We tried to perform the DRMI commissioning.
After the initial alignment, we can lock the DRMI by guardian.
We measured the OLTF for MICH, we noticed that the UGF was about 6 Hz (Previous 10 Hz?)
When we changed the MICH gain twice, the DRMI became unstable.
After back to the original values, the DRMI became unstable (alignment became bad??), so we gave up more commissioning this morning.
As reported yesterday, when we turned off the ADS of BS P,Y, DRMI seemed stable.
I measured the spectrum of the MICH, PRCL and SRCL error signals.
Status of resG
MICH1 FM4 off resgain(11.1,50,60)resgain(15.1,50,60)
PRCL1 FM4 on resgain(9.1,50,60)resgain(8.1,50,60)resgain(4.3,50,60)resgain(6.3,50,60)resgain(11.1,50,60)resgain(15.1,50,60)
SRCL1 FM4 on resgain(4.3,50,60)resgain(6.3,50,60)
Fig.1. and Fig.2. showed the spectrum around the IMMT2 dither (P 38.1 Hz and Y 22.1 Hz)
MICH, PRCL and SRCL can be seen the peaks
Fig.3. showed the spectrum around the SRM dither (P 4.3 Hz and Y 6.3 Hz)
resG for ADS seemed working for PRCL and SRCL, but not implemented to MICH
Fig.4. showed the spectrum around the PRM dither (P 9.1 Hz and Y 68.1 Hz)
resG for ADS seemed working for PRCL, small peak can be seen in SRCL, large peak can be seen in MICH
Fig.5. showed the spectrum around the BS dither (P 11.1 Hz and Y 15.1 Hz)
resG for ADS seemed working for PRCL, large peak can be seen in SRCL and MICH
Fig.1. showed the MICH error signal before(dash) and after(solid) the FM4 (resG) turned on.
Actually, the peaks of ADS frequency disappeared, but lock would be unstable (~1.5 min, Fig.2.), BS Y fluctuated a lot in 0.1 Hz
