Phase II Commissioning MATLAB Feedback Phase II Commissioning Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

Questions / suggestions Topics New Block Diagram Demo New Requirements Tradeoffs and other Issues Questions / suggestions Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

DEMO Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

New Requirements Additional Feedbacks Creating new feedback loops Bunch Charge Longitudinal will expand to include BC2 Energy and BC2 Bunch Length No DL2 energy for now, see SLC BPMs below L2 and L3 Launch Creating new feedback loops Who is the target user? User needs to be familiar with EPICS databases I suggest a team; physicist+controls sw Reading SLC BPMs Longer response time Throwaway code We have 3 EPICS BPMs for longitudinal; allows 5x5 fully EPICS Controlling SLC Magnets There was discussion about leaving the correctors under SLC control, what are the tradeoffs there and is this a real option? Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

New Requirements Automatically switch configurations MATLAB script must read these conditions from PVs and make decision on each iteration of the algorithm, since it cannot be ‘interrupted’; a cost in processing time not ‘standard’ across feedbacks. May not be an issue now, but specialization means maintenance difficulties, and implementation difficulties looking ahead to fast-feedback Runtime adjustment of gains, weighting factors, mask matrix MATLAB script must read and apply these parameters from PVs at each iteration of the algorithm, whether they’ve changed or not. Also not ’standard’, see above. Cascading Feedbacks Longitudinal already satisfies this Is cascading required for transverse? Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

Mask Matrix  Switching mode Introduce a Mask Matrix MM The user can design a specific feedback, may be needed in commissioning stage The Mask Matrix can be multiplied on the Gain Matrix MG Minimum modification to existing longitudinal algorithm Performs unnecessary calculation to get the correction on the actuator Yet, the correction is not applied (ie. Becomes 0 change) The Mask Matrix can be “multiplied” on getting the measurement, so to stop the measurement and to stop unnecessary calculation Yet, the framework stays the same Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

LCLS – Accelerator and Bunch Compressor Schematic Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

Example: 6 by 6  5 by 5 L3 Phase L3 Phase Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

Cascade Loops: Injector, L2, and L3 Launch Identify transport matrices from loop i (=1 … n) to loop j (=i+1 … n) Based on Model? How accurate is the model, if the n—loop and n+1—loop are separated too far physically? We can measure the transport matrices Injector launch is commissioned and worked well For each stage n, similar implementation as that for injector launch However, the measurement should subtract what comes from the upstream loop disturbance If n is too large, this becomes cumbersome Minimum modification, and the framework stays the same Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu

The End Questions? Suggestions? Oct. 11, 2007 LCLS Physics Meeting D. Fairley & J. Wu