craig.cahillane@LIGO.ORG - posted 20:08, Friday 11 February 2022 - last comment - 15:33, Monday 14 February 2022(61721)
Measured ISS second loop OLG
First measurement of ISS second loop olg since PSL reinstall. UGF is 1 kHz. Phase margin is 45 degs. Notes: - only engaged Boost 1 for the measurement, Boost 2 seemed to make the diffracted power much more noisy. - ISS VGA gain is was 0 dB - readbacks for PDs are wrong Data from measurement stored in https://git.ligo.org/aligo_commissioning/psl_measurements Made a template for this measurement in this directory atcode/iss_second_loop_olg_SR785_template.ymlTo use it, activate thepslconda env and runpython SRmeasure.py iss_second_loop_olg_SR785_template.yml
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Craig, Austin, Elenna
Tried to turn on the second boost, failed to get a stable loop with this boost engaged.
We managed to get performance similar to what Keita measured in 2021 (alog 58850) by cranking the H1:PSL-ISS_SECONDLOOP_GAIN from 0 to 30 dB.
UGF = 25.6 kHz
phase margin = 30 degs
Measurement in
https://git.ligo.org/aligo_commissioning/psl_measurements
at
data/iss_second_loop_olg/iss_second_loop_olg_30_dB_second_loop_gain_slider_14-02-2022_125404.txt
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