ANL, Argonne, Illinois, USA
The installation of a new Electron Beam Ion Source (EBIS) to the Argonne Tandem Linear Accelerating System (ATLAS) at Argonne National Laboratory requires a vacuum system capable of providing pressures in the region of 10-10 Torr. Historically, vacuum interlocks have been provided via analog logic chassis which are difficult to upgrade and maintain. In order to provide sufficient interlocks to protect high voltage components of the EBIS, a new programmable logic controller (PLC) based Vacuum control system has been developed and integrated into the rest of the accelerator supervisory control system. The PLC interfaces not only with fast acting relay based interlock signals but also with RS-485 based serial devices to monitor and control lower priority parameters such as pump speeds, vacuum pressure readout and set points, run hours and more. This work presents the structure and interface logic necessary to communicate with a range of vacuum gauges, turbo-molecular pumps and ion pump controllers. In addition, the strategy to interface vacuum control with the rest of the accelerator control system is presented.
