Control and systems software for the Cosmology Large Angular Scale Surveyor (CLASS)

The Cosmology Large Angular Scale Surveyor (CLASS) is an array of polarization-sensitive millimeter wave telescopes that observes ∼ 70% of the sky at frequency bands centered near 40 GHz, 90 GHz, 150 GHz, and 220 GHz from the Atacama desert of northern Chile. Here, we describe the architecture of the software used to control the telescopes, acquire data from the various instruments, schedule observations, monitor the status of the instruments and observations, create archival data packages, and transfer data packages to North America for analysis. The computer and network architecture of the CLASS observing site is also briefly discussed. This software and architecture has been in use since 2016, operating the telescopes day and night throughout the year, and has proven successful in fulfilling its design goals.