix]

Hi Jason,

did you have time to create an example in CVI 2015 which uses open62541 library to develop a working client/server pair (with a minimal UI)?

[vix]

Hi Jason,

after deeper tests on open62541 library I found two unexpected behaviors:

• 'variable is uninitialized' and unions
• 'Designated Inits'

Could you help with them, please?