ELT tracking local supervisors design and development status

The ELT Control System can be divided into the Central Control System (CCS) and subsystems Local Control Systems (LCS). At the heart of the CCS we have the High-Level Coordination and Control (HLCC) software which offers a single interface to the telescope towards the operators and instruments and coordinates the telescope subsystems. HLCC interfaces to the Local Control Systems (LCS) via the respective subsystem Local Supervisors (LSV). The LSVs are then responsible for interfacing to the different LCSs converting from the astronomical and user domains into actions and measurements in the individual device's domain. Following celestial objects, i.e. tracking, is done on three ELT LSVs, the Main Structure (MS), the Dome and the Pre-Focal Station (PFS) LSVs. HLCC distributes the target information and the involved LSVs compute periodically the trajectory setpoints using the CCS's pointing engine for their respective devices. The tracking also considers a dynamic pointing origin, used to cope with the fact that the instruments might not have a perfectly aligned center of rotation. Pointing models that consider imperfections and physical effects are used for the MS and PFS LSVs. The timestamped setpoints are sent to the corresponding LCSs and feedback is gathered using deterministic channels.