1. Rack Control Paul Maley DRAFT 1 September 2003

2. Overview –Status of monitoring & safety system –Big System Baseline – reminder Alternative –Summary

3. Status –Documentation Very late – my apologies Specification & Implementation – draft available Identical functionality as in previous discussions –Prototype monitoring board in test Soon will be on display – “en marche” –Auxiliary PCB shielding tests in progress –Smoke detector tender out

4. Big System / Little System –Little system: Monitoring & safety Physically located within the rack Totality of ESS’s contribution to date –Big system: Interaction of little system with everything else Baseline solution was discussed and seemed reasonable (Nov 2002) Hard to accept little system without knowing big system more clearly?

5. Baseline

6. Smoke Detection System

7. RM & safety Interface T-switch Monitoring DCS Smoke -in rack -one per rack -far from rack (PLC) -one per rack/rack group

8. Little system – inadequacies? –As is, multiple safety devices possible but cannot distinguish different faults directly Never found a solution Thus did not form part of baseline –Other safety devices required? Do not cut the rack when really it is something in the rack you wish to cut! Systems (e.g. cooling water) should be monitored and actions taken at a higher level

9. Little system – inadequacies –Thermo-switch and smoke detector asymmetric Thermo-switch cuts at rack level Smoke detector cuts at higher level –Various “daisy-chaining” scenarios

10. Cutting power - baseline Control from DSS or fire detection PLC Rack Control directly from Thermo-switches

11. Alternatives –“DSS clone” Programmable control Symmetric solution fine-grain information available Hardware existing –Extended “Fire detection control board” Have the PLC for the smoke detectors Connect thermo-switches directly

12. Extended “Smoke PLC” ST Smoke detector Control system STST Additional modules Hardwired output for control DCS - diagnostics

13. Summary –Monitoring & safety system As proposed it satisfies baseline (Inelegant wrt cutting power at different levels) (Not as flexible as I (you?) would like) –Alternative solution Attractive?