1. 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

2. 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

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

4. 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

5. 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

6. Testing!
Maunakea Operations and Engineering Workshop, 8 December 2016

7. Result
Maunakea Operations and Engineering Workshop, 8 December 2016

8. 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