1. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Vacuum Controls System Concept Review and Preliminary Design Review Stephen Schuh 16 November 2005

2. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Outline System Concept Review and Preliminary Design Review Requirements Personnel Engineering Requirements Block Diagram Interfaces Alternatives Test Plan Software Quality Control & Reliability Safety

3. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Requirements Use existing controls for linac vacuum hardware where possible Fast and slow valves Vacuum gauges Vacuum pumps Waveguide vacuum protection for linac klystrons Remote control and status in EPICS for all new gauges, pumps, and valves. Gauge and pump readings in graphical and numerical form Valve status and control Infrastructure for archiving data and correlating data with other control system data Local control and status for all new gauges, pumps, and valves, when possible COTS gauge and pump controllers SLAC-built valve interface with open/close buttons, interlock status in support buildings SLAC-built valve interface (“J-Box”) in tunnel Key interlocks where possible

4. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 More Requirements Automatically close gate valves to isolate beam line regions where vacuum pressure exceeds the allowed upper limit Measure pressure with vacuum gauges and/or vacuum pumps Interlocks: associate each valve with gauges and/or pumps Configure interlock logic with software Ability to bypass a faulty gauge or pump from EPICS Notify MPS when a gate valve is closing or closed Shut off injector klystron modulators (the gun, L0-A, and L0-B) when waveguide vacuum pressure exceeds the allowed upper limit 3 beam pulse delay at 120 Hz acceptable (25 msec) Existing controls protect remaining linac klystrons Close all valves in a PPS region if that region is set to controlled or permitted access

5. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Personnel Customers: SLAC Vacuum Group (MFD) SLAC Controls Department (CPE) Physicists and Operators First Need: Injector Commissioning – Nov 2, 2006 Team: Stephen Schuh – Software Tom Porter – Hardware

6. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Engineering Requirements Response time of gauges: 15 msec is acceptable Interlock logic: ~3 msec is acceptable Communication with MPS: Notify MPS that valve is closing or closed Goal: shut off beam before it strikes a vacuum valve MPS responds within 8 msec Valve takes hundreds of msec to close

7. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Block Diagram

8. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Interfaces Control System: IOC needs Ethernet and serial (RS-232) PLC needs Ethernet; might also need private Ethernet to talk to other PLC crates Other Subsystems: Valve status to MPS: Shut off beam when valve is closed or closing. Waveguide vacuum status to modulator: Shut off modulator when WG vacuum is bad Access state from PPS: Close valves when in controlled or permitted access. T-Cav waveguide valve status to PPS: Keep people out of injector vault if valve is open Vacuum Components: Valve: VAT Series 48 Direct signals: air solenoid, open and closed limit switches, air pressure switch Gauge Controller: MKS 317, Helix 370 Direct signals: gauge HV permissive, pressure, set point relays Communication: RS-232 Pump Controller: Gamma Digitel MPC Direct signals: pump HV permissive, pressure, set point relays Communication: RS-232

9. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Alternatives Valve control Use SLAC Programmable Multi Valve Controller instead of Allen-Bradley PLC Omit valve control interface Omit J-Box Ion Pump Power Supply Use Kaiser instead of Gamma Ion pump cable: Gamma SafeConn vs SLAC coax Gauges 15 msec gauge response vs ~100 msec gauge response

10. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Test Plan Build prototype Hardware: IOC, PLC, valve, valve control chassis, J-Box, pump, four gauges Software: PLC code, EPICS software Location: MFD shop (they’re already testing gauges) Schedule: Most parts for prototype should arrive by Jan 1 Just starting work on IOC Test each component either before installation or in place

11. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Software PLC code for valve logic (help from LLNL) EPICS database and screens EPICS device support Allen-Bradley ControlLogix PLC MKS 937a Gauge Controller Helix/Granville-Philips 370 Gauge Controller Gamma Digitel MPC Ion Pump Power Supply

12. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Quality Control and Reliability System design similar to SNS PLC’s are widely used: vacuum, MPS, RF control, PPS Most components are already in use at SLAC Gauges and gauge controllers Allen-Bradley PLC J-Box for valve control Hardware new to SLAC Gamma ion pump power supply - Tom Porter’s tests

13. Stephen Schuh Vacuum Controls SCR and PDRschuhs@slac.stanford.edu 16 November 2005 Safety Vacuum Safety Review – September 2005 Slides and report: https://www-lcls-internal.slac.stanford.edu/slaconly/Injector-Linac-Meeting-Minutes/Injector-Linac-Vacuum/LCLSVacuumSafetyReview/ Ion Pump HV Cable – 6 kV, 100 mA Gamma SafeConn vs SLAC coax SafeConn has an extra interlock wire – turn off HV when cable is unplugged This interlock gets no credit from SLAC electrical safety Mixed high voltage and low voltage cable Plan: Use SLAC cable instead of SafeConn cable