Reports until 11:11, Monday 24 April 2023
H1 GRD
gabriele.vajente@LIGO.ORG - posted 11:11, Monday 24 April 2023 - last comment - 08:48, Tuesday 25 April 2023(68948)
New THERMALIZATION guardian ready for operation

Wrote a new guardian called THERMALIZATION. FOr now it will only change the PRCL gain following a tyrend close to what we measured over past locks.

The plan is that ISC_LOCK will request the "THERMALIZED" state after LOWNOISE_LENGTH_CONTROL, instead of turning on the PRCL UGF servo.

The THERMNALIZATION guardian will transition to "SERVO_PRCL_GAIN" and start increasing the PRCL gain (with 30s ramp) following the equation:

H1:LSC-PRCL1_GAIN = [Gain set in LOWNOISE_LENGTH_CONTROL] * SCALE
SCALE = 1 + 3*(1 - exp(- time / 7800))

After 6 hours the THERMALIZATION guardian will stop adjusting the gain and go to "THERMALIZED"

We still need to test this new guardian at the next lock acquisition

Comments related to this report
gabriele.vajente@LIGO.ORG - 08:48, Tuesday 25 April 2023 (68979)

The new hard-coded adjustment of the PRCL gain worked almost correctly. During one lock the initial gain was incorrectly set to 8 instead of 6. This probably happenend becvause the THERMALIZATION guardian read the PRCL1 gain too early after ISC_LOCK changed from 8 to 6.

I added a 10 seconds wait in the main() function of the SERVO_PRCL_GAIN to avoid this problem in the future.

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