DQRID : D060915.2
Start DateStart TimeEnd DateEnd Time
08/29/2006190001/30/20070010
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Subject:
TWP/TSI/C1 - solar shadowband inoperative
DataStreams:twptsiskycoverC1.b1, twptsicldmaskC1.a1, twptsimovieC1.a1, twptsiskyimageC1.a1
Description:
The mirror/shadowband was not turning and there was no communication with the control 
board. The shadowband was stuck in the position of 0 degrees from 8/29 to 9/20/2006.

On 10/12/2006, the mirror was replaced, the real-time clock chip was removed and heat 
sinks were added to the control board, and the Ethernet hub and serial adaptor were replaced. 
On 1/8/2007, the slip clutch assembly, timing pulley, and timing belt were replaced 
(which were damaged when the mirror was replaced). These actions did not correct the problem. 
The instrument was swapped with the unit from Darwin so that the control board could be 
repaired and tested in Darwin.

Several images were collected in the iterim that should be ignored. These images include 
periods when the sun was not masked by the shadowband or the camera lens was covered by 
tape to protect the CCD from direct
exposure to the sun. There are also extended periods of missing data when the instrument 
was shutdown, waiting for parts.
Suggestions: 
null
Measurements:twptsiskycoverC1.b1:
  • Percent opaque cloud(percent.opaque)
  • Pixel count: number total in zenith circle(region.zenith.count)
  • time_in_seconds_since_volume_start(time)
  • -180.0 - +180.0(alt)
  • Solar azimuth angle(solar.azimuth)
  • Time offset from base_time(time_offset)
  • Relative \'strength\' of direct sun(sun.strength)
  • Pixel count: number total in processed circle(count.sky)
  • Pixel count: camera and sun strip mask(count.mask)
  • Pixel count: number total opaque(count.opaque)
  • Pixel count: number total thin(count.thin)
  • Pixel count: number opaque in zenith circle(region.zenith.count.opaque)
  • Pixel count: number thin in horizon area(region.horizon.count.thin)
  • Pixel count: number opaque in sun circle(region.sun.count.opaque)
  • Pixel count: number total indeterminant(count.unknown)
  • Pixel count: number total between horizon and processed circle(count.sub.proczen)
  • Pixel count: number thin in sun circle(region.sun.count.thin)
  • Pixel count: number thin in zenith circle(region.zenith.count.thin)
  • lon(lon)
  • Sun altitude above horizon(solar.altitude)
  • Sunshine meter(sunny)
  • Percentage thin cloud(percent.thin)
  • Pixel count: number total in sun circle(region.sun.count)
  • Pixel count: number total in horizon area(region.horizon.count)
  • North Latitude(lat)
  • Pixel count: number opaque in horizon area(region.horizon.count.opaque)
  • base time in epoch(base_time)
  • Pixel count: number below horizon in image(count.sub.horz)
  • Pixel count: box, outside mirror area(count.box)
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twptsiskyimageC1.a1:
  • null(JPEG data stream - documentation not yet available)
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twptsicldmaskC1.a1:
  • PNG data stream - documentation not supported(png)
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twptsimovieC1.a1:
  • (MPEG data stream - documentation not yet available)
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