JSUA — An OPC UA JavaScript framework

The OPC specifications define common interfaces towards process data servers for user interfaces, alarm servers, etc. in industrial automation. The hybrid profile defined in the latest OPC specification Unified Architecture (OPC UA) combines an efficient binary encoding of messages with a transmission over HTTP(S). This enables pure web browser-based OPC UA clients that do not need any additional software or plug-ins installed as requested by the industry more frequently. This paper therefore presents the OPC UA JavaScript framework JSUA that incorporates a JavaScript implementation of the OPC UA communication stack. Time measurements show the performance of JSUA on different devices and compared to a native OPC UA client implemented in C++.