.. _OPCUA:

OPC-UA Interface
================

The OPC-UA interface is provided by the :ref:`vnx.opc_ua.Server` and :ref:`vnx.opc_ua.Proxy` modules.

They allow to access internal modules via OPC-UA method calls,
as well as call methods on another OPC-UA server via a :ref:`LUA_script` for example.


Server
------

To enable the :ref:`vnx.opc_ua.Server` set the following config option:

.. code-block:: sh
	
	cd ~/pilot
	echo true > config/local/enable_opcua_server

The server will listen on the address ``opc.tcp://0.0.0.0:4840``.

By default the following options are set:

.. code-block:: javascript
	
	{
		"export_services": [
			"PilotServer",
			"MovechainHandler",
			"TaskHandler",
			"HybridPlanner",
			"GlobalPlanner",
			"RoadMapPlanner",
			"LocalPlanner",
			"PlatformInterface",
			"vnx.process"
		],
		"export_topics": [
			...
		],
		"use_authentication": true,
		"default_access": "USER"
	}
	
To add more modules and topics to the interface create a config file ``config/local/OPC_UA_Server.json`` as follows:

.. code-block:: javascript
	
	{
		"export_services+": [
			"AnotherModule",
			...
		],
		"export_topics+": [
			"another.topic",
			...
		]
	}


Proxy
-----

To run a :ref:`vnx.opc_ua.Proxy` which connects to another OPC-UA server
create the following config file ``config/local/opcua_proxy_map``:

.. code-block:: javascript
	
	[
		["OPC_UA_Proxy_1", "opc.tcp://127.0.0.1:4840"],
		...
	]

The above proxy will be available unter the module name ``OPC_UA_Proxy_1``, see :ref:`LUA_script` for examples on how to use it.


Data Types
----------

Primitive data types are directly mapped to their OPC-UA counter parts, such as ``int`` to ``INT32``, ``float`` to ``FLOAT``, etc.
``string`` is directly mapped to a OPC-UA ``STRING``. Arrays of said types are directly mapped to OPC-UA arrays.

Anything else will be converted to JSON and transported via a ``LocalizedText`` object, with the ``locale`` set to ``JSON``.