Real-Time Data Transmission Method Based on Websocket Protocol for Networked Control System Laboratory

This paper introduces a real-time data transmission method based on websocket protocol for networked control laboratory. Networked Control System Laboratory (NCSLab) is one of revolutionary online laboratories, which effectively solves the problems of inadequate experimental conditions and limited resources in experimenting education. NCSLab provides a solution to remote online control laboratory, including more than 26 experimenting platforms and flexible monitoring pages to show the control data and procedure. To maintain the real-time experimental display, central web server should send real-time data rapidly. A reliable and speed data transition between clients and servers is picked during the experiments in this paper. Given by Hyper Text Markup Language 5 (HTML5), websocket protocol, a protocol for full-duplex communication over a single TCP connection, simplifies the data exchange between clients and servers. The issues of control overhead, real-time performance, binary support and instability are tackled in NCSLab. The conditions and implement of websocket are explained in detail. At the end of the paper, a ballbeam system experiment platform is selected to illustrate the procedure of websocket communication.