Design and implementation of a control system for process cooling water with a temperature accuracy of 25±0.1℃ based on HC900

[Background]: The electron gun of the Shanghai High Repetition rate XFEL and Extreme light facility (SHINE) needs many necessary conditions to generate high-quality electron bunches. The stability of the temperature of the electron gun body is one of the necessary conditions. [Purpose]: In order to meet the water supply temperature and accuracy of the electron gun system at 25±0.1℃, so as to reduce the impact of thermal expansion and deformation on the quality of the electron beam. [Methods]: Based on Honeywell's HC900, a process cooling water control system is designed. The main equipment includes high-precision temperature sensors, high-precision control valves, and three-phase in-line electric heaters. The design scheme is implemented by using advanced PID algorithms and the upper-layer monitoring software EBI. [Results and Conclusions]: After precision testing, this control system has abundant control strategies. The precision of the water supply temperature reaches 25±0.1℃, which can meet the current needs of the electron gun.