aLIGO LHO Logbook

H2 SEI

fabrice.matichard@LIGO.ORG - posted 10:47, Friday 27 July 2012 - last comment - 17:01, Friday 27 July 2012(3623)

ISC signals to HEPI

The ISC signals have been added to the ETMY HEPI model. Changes have been committed to the svn. The model has been successfully compiled and installed. We should be ready to offload.

Comments related to this report

fabrice.matichard@LIGO.ORG - 17:01, Friday 27 July 2012 (3636)

Link

To offload to HEPI we need to low pass the cavity signal before to add it to the HEPI longitudinal super-sensor. We made preliminary measurements this morning to check the Cavity and HEPI signs and units, but we need to refine the drive parameters. The template is saved in:

/ligo/svncommon/SeiSVN/seismic/HEPI/H2/ETMY/Misc/DTT_Cavity_offload

What we need to do next week:

- adjust the measurement parameters to get good coherence
- tune the gains and check the signs to put the signals in the same unit
- design the low pass filters. We plan to make a very low frequency one, to reject tidal motion. And a higher frequency one to reject the motion amplification due to ISI gain peaking (around 30 mHz)
- measure the open loops (ISC, HEPI, and the sum of the two)