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Reports until 17:59, Thursday 05 June 2025
H1 AOS (ISC)
bin.wu@LIGO.ORG - posted 17:59, Thursday 05 June 2025 - last comment - 15:03, Friday 06 June 2025(84842)
ASC Camera offset adjustments & new states

Bin Wu, Julia Rice

We have been working on writing a new Guardian script that will allow us to switch off the dither loops sooner in the power up process and instead use cameras.

We first looked at the error signals in the ASC cameras to see if we could adjust offsets to better values. We did this for the CAMERA_SERVO guardian, and added new intermediate states, including TURN_ON_CAMERA_25W_OFFSETS and TURN_ON_CAMERA_MOVESPOTS_FIXED_OFFSETS. We've attached screenshots showing the graph before and after our additional states. Below are the values we used for offsets for each. The weight from DITHER_ON to TURN_ON_CAMERA_25W_OFFSETS is set to be 10.

TURN_ON_CAMERA_25W_OFFSETS

PIT1 -233
PIT2 -168
PIT3 -217
YAW1 -248
YAW2 -397
YAW3 -338

TURN_ON_CAMERA_MOVESPOTS_FIXED_OFFSETS

PIT1 -232
PIT2 -159
PIT3 -226
YAW1 -248
YAW2 -431
YAW3 -351

We also adjusted the offsets for TURN_ON_CAMER_FIXED_OFFSETS:

PIT1 --230
PIT2 -181
PIT3 -226
YAW1 -245
YAW2 -418
YAW3 -353

These are added in lscparams.py. We also added the necessary code into CAMERA_SERVO.py.

We also added a parameter in lscparams.py for new ADS camera CLK_GAIN at 25W  ('ads_camera_gains_25W', screenshot included)

Right now the new states are not requestable, so they will need to be ran manually to test. We haven't made any change to the ICS_LOCK guardian.

Images attached to this report
Comments related to this report
julia.rice@LIGO.ORG - 11:58, Friday 06 June 2025 (84860)

Also added lines in CAMERA_SERVO.py under DITHER_ON to check if ISC_LOCK is at 25W when proceeding through self counter loop, see attached.

Images attached to this comment
julia.rice@LIGO.ORG - 15:03, Friday 06 June 2025 (84872)

Adding A2L gains for reference, first chart clarifies dither loop actuators and cameras.

Beam pointing actuator ADS Dither Cam Sensor
PRM PIT Dither ITMX: ITMX P2L BS Cam 1 PIT
PRM YAW Dither ITMX: ITMX Y2L BS Cam 1 YAW
X SOFT PIT Dither ETMX: ETMX P2L ETMX Cam 2 PIT
X SOFT YAW Dither ETMX: ETMX Y2L ETMX Cam 2 Yaw
Y SOFT PIT Dither ETMY: EMTY P2L ETMY Cam 3 PIT
Y SOFT YAW Dither ETMY: ETMY Y2L ETMY Cam 3 Yaw

 

GRD State A2L Gain Cam Offset
POWER_25W [506] P2L ITMX: -1.25 -233
  P2L ETMX: 0.85 -168
  P2L ETMY: 0.85 -217
  Y2L ITMX: 0 -248
  Y2L ETMX: 0 -397
  Y2L ETMY: 0 -338

 

GRD State A2L Gain Cam Offset
MOVE_SPOTS [508] P2L ITMX: -1.8+1.0 -232
  P2L ETMX: 4.0 -159
  P2L ETMY: 3.6+1.0 -226
  Y2L ITMX: 2.1 -248
  Y2L ETMX: 4.4 -431
  Y2L ETMY: 2.2+1.0 -351

 

GRD State A2L Gain Cam Offset
MAX_POWER [520] P2L ITMX: -0.54 -230
  P2L ETMX: 3.31 -181
  P2L ETMY: 5.57 -226
  Y2L ITMX: 3.23 -245
  Y2L ETMX: 4.96 -418
  Y2L ETMY: 1.37 -353
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