Attached are the long trends of the ETM charge measurements with this morning's data appended. Note in the first 2 plots that the ETMy charge looks slighly ramped up as it heads away from zero in all 4 quadrants - if indeed ramping, it could be due to the nice IFO duty cycle we have which drives through the ETMY L3. For this reason, Jenne wrote into the ISC_LOCK.py Guardian to set the ETMY L3 bias gain in DOWN to be the opposite of what it is in-lock in an attempt to de-charge it when not in low noise use. She also made sure the there was an appropriate re-setup step for this bias gain where needed in the guardian script.
This is a similar change that Sheila made in alog 31172 to "de-charge" ETMX via flipping the gain sign during unused times - in that case during low noise locking.
Change to the guardian script has been committed to SVN.
J. Kissel, S. Dwyer We've further modified the LOWNOISE_ETMY_ESD state to wait for this LOCK_BIAS gain change to finish ramping before moving to the transition. Also, now the transition of control to ETMY (after the bias has successfully flipped sign) happens in the run portion of the state as opposed to the main, with a couple of more counters that wait for all the appropriate 30 second ramps to finish. This means that it's going to take 30 seconds longer to go through this state. Your patience is appreciated! We've successfully transitioned over to ETMY using this further updated code.