We are back in userspace. In this video I will show you how to add a method with two input and an outut parameter to an OPC UA server build with the open62541 library. To make it a little bit cooler, we will write methods to turn on and off two LEDs on a Raspberry Pi 3. Here is a link to the open62541 documentation: https://open62541.org/doc/current/tutorial_server_method.html Here is a link to my git repository, where you can find the sourcecode: https://github.com/Johannes4Linux/open62541-methods To use the software, you have to install: - open62541 library - wiringPi - gcc As a graphical OPC UA client, I use ocpua-client from the freeOpcUA's project: https://github.com/FreeOpcUa/opcua-client-gui