JET CODAS - the final status

Abstract

The JET Control and Data Acquisition System (CODAS) has stood the test of time and seen us through to the end of JET plasma operations in 2023. The system architecture has remained largely un-changed over the last decade or so although many new diagnostics and control systems have been added and the volume of data collected has grown massively. CAMAC remains at the heart of the system, particularly for continuous acquisition and control for much of the traditional, stable parts of the system. However, most of the newer diagnostics and control systems are network attached. The CAMAC interface was changed, about a decade ago, to remove the serial highway driver from the subsystem host so that the subsystem hosts could be virtualised and run on more powerful Oracle/Sun hosts, with the Serial Highway driver running on legacy sub-system host network attached. Other significant changes have been the development of a standard, web-based interface for control and data acquisition for diagnostics, the adoption of EPICS for several diagnostics and plant control along with integration into CODAS and the adoption of the ITER SDN protocols over ethernet to supplement the original ATM based real time control infrastructure.

These developments were driven by the increased monitoring and machine protection requirements for the ITER Like Wall and the enhanced requirements for the high power Tritium Campaigns (DTE2 and DTE3). The latter, including significant expansion of the neutron and gamma diagnostics, along with expansion of the Tritium introduction systems and enhanced control systems. Towards the end of plasma operations, the requirement for the Laser Induced Desorption with Quadrupole Mass Spectroscopy (LIDS-QMS) involved significant development work to incorporate the associated control and data acquisition systems together with pushing the mode of operation for JET Pulses. At the very end of plasma operations, the requirements for long pulse operation also pushed the pulse operating mode. We now progress to Decommissioning and Repurposing JET and CODAS continues to be adapted to support the diminishing number of systems required to support the plant that is still operational and support diagnostic calibration later this year.