SGP/SIRS/E21 - Tracker inoperative

The solar tracker at this site had numerous failures over the time range of this DQR.  The 
result is non-recoverable data for any direct normal (NIP) or diffuse (8-48) broadband 
measurement.  Longwave data is generally unaffected by such failures.

Data are not recoverable.

• Instantaneous direct normal shortwave irradiance, pyrheliometer thermopile
  voltage(inst_direct_normal)
• Instantaneous uncorrected downwelling shortwave diffuse, shaded pyranometer
  thermopile voltage(inst_diffuse)

• Downwelling shortwave diffuse hemispheric irradiance, pyranometer, maxima(down_short_diffuse_hemisp_max)
• Shortwave direct normal irradiance, pyrheliometer(short_direct_normal)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Standard Deviation(short_direct_normal_std)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Pyrgeometer, Minima(down_short_diffuse_hemisp_min)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Pyranometer, Standard
  Deviation(down_short_diffuse_hemisp_std)
• Shortwave direct normal irradiance, pyrheliometer, minima(short_direct_normal_min)