The ELT primary mirror is a 39m diameter concave mirror composed of 798 mirror segments. Each mirror segment is equipped with edge sensors, position actuators and a surface deformation warping harness, independently controlled by their backend electronics. The controllers are mounted in cabinets grouping up to seven segments. Each cabinet contains a network switch and a PLC for power control, telemetry and auxiliary tasks. There are in total 132 cabinets, named segment concentrators, grouped in six sectors. This constitutes a system of more than 2600 networked endpoints, including micro controllers, PLCs and network switches, to be controlled and supervised.
The M1 Local Control System (LCS) is the subsystem of the ELT responsible for the monitoring and control of M1 segments. Its main goal is to enable the phasing of the M1 mirror to compensate for the presence of disturbances such as changing gravity vector, thermal expansion and wind forces. M1 LCS will provide a reliable and deterministic infrastructure to collect edge sensor and position actuators measurements and to distribute new position references at a frequency of 500 Hz. In addition, the software is responsible for devices synchronization, monitoring, configuration management as well as failure detection, isolation and notification.
The M1 LCS passed its final design review and the development commenced. The present paper summarizes the M1 LCS software design, including adopted patterns and technologies, and the current development status.