On monday night, we were able to measure the top mass to test mass L2L transfer functions on ETMy and ETMx, using the ALS-{X/Y}_REFL_CTRL signal for the response. The idea is to measure and invert the plant for each of the following stages (TOP UIM and TST).

We did the measurement in two configurations :

1- oplev damping feedback to UIM on
2- oplev damping feedback to UIM off

In both cases, the slow feedback was ON (using the inverted fit from the model) and the length to pitch and length to yaw decoupling filters were engaged (gain of -1).

The L2L measured plant is sligthly different when oplev is on/off. With oplev on, the Q of the first QUAD resonnance is higher.

The data was fitted for the 4 measurements (using the script fit_topLong2tstLong.m under QUAD/Common/FilterDesign/Scripts), and the inverted plant was installed in the LOCK filter banks FM1 (tuned for oplev damping on : "invL2L") and FM2 (tuned for oplev damping off "invL2L2"). The fitting is summarized in the attached plots.

The phase of EX measurement is off by 180 degrees for some reason.

The results were saved under
EY
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data
2014-04-28_H1SUSETMY_M0_L2LPY_OL_OFF_SweptSine.xml
2014-04-28_H1SUSETMY_M0_L2LPY_SweptSine.xml

EX
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data
2014-04-28_H1SUSETMY_M0_L2LPY_OL_OFF_SweptSine.xml
2014-04-28_H1SUSETMY_M0_L2LPY_SweptSine.xml