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--- experimentaldata [2021/01/07 02:19]
sz
+++ experimentaldata [2021/02/05 16:57] (current)
sz ↷ Page name changed from experimenetaldata to experimentaldata
@@ Line 18: / Line 18: @@
 The file is switched based on Linux local time, which means that files are switched based on Daylight Savings time in the summer.
-The file name of these file contains the date when the file was opened.
+The file name of these files contains the date when the file was opened.
 The format of the file name, with leading directories is:
@@ Line 25: / Line 25: @@
 where yyyy is year, mm is month from 01 to 12, and dd is day from 01.
 The "A" following dd is a sequence letter within day.
-If the collection is interrupted, this character is changed for a continuation file with the same date.
+If the collection is interrupted, this character is manually changed for a continuation file with the same date.
+One day has 24*60*60 = 86,400 seconds. There are four or five samples per second.
+Therefore there are over 345,600 samples per file, or samples per day.
+The data format in the files is that of Mathematica; the entire file is a list of lists. Each inner list is a sample except the beginning ones are comments. The beginning of the file is as follows
+  {
+   {" program mainstore.py "},
+  {" File Name: /Users/stevenzins/Google Drive/gsync1/FOMMX/data/ZinsB20200126AR.txt "},
+  {" File Start Time: Sun Jan 26 00:00:00 2020 "},
+  {" Series Start Time: Sat Jan 25 15:56:15 2020 "},
+  {" type staq is Seconds, Turns, Azimuth, Quadrants "},
+  {" Seconds is since Linux Epoch"},
+  {" azimuth_of_house_axis = 333.2 "},
+  {"stdq", 1580022000.35, 484, 114.26, -1412},
+  {"stdq", 1580022000.58, 484, 115.58, -1411},
+  {"stdq", 1580022000.81, 484, 116.89, -1411},
 ==== Resampled Data Files ====
 These files are derived from the Original files.
 The data is resampled from about 4-5 samples per second in the Original files to exactly one sample per second in the Resampled file.
 The data format in the files has also been changed to comma separated variables (CVS).
 While the Original files may have part(s) of a day missing, these files have only complete days.
-If someone wanted to do their own analysis of the data, this would be the set of files to use.
 The format of the file name, with leading directories is:
@@ Line 52: / Line 69: @@
   * turns - Whole rotations of the rotor of the interferometer, derived from rotary encoder.
   * azrotor - Azimuth of the rotor, in degrees, derived from rotary encoder.
-    * Azimuth is zero  when the arm with black tape is at true North.
+    * Azimuth is zero  when the interferometer arm with black tape is at true North.
     * Azimuth increases when the arm with black tape moves from North toward East.
   * cumazrot - turns * 360 + azrotor
@@ Line 58: / Line 75: @@
     * A phase difference of one quarter of a cycle, or of a wavelength, is one quadrant.
     * The quadrant value is the count of quadrants detected since the collection program on the interferometer rotor began execution.
-    * A quadrant is one quarter of a full light-dark fringe shift cycle of mirror-style interferometers.
+    * A quadrant corresponds to one quarter of a full light-dark fringe shift cycle of mirror-style interferometers.
@@ Line 88: / Line 105: @@
 The second and third frame each present the azimuth of the data found by a modified Fourier analysis.
-A normal Fourier analysis test for the phase and amplitude of a wide range of frequencies.
+A normal Fourier analysis test for the phase and amplitude of a wide range of periods.
-Each of these two frames show a test for a single frequency.
+Each of these two frames show a test for a single period.
 This approach is called the [[wp>Goertzel algorithm]].
 The interferometer rotor rotates once a minute.
-The middle frame, labeled "Azimuth Full" uses the single frequency of once a minute.
+The middle frame, labeled "Azimuth Full" uses the single period of one full turn.
-The bottom frame, labeled "Azimuth Half" uses the single frequency of twice a minute,
+The bottom frame, labeled "Azimuth Half" uses the single period of one half turn.
-so the period is one half.
-==== Gallery of all Plots ====
+==== Gallery of Plots ====
-[[:gal2020a|Plots of all Resampled data]]
+[[:gal2020a|Gallery of Plots of all Resampled Data]]
+===== Collection periods, gaps, errors =====
+The collection period, described above, was January through June, 2020, about 180 calendar days.
+Resampled Data files were generated with a full 24 hours of data.
+There are about 30 days where the Original Data files had less than a complete 24 hours of data and were not plotted.
-===== [Collection periods, gaps, errors, full/partial] =====
+Most of the gaps may have been due to utility power outages. Loss of power for a fraction of a second was enough to cause the iMac to stop requesting data or shut down. Loss of power for a very few seconds would also shut down the Raspberry Pi, with loss of the accumulated quadrant count. In both cases, manual intervention was required to resume data collection.
-===== [Resampled Data Files, Availability] =====
+One large gap occurred from 20200417 through 20200428. This was due to the mechanical failure of the main thrust bearing that holds up the rotor and allows it to turn. The length of the down time was due mainly to the search for a better replacement part, the wait for delivery, and the installation of the replacement. While the collection was interrupted, I tried to examine the individual arm light output by connecting the fiber to an oscilloscope. In the process of doing this I inadvertently reversed the reconnections the two arms. The effect of this was to reverse the suspected Frame Drag component from -sin(24 hours) to +sin(24 hours). It probably also reversed the direction of the quadrant counter, but I am not certain of that.
-===== [Data Collection Software] =====
+===== Data File Availability =====
+The Original and Resampled data files are available upon request.
+The Original file set has has a little more data; the Resampled files have no gaps on any day.
+The Resampled files occupy about 4-4.6 MB each while the Original files occupy up to 17.9 MB.
+{{tag>pub}}

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