ACPLT/RTE example project for OPC UA Server interfaces

This project shows how to write a specialiced interface class for the opcua library to utilize custom transformations from OV to OPC UA or to use OPC UA Companion Specifications.

Simple Demo "interface"

The repository contains a demo ov library, a demo fbd file, some screenshots and some boilerplate template files. The example fbd for the demo contains an OPC UA server from opcua ov library, a custom interface from this demo library and an example functionchart from the fb library, that is show in the following screenshot.

The example functionchart contains three input ports (In1Bool, In2Int, In3String) from different types. They are connected to an output port (Out1Bool, Out2Int, Out3String) of the corresponding type each. The fb connections are contained in the ExampleFunctionchart. The idea of the demo library is to change the generic transformation of fb functioncharts as shown in the next two screenshots.

The custom interface class in the demo library, which is derived from the abstract interface in the opcua library, contains a transformation, which is defined in trafo.c. Transformations are encapsulated in custom OPC UA nodestores. The demo transformation changes the OPC UA representation of every functioncharts generically by:

• removing some variables except for actimode
• creating two virtual (=only in OPC UA seen) folders: STATUS and OPERATIONS
• replacing output ports (which are own objects in OV) with OPC UA read only properties and collecting them under the STATUS folder
• replacing input ports with OPC UA methods inside the OPERATIONS folder with one parameter as kind of setter methods

Prerequisites

Before running the demo make sure:

• You can build this project according to ACPLT/RTE README and run an ov_runtimeserver
• You have an ACPLT/KS client to load the Demo.fbd, e.g. fb_dbcommands or iFBSpro
• You have an OPC UA client, e.g. FreeOpcUa Client GUI or UaExpert

Run the demo

• Start the ov_runtimeserver, e.g. via CLI:

  ov_runtimeserver -f test.ovd -s MANAGER -l stdout -c 10000000 --force-create -w ksbase -w kshttp -w TCPbind -w fb -w ksxdr -w opcua -w demo

• Load the Demo.fbd fbd via a KS client

• Start the OPC UA Server:

  • Optional: configure the /TechUnits/Server and /TechUnits/Server/Interface, e.g:
  • Change the Server.port to 16664
  • Change the Interface.entryPath to /TechUnits
  • Note: some variables can only be chaned if the OPC UA server is stopped
  • Set /TechUnits/Server.run to true
  • check that the server is started via /TechUnits/Server.isRunning

View the ov_runtimeserver from OPC UA Client:

• connect via an OPC UA client to opc.tcp://localhost:4840
• browse to 0:Root/0:Objects/1://1:TechUnits/1:ExampleFunctionchart

=> the transformed functionchart should look like this from an OPC UA client:

• Now you can play around, e.g.:
  • read the output properties beneath the STATUS folder
  • call a method, e.g. In1Bool to change the input (and after execution of the functionchart) also the connected output value (Out1Bool)
  • start (1) or stop (0) the functionchart by changing actimode
  • create other function charts or add, delete and change ports via KS (make sure to refresh TechUnits folder in the OPC UA client afterwards) and look how they are transformed
• Or you can change between the generic version and the version with the active demo transformation:
  • stop the OPC UA server from a KS client: set /TechUnits/Server.run to false
  • unlink /TechUnits/Server/Interface.server from /TechUnits/Server.interfaces
  • start the OPC UA server again: set /TechUnits/Server.run to true

Demo with nodeset and data types

The demo library contains a second example with a interfaceTypes class and corresponding trafoTypes transformation functions, as well as a very simple generated nodeset file with two custom datatypes:

• Actimode: an enumeration with values ON, OFF, UNLINK, ONCE and CATCHUP that should represent the actimode of fb tasks.
• Identifier: a struct that consists off two integers idH and idL (ids of OV objects).

To test the demo with nodeset and data types follow the section Run the demo, but load the DemoTypes.fbd instead of Demo.fbd. The ExampleFunctionchart is named Functionchart here and its transformed version should look like this:

Nodeset generation hints

The simple demo nodeset is already compiled to open62541 C code, so typically you don't have to generate it. But here are some hints in case you need to recompile (e.g. update to new open62541 version). Make sure that the open62541 version matches the submodules version or execute the parsing process from the submodule. The nodeset files were generated by the open62541 parser from the nodeset files with the following command (from project dir):

python3 rte/syslibs/opcua/open62541/tools/nodeset_compiler/nodeset_compiler.py --types-array=UA_TYPES --existing rte/syslibs/opcua/open62541/tools/schema/Opc.Ua.NodeSet2.Reduced.xml --xml demo/nodeset/nodeset.xml nodeset

python3 rte/syslibs/opcua/open62541/tools/generate_nodeid_header.py demo/nodeset/nodeset.csv nodeset_ids NS2

python3 rte/syslibs/opcua/open62541/tools/generate_datatypes.py -c demo/nodeset/nodeset.csv -t demo/nodeset/nodeset.bsd --namespaceMap=2:http://github.com/acplt/rte_opcua_example/Nodeset/ nodeset

Replace the following generated files in source and include directories of the demo library:

• nodeset.c/nodeset.h
• nodeset_generated.c/.h
• nodeset_generated_handling.h
• nodeset_ids.h