DSC - OPC Connection - Can't read or write to tags

[vince.rolin]

I am working on controlling some motors over an OPC server.

The PLC is an M258, and the OPC server is CoDeSyS OPC DA.

When I use MatrikonExplorer, I can read the value of tags, and change their values as needed.

Using an evaluation version of NI OPC client, I could see the tags, but their value was marked as "unknown" with bad quality. In their properties, the value of the tags is given as "BAD VARTYPE".

I used DSC to add the codesys server to a library and imported all the relevant variables. When I try to read them in a VI, they give me error code: -1950679034, so that they have no value. And when I try to change a value, I can see that the value never changes.

I would greatly appreciate any help you can provide.

[natasftw]

http://www.ni.com/white-paper/6417/en/

Codesys isn't listed as a supported OPC Server.

[Mach4]

natasftw: The link you provide is to a list of systems that the NI-OPC Server supports.  That's not relevant to the original question.  

The issue is that the NI-DSC OPC _Client_ cannot communicate with a third-party OPC Server (CoDeSyS OPC DA).  If he can read and write to the PLC with another tool via the CoDeSyS Server, then the communication between Server and PLC is fine.  What doesn't work is the ability for the NI-DSC OPC Client to communicate with the CoDeSyS Server.  If CoDeSys is OPC compliant, any Client should be able to use it as a Server.  I'm running into the same issue with KepServer.  From what I've seen so far, the problems most often are caused by firewalls blocking the client, but even dropping the firewall is not helping me.  

Good luck vince.rolin; let us know if you find anything.