CODESYS - the IEC 61131-3 automation software

question opc ua
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Author:  jbarrio [ Tue Mar 20, 2018 12:36 am ]
Post subject:  question opc ua


I have tried the opc ua server of codesys with runtime raspberry with uaexpert and it works without problem

But I tested it with two different scadas and both give me an error in the nodeid (CODESYS control for raspberry pi SL) both return BadNodeIdUnknown, there is some configuration to change this nodeID.

It is rare that two client opc ua return the same error.

With a client opc ua test, they work perfectly, and observed that these clients generate an XML schema that codesys does not generate, is there a possibility of this?



Author:  Edwin Schwellinger [ Tue Mar 20, 2018 11:40 am ]
Post subject:  Re: question opc ua


'two different scadas' - we try ro reproduce it if you send us links or more information to these products.
If you compare the NodeId between, OPCUA Expert and the non working scada, you could maybe get an idea
how to access.... ( I mean with the help of OPCUA expert)
Maybe this trick here helps to get the correct ... verbinden/
I have to say that it is anything but trivial how the NodeID is composed. But I found a great trick that saves a lot of time. What annoyed me is the fact that I could not copy the NodeID anywhere. In my tests, I had countless script errors that only arose because I had transmission errors copying out the NodeID (for example, NS4 | String || var | CODESYS Control Win V3 x64.Application.GVL.uiCycleCounter


Author:  jbarrio [ Tue Mar 20, 2018 11:53 am ]
Post subject:  Re: question opc ua

the scadas are a niagara and another b-scada, niagara needs a license but b-scada is free you can download and try without problem.

I'm going to try to see if I guess something with the help of an expert

thanks edwin.

Author:  jbarrio [ Wed Mar 21, 2018 8:28 pm ]
Post subject:  Re: question opc ua


After investigating, testing and spending some neurons.

I have managed to get one of the scadas even if it does not work to discover I can register the points with their full name (thanks a lot for the example edwin helped me a lot).

a question, there are tags that are defined by string and others that are seen by a number, all have that string and that number or depends on how the server is used or one system or the other?

Author:  Edwin Schwellinger [ Sun Mar 25, 2018 1:52 pm ]
Post subject:  Re: question opc ua


the NodeIDs on OPC UA could have differnet format:

Numeric, String, Guid, Opaque

the NodeID is the following:

typedef struct _OpcUa_NodeId
OpcUa_UInt16 IdentifierType;
OpcUa_UInt16 NamespaceIndex;

OpcUa_UInt32 Numeric;
OpcUa_String String;
OpcUa_Guid* Guid;
OpcUa_ByteString ByteString;

The ID is assigned by the server. Therefore, different IDs are mixed in the server.

Best Regards

Author:  Peter.skokanek [ Wed Jun 13, 2018 1:27 pm ]
Post subject:  Re: question opc ua

I need to Read/Write variables from Codesys to runing python script. I tested example OPCUA where is changing iConunter variable in Codesys project and the value of iCounter is printed by means of OPC UA client "". It works well. But I don't need print it I need to use this value in my python script. How can I extract value of iCounter variable?


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