J. Kissel

During the furious model re-arrangement this morning, I took the opportunity to remove IMC X channels from the top level of the MC2 front end model. After the changes to the front end model, this required a recompile, reinstall, restart and restore. The IMC is now locked happily.

I want to remove these channels because they are now to be derived in the CAL model, like every other of the IFO's cavity length signals. I'm still in the process of creating a set calibration filter that makes sense for the actuation chain. I would copy and paste what's in the IMC X bank, or what's in the OAF bank, but it turns out the filters that have been in use since Apr 2013 (LHO aLOG 5945) have been wrong. Namely, the M3 stage filter is a copy of the M1 stage filter. The M3 stage filter should (at least) fall off as 1/f^2, which, of course, the M1 stage filter does not. Further, this has been copied, in one way or another to every other place where we've tried to calibrate the IMC length signal since, i.e. the OAF model. 

So, I'm trying to break the cycle, and stick in sensible filters, and even update them with the what ever current non-sense damping scheme we're using by applying the real damping filters and gains to the SUS model. BUT I'm running onto the classic problem of turning something in matlab into something that foton will chew on. Mostly it's because basic functions like minreal and zpkdata are not cancelling right-half-plane poles in a sane way. I'll bang my head on this more tomorrow. If you want to fight with me, check out
/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/MC2/Common/H1SUSMC2_GlobalTFs_to_Foton_20150224.m

Two plots attached:
- the bad IMC X / OAF calibration filters.
- What the transfer function should look like for MC2 with the current filters and gains.

Screenshot shows that the three outputs near the bottom of the main, yellow, MC2 block -- M1, M2, and M3 _LOCK_L_Outs -- are now terminated.

I've committed the changes to the userapps repo,
jeffrey.kissel@operator1:/opt/rtcds/userapps/release/sus/h1/models$ svn commit -m "Removed IMC X calibration channels from top level. These will now be calcuated in CAL-CS." h1susmc2.mdl 
Sending        h1susmc2.mdl
Transmitting file data .
Committed revision 9902.