kiwamu.izumi@LIGO.ORG - posted 16:54, Tuesday 16 February 2016 - last comment - 20:35, Wednesday 17 February 2016(25575)
ESD bias voltage sign-flipped on ETMX and ETMY
Jeff, Darkhand, Kiwamu,
We have been meaning to do this, but kept missing a chance to do. Today we have fliiped the sign of the ESD bias voltage both on ETMX and ETMY.
This alog only describes what we did on the digital front end models. We will perform a set of confirmation measurement and verify the H1 DARM model later.
See alog 22135 for a concise summary of the bias flip.
[Bias flip on ETMY ]
- We flipped the bias request voltage from +9.5 => -9.5 in SUS-ETMY_L3_LOCK_INBIAS
- No other change required in SUS-ETMY because there is a if statement in ISC_LOCK which automatically checks the change in the bias sign and compensate for it by changing the sign of L3_DRIVEALIGN_L2L_GAIN.
- In CAL-CS, we have changed DARM_FE_ETMY_L3_DRIVEALIGN_L2L_GAIN from +30 to -30.
- Similarly, we have changed DARM_ANALOG_ETMY_L3_GAIN from -1 to + 1.
[Bias flip on ETMX]
- We flipped the bias request voltage from -9.5 to +9.5.
-
We flipped DRIVEALIGN ellements as follows.
- SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN, from +1 to -1
- SUS-ETMX_L3_DRIVEALIGN_L2P_GAIN from +0.021 to -0.021
- SUS-ETMX_L3_DRIVEALIGN_L2Y_GAIN from 0.007 to - 0.007
- We changed the force coefficient of the linearization from -124518.4 to + 124518.4 in SUS-ETMX_L3_ESDOUTF_LIN_FORCE_COEFF
- All the the above changes are now written in ISC_LOCK with a if statement, so that it automatically checks the bias sign and apply a proper set of parameters.
- We have not updated CAL-CS for ETMX because it is currently not in use.
We took open loop and Pcal sweep measurements in nominal low noise after the biases were flipped. They reside at:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PostO1/H1/Measurements/DARMOLGTFs/2016-02-16_H1_DARM_OLGTF_7to1200Hz.xml/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PostO1/H1/Measurements/PCAL/2016-02-16_PCALY2DARMTF_7to1200Hz.xmlDarkhan will process the data later.
P.S.
I have updated the SDF accordingly for SUS-ETMX and ETMY and CAL-CS when the interferometer was in nominal low noise.
Kiwamu, Darkhan,
Summary
Our analysis of a DARM OLG TF and a PCALY to DARM TF measurements taken after the ESD bias sign flip on Feb 16, 2016 showed that:
Disscussion (actuation function)
The ETM ESD drivers' electronics and front-end FOTON filters associated with the ESD responses were recently updated, see LHO alogs 25468, 25485. Since the front end filter's do not perfectly cancel the ESD response, in the Matlab parameter files we used a better approximated ZPK responses that are based on the old ESD electronics measurements. Since currently we do not have TF measurements for the new ESD driver electronics, we have removed all of the compensations (for the non-perfect front-end filters) from the Matlab analysis of the DARM and PCALY to DARM TF measurements.
Measurement files, scripts
DARM OLG TF and PCALY to DARM TF measurements have been committed to CalSVN:
Runs/PostO1/H1/Measurements/DARMOLGTFs/2016-02-16_H1_DARM_OLGTF_*.txtRuns/PostO1/H1/Measurements/PCAL/2016-02-16_PCALY2DARMTF_*.txt
Up to date filter files have been copied to
Common/H1CalFilterArchive/h1omc/H1OMC_1125881488.txtCommon/H1CalFilterArchive/h1susetmy/H1SUSETMY_1126240802.txt
DARM parameter file and comparison script have been committed to
Runs/PostO1/H1/Scripts/DARMOLGTFs/CompareDARMOLGTFs_O1andPostO1.mRuns/PostO1/H1/Scripts/DARMOLGTFs/H1DARMparams_1139722878.m
Results (plots) are in
Runs/PostO1/H1/Results/DARMOLGTFs/2016-02-16_*.pdf