1. Low Level RF Status Outline LLRF controls system overview
LLRF controls software status for
Phase and Amplitude Detector (PAD)
VME local feedback and timing trigger source
Phase and Amplitude Controller (PAC)
Host applications
LLRF controls software testing status
LLRF documentation and review status
See SC1/SC2 Accelerator Systems LLRF Status and Design presentation for safety, hardware status, system requirements, cable routing and commissioning test plan

3. Status of Software for Injector Turn-on
PAD Software
Operational
PAC Software
Local Feedback (in VME)
Data analysis shows simple feedback algorithm will work.
Optimization of algorithm continues.
Time measurement: measure time needed for data acq, for transfer to VME, for VME processing, for transfer to PAC.
Time measurement: needed for multiple local loops. Eg. Measure scalability from 1 to N instances.
This IOC needs to be SLC-aware
This IOC uses EVR and needs to set up trigger delays in response to timing events
RF Gun Temperature Feedback
In Design
Calibration and Test
Host Applications
In process of specifying
Storing of boot params, serial numbers, etc in flash or on the board for PAD and PAC

4. PAD Software Different LLRF apps need different calculations
There are 5 different algorithms:
AVG+STD – calculate average I and Q and variance of I and Q
RF WF – calculate average I and Q
WF – calculate average of sample
RF WF2 – calculate average I and Q of two samples
IQ Cal – send 64K raw data waveform
Each channel on a PAD can run a different algorithm with its own sample size and offset
Each PAD can run in CALIBRATION or RUNNING mode, which use different algorithms

5. PAD GUI here

6. PAC Software
PACs can run in either CALIBRATING or RUNNING mode. A state machine keeps track.
If CALIBRATING, calibration waveforms are loaded into FPGA and I and Q gains and offsets can be adjusted.
If RUNNING, I and Q gains and offsets are fixed, operational waveforms are loaded into FPGA and I and Q adjustments can be applied at the operational frequency.

7. PAC GUI here

8. VME Software Generic Feedback algorithm:
Phase and amplitude are calculated from I and Q averages from each channel of the PAD
Phases are corrected by phase offset correction
Amplitudes are corrected by amplitude power correction
Phase and amplitudes are weighted by configurable weighting factors to determine one average phase and amplitude
Pavg=(P0*PWT0 + P1*PWT1 + P2*PWT2 + P3*PWT3)/4*(ΣPWTi)
Aavg=(A0*AWT0 + A1*AWT1 + A2*AWT2 + A3*AWT3)/4*(ΣAWTi)
Local or global feedback corrections are applied (0 < A <= 1)
Pcor = A(Pdes – Pact) + (1-A)Pcorn-1
Pcorn+1 = A(Pdes n+1 – Pactn+1) + (1-A)Pcorn
For amplitude, (Pdes – Pact) is replaced by Pdes/Pact
Corrected phase and amplitude is converted to I and Q
Corrected I and Q values are sent to PAC

9. Local feedback

10. VME Software Beam Phasing Cavity algorithm (for Laser Timing):
Two sets of I and Q averages arrive (since there are two windows of interest)
Phase1 is calculated from I1 and Q1
Phase2 is calculated from I2 and Q2
Measured beam phase is the y-intercept of the equation to the line of phase as a function of FIFO position
Frequency is the slope of the line
Amplitude is calculated from I1 and Q1 (only)
Phase is corrected by phase offset correction
Amplitude is corrected by amplitude power correction
Local feedback corrections are applied
Corrected phase and amplitude is converted to I and Q
Corrected I and Q values are sent to laser PAC

11. Beam Phase Cavity: calculation of freqency and phase from a line through 2 points

12. VME Software Other calculations For RF Reference Distribution
Phase and amplitude are calculated from I and Q averages from each channel of the PAD
Phases are corrected by phase offset correction
Amplitudes are corrected by amplitude power correction
Standard deviation of I and Q is calculated from I and Q variances from each channel of the PAD

13. VME GUI here

14. Host Applications Generic Distribution System PAC PAD Testing
Correlation plots
Calibration of power levels using beam energy
Distribution System
Rotate Phase 360 degrees
Monitor Phase Errors in Dividers
Correct Divider Phase Errors
PAC
Calibration Mode Operation
Generate and Load Waveforms
Panels for Phase and Amplitude Adjustment
PAD Testing
Crosstalk, SNR, Noise Floor
Sine Wave Histogram
Panels for Phase and Amplitude Monitoring
Local Feedback Control Panels

15. Status of Documentation + Reviews
All documentation and reviews are accessible from LLRFhomepage
Recent milestones:
LLRF Control Design Specification
This Engineering Specification Document was signed off by Project Office on 9/27/2006.
LLRF Final Design Review
This review was held on 9/19/2006.
The scope of the review covered:
RF Distribution Reference System for Injector Commissioning
RF System for Injector Commissioning
PAD
PAC
VME
These were the goals given to the committee last September:
Injector RF turn on is January 3, The designs of the prototype PADs and PACs have been built and tested. Fabrication is scheduled for October, Please review analysis of test data and the proposed design and comment on the proposed systems' ability to meet LCLS specifications.
Review our test plans and suggest improvements

16. Lab Test Setup Reference, PAC, PAD
The LCLS RF system duplicated in the lab and used for testing of PADs and PACs.
At least two of each frequency generation chassis is built to measure phase noise levels.
Most components will have development chassis which can be used as a spare.

17. LCLS New Reference System Lab Measurements
Lab Tests Show Reference System Noise Levels Meet All LCLS Requirements
2856MHz = 70fSrms
2830.5MHz = 70fSrms
25.5MHz = 2pSrms
102MHz = 2pSrms
2856MHz : 22fSrms 10Hz to 10MHz
2830.5MHz : 22fSrms 10Hz to 10MHz
John Byrd - LBNL
25.5MHz : 152fSrms 10Hz to 1MHz
102MHz : 281fSrms 10Hz to 10MHz

18. SLAC Linac RF – New Control
The new control system will tie in to the IPA Chassis with 800W of drive power available. The RF Reference will be from the new RF reference system.
Solid State Sub-Booster PAC
I and Q will be controlled by the PAC chassis, running 16bit DACs at 102MHz. Waveforms to the DACs will be set in an FPGA through a microcontroller running EPICS on RTEMS.
Existing System

19. Linac Station 21-1 Tests (Aug.18, 2006)

20. Linac 21-1 Test Set-up
Power Coupled out from 476MHz MDL drives a 476MHz Amplifier which feeds a 6X Multiplier from 476MHz to 2856MHz.
The 2856MHz out drives both the LO generator and the PAC.
The MHz LO and 102MHz CLK Generator supplies the LO and CLK to the PAD. A CLK output of the PAD drives the PAC CLK.
The PAC output drives the SSSB.
The SSSB drives the existing IPA chassis
The klystron output coupler is used to measure phase and amplitude with the new PAD.

21. Linac 21-1 Test Results
Tests were done in the gallery with no temperature regulation on cables. Average RMS value of 2 second sliding average is degrees.
Exponential Smoothing Yields the Following Results. Lowest noise is with a time constant of about 2 points.