Reports until 11:12, Thursday 07 March 2013
H1 SUS
jeffrey.kissel@LIGO.ORG - posted 11:12, Thursday 07 March 2013 (5701)
Updated Damping Filters on HAM2 and HAM3 SUS
P. Fritschel had designed better performance damping filters for the longitudinal degree of freedom for the HSTSs (see LLO aLOG 4739), which have been installed for quite some time at LLO. Further, though the performance isn't necessarily better, the gains for all other degrees of freedom have been tuned to give reasonable Qs, with a consistent set of filters between degrees of freedom (see LLO aLOG 4061). Finally, using these filters, I've reproduced their design in matlab, set them as default filters to be wrapped around the production model, and am able to reproduce closed-loop transfer functions to very good accuracy (see LLO aLOG 6041).

In order to take advantage of these changes (better longitudinal performance, site-to-site symmetry, and having a accurate model of the filters in the can), I've copied over the filters and gains from LLO. 

All of the above refers to the HSTSs. For PR3, an HLTS, its performance has yet to be tested, but I've got a similar successful model of the LLO filters and gains. So, again, in the interest of not having many different configurations of loops scattered about, I've also copied LLO's HLTS filters and gains.

So you don't have to go scouring, I'll reproduce the settings here:

HSTSs:
L: FM3 [resg], FM5 [normL], G = -1.0
T: FM1 [0:30,30], FM5 [normT], FM10 [ellip50], G = -2.0
V: FM1 [0:30,30], FM5 [normV], FM10 [ellip50], G = -3.0
R: FM1 [0:30,30], FM5 [normR], FM10 [ellip50], G = -0.2
P: FM1 [0:30,30], FM5 [normP], FM10 [ellip50], G = -2.0
Y: FM1 [0:30,30], FM5 [normY], FM10 [ellip50], G = -1.0

HLTSs;
L: FM1 [0:15,15], FM5 [normL], FM10 [ellip50], G = -2.0
T: FM1 [0:15,15], FM5 [normL], FM10 [ellip50], G = -5.0
V: FM1 [0:15,15], FM5 [normL], FM10 [ellip50], G = -1.0
R: FM1 [0:15,15], FM5 [normL], FM10 [ellip50], G = -0.02
P: FM1 [0:15,15], FM5 [normL], FM10 [ellip50], G = -0.002
Y: FM1 [0:15,15], FM5 [normL], FM10 [ellip50], G = -0.02

Note, the repeat of normL for every degree of freedom in the HLTS is *not* a typo. The purpose of the norm filter is to compensate for the calibration of the OSEMs, and in the case of the HSTSs, to absorb some of the gain of the filter such that the visible GAIN field is of order unity. The calibration is turned on for both types of SUS, so that inversion is in place -- (1/to_um) = 43.478, but we've not yet tuned and absorbed the gains for the HLTSs, so the value is the same for each degree of freedom for that SUS type.

All six filter files for H1SUSMC1, H1SUSMC2, H1SUSMC3, H1SUSPRM, H1SUSPR2, H1SUSPR3 have been copied to and committed in the userapps repository, under
/opt/rtcds/userapps/release/sus/h1/filterfiles/