1. MATLAB Feedback Phase II Commissioning D. Fairley & J. Wu

2. Topics • New Block Diagram • Demo • New Requirements • Tradeoffs and other Issues • Questions / suggestions D. Fairley & J. Wu

3. D. Fairley & J. Wu

4. DEMO D. Fairley & J. Wu

5. New Requirements • Additional Feedbacks • 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? D. Fairley & J. Wu

6. 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? D. Fairley & J. Wu

7. 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 D. Fairley & J. Wu

8. LCLS – Accelerator and Bunch Compressor Schematic D. Fairley & J. Wu

9. Example: 6 by 6  5 by 5 L3 Phase L3 Phase D. Fairley & J. Wu

10. 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 D. Fairley & J. Wu

11. The End • Questions? • Suggestions? D. Fairley & J. Wu