OPC UA information model, data exchange, safety and security for IEC 61131–3

Data exchange, safety and security are required in many measurement and control systems in which programmable logic controllers are used in recent days. In this paper, we will describe the IEC 61131-3 software model at the first, and then introduce the method to translate this model to the information model of OPC UA. We will also mention that the translation between the models will be based on the each XML schema easily. Next, we will explain the safety software Function Blocks (FB) defined by PLCopen and show that the safety software applications can also be easily represented by the information model and their data can be shared by the monitoring systems. Finally, we will discus the security of PLC programming using OPC UA.