X2OPC is a Python implementation of the XPath to OPC UA translator.
Authors: Max Kocher, Johannes Theissen-Lipp, Patrick Sapel, and Mauritius Schmitz.
- Python3
- A running OPC UA server (e.g., the Prosys Simulation Server)
To run the files, fileAnalysis.py and OPCtranslator.py must be in the same folder.
To extract the address space of the OPC UA Server you have to execute the file extractor.py.
You have to specify the url of the OPC UA server in line 175 like
url = "opc.tcp://...:53530/OPCUA/SimulationServer/"and the path of the output file in line 179 like
path = 'D:\\Downloads\\Files\\OpcExport.txt'After the execution the file OpcExport.txt is created.
The XML image of the export is created with the fileAnalysis.py file.
To run the file, the path of the OpcExport.txt file must be specified in line 9 like
open('D:\\Downloads\\Files\\OpcExport.txt', 'r').read().split("\n")and the path of the XML file to be generated must be specified in line 419 like
file_object = open('D:\\Downloads\\Files\\OpcExport.xml', 'w')After XML expressions have been created, they can be transformed to OPC UA in the file OPCtranslator.py.
For this purpose the url of the OPC UA server must be specified in line 290 like
url = "opc.tcp://.....:53530/OPCUA/SimulationServer"The following table describes ten axes and their counterpart in OPC UA:
| XPath | Function |
|---|---|
| child | child(client, connected, nodeList, offlineList) |
| parent | parent(client, connected, nodeList, offlineList) |
| ancestor | ancestor(client, connected, nodeList, offlineList, rootnode) |
| ancestor-or-self | ancestorOrSelf(client, connected, nodeList, offlineList, rootnode) |
| descendant | descendant(client, connected, nodeList, offlineList) |
| descendant-or-self | descendantOrSelf(client, connected, nodeList, offlineList) |
| preceding | preceding(client, connected, nodeList, offlineList) |
| following | following(client, connected, nodeList, offlineList) |
| preceding-sibling | precedingSibling(client, connected, nodeList, offlineList) |
| following-sibling | followingSibling(client, connected, nodeList, offlineList) |
The client parameter references the server specified by the url.
The parameter connected can be True or False and indicates whether the server or the server's export is used.
The parameter nodeList contains a list of NodeIds on which the function is executed.
The offlineList parameter contains the information of the server's export and is defined in line 292.
The rootnode parameter contains the nodeId of the server's root node.
The visualizations folder contains the code to generate all the illustrations shown in chapter 5. Each file can be executed independently and already contains all the necessary information.