Operator Log
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This page is a time ordered list of entries made to record significant events in the operation of the magnetometer. The list is in reverse time order, that is, the most recent entry is at the top of the list.
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15 May 2003 UTC
- 00:00 MDT - 06:00 UTC - NCEMO data acquisition halted
- Data acquisition at NCEMO has been terminated because of a planned move of the residence surrounding the observatory. This termination shall continue until a suitable, new location can be found.
- Data archives, construction details, and other related materials shall remain available during this period.
JAD
1 April 2003 UTC
- 22:21 UTC - entered the magnetometer enclosure
- Restored lock by adjusting detector and reseting integrator
JAD
24 March 2003 UTC
- 00:00 UTC - entered the magnetometer enclosure
- Restored lock by adjusting nulling magnets and reseting integrator
JAD
19 March 2003 UTC
- 03:00 UTC - Main AC power bounce causes control loop "goes out of lock"
JAD
27 January 2003 UTC
- 00:00 UTC - Updated web site
- Now using SSI (Server Side Includes) to include boilerplate common to every page.
- Now using more CSS (Cascading Style Sheets) to make navigation bar and links more clearly identified.
- Changed "Most Recent Data" display to show all three current hourly graphs.
JAD
01 November 2002 UTC
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20:00 UTC - The global data filter algorithm has been modified. The gory details follow:
- Each recorded analog signal is hardware filtered before digitization with a single-pole, 1Hz, low pass anti-aliasing filter.
- Each digitized data stream (corresponding to one analog signal) is subjected to stored calibration data to convert the raw voltages to meaningful measurements.
- Archived text data is not subjected to digital filtering and is stored exactly as recorded with the calibrations applied.
- Plotted data is subjected to additional digital filtering with a rectangular window-based filter.
- A different filter window is used for graphs with different time axes.
- The plotted data filter window was previously set to 1, 6, and 24 seconds for the 1, 6, and 24 hour graphs, respectively.
- With this change, the plotted data filter window is now set to 6, 36, and 144 seconds for the 1, 6, and 24 hour graphs, respectively.
- Previously and currently and in all graphs exactly 600 time points are plotted.
- The plotted data was previously under-filtered by a factor of 6 in time.
- With this change, the plotted data is now optimally filtered - consistent with the number of plotted data points.
- With this change, there is no change in the time resolution of the plotted data.
- With this change, there is a roughly two-fold increase in the signal-to-noise ratio.
JAD
10 August 2002 UTC
- 16:45 UTC - Repaired broken wires to external temperature sensor
JAD
9 July 2002 UTC
- 15:10 UTC - Entered the magnetometer enclosure
- Reset loop to restore lock
JAD
4 July 2002 UTC
- 22:00 UTC - Entered the magnetometer enclosure
- Repositioned detector to reset EW field
JAD
2 June 2002 UTC
- 20:30 UTC - Restored power
- Entered the magnetometer enclosure
- Repositioned detector to reset EW field
- 17:50 UTC - Turned off power to magnetometer for unrelated periodic maintanence
JAD
20 May 2002 UTC
- 21:10 UTC - entered the magnetometer enclosure
- Repositioned nulling magnet to reset EW field
JAD
20 May 2002 UTC
- 11:06 UTC - control loop "goes out of lock" as evidenced by loss of laser signal and pinning of magnetometer signal to rail
JAD
30 July 2001 UTC
- 09:10 UTC - Entered the magnetometer enclosure, centered Field Signal by repositioning Nulling Magnet Assembly, and closed magnetometer enclosure
- 09:20 UTC - Repositioned external temperature sensor to reduce periodic interference by local sprinklers
JAD
8 June 2001 UTC
- 08:50 UTC - Entered the magnetometer enclosure, centered Field Signal by repositioning Nulling Magnet Assembly, and closed magnetometer enclosure
JAD
6 May 2001 UTC
- 22:30 UTC - Entered enclosure for examination only and closed immediately
JAD
29 April 2001 UTC
- 23:50 UTC - Repaired wires leading to external temperature sensor having been gnawed apart
JAD
3 April 2001 UTC
- 01:00 UTC - Entered the magnetometer enclosure, reset integrator, and closed magnetometer enclosure
JAD
2 April 2001 UTC
- 21:30 UTC - Lost lock due to unusually large activity
JAD
22 March 2001 UTC
- 00:30 UTC - Entered the magnetometer enclosure, reset integrator, and closed magnetometer enclosure
JAD
20 March 2001 UTC
- 14:15 UTC - Lost lock due to unusually large activity
JAD
30 January 2001 UTC
- 22:20 UTC - Adjusted Drive Coil gain magnitude to correct a long-standing computational error (Thanks to Prof. Gerard T. Blanchard)
- Updated processing program to improve y-axis labels
JAD
23 January 2001 UTC
- Updated processing and listing programs to reflect a change from GIF graph files to PNG graph files
- Old GIF files are still displayed, newly created files are in PNG format
JAD
18 September 2000 UTC
- 21:00 UTC - entered the magnetometer enclosure
- Replaced TBM with new version containing corrected (EW) Drive Coils and Adjustable Damping
- Replaced Detector with new version featuring a linear deflection response
- Adjusted nulling magnet to reset EW field, insured that NS field was nulled as evidenced by lengthening of TBM period
- Adjusted damping to approximately critical damping
- Increased Loop Gain to maximum without inducing loop oscillation
- 22:00 UTC - closed the magnetometer enclosure
JAD
15 September 2000 UTC
- 18:25 UTC - entered the magnetometer enclosure
- Repositioned detector to trim EW field and recenter Field data
- Touched up Loop Gain to maintain loop on edge of oscillation
- 18:35 UTC - closed the magnetometer enclosure
JAD
14 September 2000 UTC
- 21:35 UTC - entered the magnetometer enclosure
- Found that the control loop had "gone out of lock"
- Repositioned nulling magnet to reset EW field, insured that NS field was nulled as evidenced by lengthening of TBM period
- Removed tape mask from detector face to permit evaluation of its effect on the Laser signal
- 22:05 UTC - closed the magnetometer enclosure
JAD
11 September 2000 UTC
- 03:30 UTC - recording was disabled for recabling the serial interconnect between the magnetometer enclosure and the workshop computer
- 05:55 UTC - recording restored
JAD
10 September 2000 UTC
- 18:00+ UTC - groundskeeping work (read: mowing the lawn)
JAD
3 September 2000 UTC
- 15:15 UTC - main power was turned off to the enclosure and logging computer for reasons unrelated to the magnetometer
- 15:28 UTC - main power was restored
JAD
23 August 2000 UTC
- 15:15 UTC - entered the magnetometer enclosure
- Inserted voltage divider (x0.5) on Field Signal in front of ADC to eliminate recently observed clipping of Field Signal
- Repositioned nulling magnet to (1) decrease restoring field and (2) recenter zero point
- Adjusted loop gain to account for change in restoring field
- 15:33 UTC - closed the magnetometer enclosure
- 15:40 UTC - adjusted logging program calibration constant to account for voltage divider and restarted logging program
JAD
20 August 2000 UTC
- 18:24 UTC - Creation of log and initial entry.
JAD
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