The implementation and application of statecharts in real-time system in high energy physics

In the Data Acquisition System (DAQ) of modern high energy physics experiments, the read out system which takes data from and transfers commands to the front-end electronic systems must be capable to meet the need of high-speed and real-time. In the DAQ of the Beijing Spectrometer III (BES III) project, the read out system is designed to be based on an embedded and real-time computer system. To define and construct such real-time systems, using statecharts is an effective approach. It is introduced to build the read out system in the cosmic ray test experiment of BES III Main Drifted Chamber (MDC). This paper presents an introduction of statecharts and illustrates several methods to implement statecharts.