Distributed state machine supervision for long-baseline gravitational-wave detectors
The Laser Interferometer Gravitational-wave Observatory (LIGO) consists of two identical yet independent, widely separated, long-baseline gravitational-wave detectors. Each Advanced LIGO detector consists of complex optical-mechanical systems isolated from the ground by multiple layers of active seismic isolation, all controlled by hundreds of fast, digital, feedback control systems. This article describes a novel state machine-based automation platform developed to handle the automation and supervisory control challenges of these detectors. The platform, called Guardian, consists of distributed, independent, state machine automaton nodes organized hierarchically for full detector control. User code is written in standard Python and the platform is designed to facilitate the fast-paced development process associated with commissioning the complicated Advanced LIGO instruments. While developed specifically for the Advanced LIGO detectors, Guardian is a generic state machine automation platform that is useful for experimental control at all levels, from simple table-top setups to large-scale multi-million dollar facilities.
© 2016 AIP Publishing. Received 6 April 2016; accepted 14 August 2016; published online 6 September 2016. The author would like to thank the following people: Daniel Sigg for many fruitful discussions on the theory and practice of automation in general and automation of gravitational wave detectors in particular, Matthew Evans and Sam Waldman for their initial seed of an idea and subsequent sprout of work, Charles Celerier for his invaluable help in early development and testing, and Robert Ward for breaking the ice and getting the commissioners using this new system. In addition, the author thanks the entire Advanced LIGO commissioning team who put up with the initial growing pains, helped push the system to its full potential, and wrote most of the user code that actually controls these incredible instruments. LIGO was constructed by the California Institute of Technology and Massachusetts Institute of Technology with funding from the National Science Foundation and operates under Grant No. PHY-0757058. Advanced LIGO was built under Award No. PHY-0823459.
Published - 1.4961665.pdf
Submitted - 1604.01456v2.pdf