Timing Calibration
Jeff, Jim, Dave:
Jim synced up the atomic clock system to the NTP GPS receiver and then used it to sync the MCA unit which in turn drives the end station TCT units. The 1PPS originating from the MCA was connected to the first input of the MSR comparator. Jim also synchronized the original atomic clock to the same source, and we transported this unit (continually powered via UPS) to both end stations. At the end stations the time offset dip switches on the TCT units were changed to compensate for the TOF to the end stations. At the end stations the 1PPS coming from the TCT are being fed into the comparators, first channel.
We also connected the 1PPS from the NTP GPS to the second comparator input in the MSR.
A more detailed alog of these procedures is in the works.
PSL ISS model change:
Sudarshan and Jeff.
A new h1psliss model was created. This is a "stand alone" model, no common PSL parts are being used. Full details in Jeff and Sudarshan's alog.
HWS Beckhoff gain setting
Aidan, Elli, Nutsinee, Patrick
A HWS gain setting was incorrectly set as a read-only channel and therefore could not be changed from zero. Patrick has made this changeable and it is now 1.0
DMT channel list changed
John Z and Dave
John Zweizig requested a new DMT channel list be applied to the DAQ broadcaster, this was done at 15:00 local time.
LDAS Tape Robot Move
Greg, Dan, Jim, Dave
The LDAS tape robot was moved from the computer users room to the warehouse. Fiber optics cabling was added in the MSR between the warehouse patch panel and the Q-Logic switches in the DAQ racks.
Attached is a minute trend plot for 4 hours (midday to 4pm PDT) showing the MCA and TCT 1PPS time differences measured by the timing system comparators (which are clocked by the aLIGO timing system). In all three locations (MSR, EX and EY) the MCA and TCT 1PPS signals are connected to the first comparator channels.
All variations seen are due to the timing system itself (all three locations vary in the same way). At each station the range of variation is about 25-30nS over the 4 hours time period.
Both end stations are synchronized to within the 10nS resolution of the TCT.