Maunakea Operations and Engineering Workshop Domes & Shutters Keck 2 Dome Control PLC Upgrade Andrew Cooper W. M. keck Observatory Maunakea Operations and Engineering Workshop, 8 December 2016

No Manufacturer Support Programming software DOS based An Obsolete PLC As of 2014 the Keck 2 dome and shutters were controlled by an Allen Bradley PLC2 30 year old technology No Manufacturer Support Programming software DOS based Battery backed RAM (no Flash) Maunakea Operations and Engineering Workshop, 8 December 2016

An Obsolete PLC Maunakea Operations and Engineering Workshop, 8 December 2016

FY2016 Upgrade Project to a modern and supportable PLC Upgrade Path FY2016 Upgrade Project to a modern and supportable PLC Original Plan was an upgrade to a PLC5 Allen Bradley ControlLogix PLC? Plan must allow for continuous operation, no shut down for transition. Maunakea Operations and Engineering Workshop, 8 December 2016

Decision to transition to an AB ControlLogix Testing! Decision to transition to an AB ControlLogix Existing PLC chassis would be converted to a remote I/O arrangement maintaining all existing field wiring The PLC code was ported by hand with a few modifications Extensive testing with a full simulator Installed and tested in dome June 2015 Switched in as the operational system July 2015 Maunakea Operations and Engineering Workshop, 8 December 2016

Testing! Maunakea Operations and Engineering Workshop, 8 December 2016

Result Maunakea Operations and Engineering Workshop, 8 December 2016

Take-away It was possible to layer the modern controller atop the old hardware for a relatively painless upgrade path. There is now a clear path forward to phasing out the remainder of the older hardware on an as needed basis Maunakea Operations and Engineering Workshop, 8 December 2016