MAVIS: designing the interface between instrument control software and SRTC

MAVIS is the new MCAO Assisted Visible Imager and Spectrograph for ESO’s Very Large Telescope. It is intended to be installed at the Nasmyth focus of UT4 “Yepun” telescope and it is composed of two main parts: a multi conjugate adaptive optics module and its post focal instrumentation, an imager and an IFU spectrograph, both operating in the visible spectrum. The project is now in the final design phase and it is expected to be commissioned in 2030. In this paper we focus on the interface between the instrument control system software (ICSS) and the soft Real-Time Computer (SRTC). ICSS is in charge of controlling all the motorized functions, managing the scientific exposures, monitoring the status of the system and coordinating the sequence of operations; on the other hand RTC receives data from from the wavefront sensors (8 LGS and 3 NGS) to compute the corrections to be applied by the two post focal deformable mirrors and 8 LGS jitter mirrors. ICSS will be based on the new ESO ELT software framework, which is still under development; SRTC will be based on the new ESO RTC Toolkit, also under development. We present the first design of the common interface between ICSS and SRTC, focusing mainly on the communication processes (commands and data) and which are the most critical points we had to face.