Feasibility study of a control system based on PLC and EPICS for the ESTHER combustion gas injection

The ESTHER laboratory will simulate spacecraft atmosphere re-entry conditions by generating a shock wave through the deflagration of a hydrogen, oxygen and helium gas mixture. The gas injection sequence into the combustion chamber must be precisely and safely controlled in order to prescribe the initial pressure in the two-stage shock tube and to avoid accidental detonations in any part of the system. In this work, a prototype control system setup using a Siemens PLC in an EPICS and CSS software environment is presented. An example application was developed, where a simple control sequence implemented on the PLC was remotely monitored and controlled by an operator interface. This setup was able to meet the control system requirements and the prototype served as the starting point for the development of the complete ESTHER gas injection controller.