daniel.hoak@LIGO.ORG - posted 22:10, Sunday 12 July 2015 - last comment - 14:09, Monday 13 July 2015(19585)
Oooh those python indents
(Not Dan)
An accidental INDENTING change in the ISC_LOCK guardian affected a "return True" statement. Result:
- CARM_ON_TR returned true without actually ramping H1:LSC-REFL_SERVO_IN2GAIN to -32dB.
- This resulted in random lock losses later on in the lock sequence.
- This resulted in 6h of head scratching of the assembled commissioning team.
There is a long an ongoing discussion about the python indentation convention. No need to state which side the author of this log is on.
In the end we were able to bring the interferometer back into full, low-noise lock at 24 W. The DARM spectrum between 10 and 100 Hz is attached, along with the previous best. Of course, our actuator has changed since the vent, so the calibration must be redone. However, I have tried to make the comparison more fair by (1) making sure the DARM OLTF is the same as at the start of ER7, and (2) rescaling the calibrated control and error signals (in the frontend) to restore the heights of the pcal lines (the required rescaling seems to be about 1.2 for both control and error). I also adjusted the EY L3 drivealign calibration gain from -50 to -30, since that is what we now use in lock.
Dan, can you paste a diff of the offending indent code? Or point to a revision in the USERAPPS SVN? It would be instructive to see the code explicitly.