Summary: The interventions in late July and early August to disable blinking LEDs and isolate timing system power supplies
have made some difference in the periodicities that emerge when folding magnetometer data from the end stations, with the largest
difference seen with the initial firmware updates done in late July.
Details:
Weigang Liu has been cumulatively applying his folding algorithm to magnetometer data from January through
early August, including periods before, during and after recent attempts to mitigate leakage of periodic
(1 Hz and 0.5 Hz) transients seen in magnetometer channels into DARM. [Recent clogging of the Caltech
cluster nodes with sufficient memory has delayed the automatic production of these plots, so Weigang did
a bunch of jobs manually on head nodes for this report.]
Summary of recent interventions:
- July 19 - Upgrade of timing slave card firmware to disable alternating on/off blinking of LEDs with 2-second periodicity (on 1 second, off 1 second), suspected to lead to alternative positive / negative current transients that affect DARM.
- August 2 - Upgrade of EX timing fanout card firmware for same reason
- August 5 - Isolation of timing card power supplies
- August 9 - Upgrade of EY timing fanout card firmware
- August 16 - Additional timing card firmware upgrades in LVEA, EX, EY
The following table includes links to summary pages for most of the days to date of 2016 (some condor jobs still pending)
for six end-station magnetometer channels, along with comments on changes visible from July 16 to July 21, then to August 6, then to August 18,
along with figure attachment numbers showing the folded data plots for those days.