Sheila, Matt, Mayank, Camilla
Today we changed the nominal FC beamspot control:
- Old: Using the TRANS A PD feeding back to INJANG and ZM3
- New: ADS PIT2/YAW2 oscillators into FC2 (Maynak set up in 8309) into INJ_ANG and feeding back on ZM3.
- ASC oscillators on FC1 and FC2 have been left on so that we can check if we also need to use FC1 signals feeding back to ZM1 as LLO does.
Sheila put the OSC amplitudes back to 10 and steps each AL2 gain to check its in I only (need to change PIT2 by 90deg), then adjusted A2Ls to get I close to zero. YAW1 has more noise than others.
Turned off the INJ_ANG ASC (feeds back to ZM3 as "FC beamspot control") and then steps ZM2/3/ P/Y offsets. After we worked out the matrix element, we tried to close each loop: turned off input, clear history, turn back on input, turn on gain. Closed each one and and did the next. Closed INJ_ANG for ZM3 in PIT and YAW.
ZM2 had a large response in PIT2 and not a noticeable response in PIT1. If we move ZM1, we see it in both PIT1 and PIT2, but the INJ_ANG loop zeros PIT2 but the PIT1 error signal remains. There's too options to avoid this, either do a combination of ZM1/3 to avoid cross coupling, but the easier option is to keep the INJ_POS loop slower (gain lower) than INJ_ANG. The change was very small (or no change) for YAW1 so we decided to only use PIT1/2 to INJ_ANG to ZM3 P/Y as the feedback for this week.
| Optical ALIGN | INJ ANG | ASC_ADS | Matrix Element Needed | |
| ZM3 P | +3 on ZM3 P | -0.00480 in P | +5.978 on PIT2 | -0.0008 (much too small, increased to -0.08) |
| ZM3 Y | -7 on ZM3 | +0.0095 in Y | -4.6 on YAW2 | -0.002 (wrong sign, too small, changed to +0.06) |
Edited SQZ_FC guardian OFFLOAD_FC_ASC to also offload INJ_POS if we decide to use these filters. As the intergrators as still in the FC ASC filters, this is a homemade ASC offload, rather than the standardized ISC one. A future task is to move the intergrators into the ZM suspensions as we did for ZM4/5/6.
Accepted sdfs, and checked the that FC Guarudan just switches on the SQZ-FC_ASC_INJ_ANG_P/Y inputs and doesn't touch the matrix elements. INIT did reset the outmarix, but this should be controlled only by sdf so I deleted that block and reloaded.
We did split up the filters for the filter cavity ASC, adding intergrators with a zero at 0.01 Hz to FC1,2 and ZM3 ASC filter banks (M1_LOCK_P and Y), and modifying the true intergators in the ASC filters to have poles at 0.01 Hz. Then we modified the guardian so that it uses the standard generic offloading guardian state (gen_OFFLOAD_ALIGNMENT_MANY). We also removed the state called clear_FC_ASC from the graph, because that shouldn't be needed if we are using the standard offloading guardian.
