A standard framework for developing instrument controllers for the ATST

The Advanced Technology Solar Telescope (ATST) is a 4-meter solar observatory under construction at Haleakala, Hawaii. The simultaneous use of multiple instruments is one of the unique capabilities that makes the ATST the premier ground based solar observatory. Although the operation of the instruments and the data collected varies widely across the ATST instrument suite, the basic control functions and data recording capabilities are similar. Each instrument must be capable of controlling its devices, mechanisms and hardware, interacting with the Instrument Control System (ICS), and saving science data. Because of these similarities, the ATST Software Group has developed the Standard Instrument Framework (SIF), a set of software components comprising a framework that can be used to implement instrument controllers with common functionality for all ATST instrumentation. The SIF is built upon the ATST Common Services Framework (CSF) and includes controllers capable of interfacing with the ICS, managing sub-controllers and multiple camera systems, as well as coordinating the instrument’s mechanical mechanisms and other hardware. The key to this framework is the principle that each controller has a small, well defined task and when the individual pieces are combined, a powerful control system may easily be implemented. Moreover, because most of the instruments for the ATST are being developed by partner institutions, the SIF allows for standardization of the instrument control systems throughout the instrument suite and reduced software development effort for the partners. This will lead to significant code reuse and a smaller code base that is easier to maintain.