SACLAY GBAR COMMAND CONTROL

The GBAR experiment will be installed in 2016 at CERN’s Antiproton Decelerator, ELENA extension, and will measure the free fall acceleration of neutral antihydrogen atoms. Before construction of GBAR, the CEA/Irfu institute has built a beam line to guide positrons produced by a Linac (linear particle accelerator) through either a materials science line or a Penning trap. The experiment command control is mainly based on Programmable Logical Controllers (PLC). A CEA/Irfudeveloped Muscade SCADA (Supervisory Control and Data Acquisition) is installed on a Windows 7 embedded shoebox PC. It manages local and remote display, and is responsible for archiving and alarms. Muscade was used because it is rapidly and easily configurable. The project required Muscade to communicate with three different types of PLCs: Schneider, National Instruments (NI) and Siemens. Communication is based on Modbus/TCP and on an in-house protocol optimized for the Siemens PLC. To share information between fast and slow controls, a LabVIEW PC dedicated to the trap fast control communicates with a PLC dedicated to security via Profinet fieldbus.