Reports until 15:12, Thursday 26 September 2019
H1 ISC (GRD, Lockloss)
adrian.helmling-cornell@LIGO.ORG - posted 15:12, Thursday 26 September 2019 - last comment - 19:47, Saturday 26 October 2019(52150)
Lockloss Trigger Updated

Jenne Driggers, Adrian Helmling-Cornell

Today we updated the photodiode used for the frontend lockloss trigger from POP_A_DC to POPAIR_A_DC, as it responds slightly faster to the interferometer losing lock. The lockloss trigger is armed when Guardian enters the OFFLOAD_DRMI_ASC state. As Guardian goes through the CARM offset reduction sequence, if POPAIR_A normalized by the laser power falls below 2.5 the lockloss trigger will now trigger, stopping actuation. When Guardian reaches and passes the DRMI_TO_POP state, the trigger triggers if POPAIR_A normalized by the laser power falls below 108.

The appropriate SDF diffs were accepted and this change was implemented around 20:40 UTC today.

Comments related to this report
sheila.dwyer@LIGO.ORG - 19:47, Saturday 26 October 2019 (52707)

We are undoing this change for now so that we have the option of closing the beam diverter.