Upgrading the ALS beamline equipment protection system: software development and implementation

The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory, a third-generation synchrotron light source, has been in continuous operation since 1992. The ALS beamline equipment protection system is being upgraded by replacing legacy end-of-life Modicon PLCs with Allen-Bradley PLCs. This paper presents the software architecture of the upgraded system, highlighting the Allen-Bradley PLC programming approach and the development of the EPICS database that integrates the protection system into the facility’s control system infrastructure.