SGP/SIRS/E7 - NIP connector failure

After instrument replacement 8/5/2010 approx 1700GMT the short_direct_normal values became 
intermittent due to a failed NIP connector. Ops repaired the connector on 8/10 
rectifying the problem.

The short_direct_normal (NIP instrument) data are not recoverable during this period. 
Although there will be greater uncertainty the short_direct_normal can be reconstructed from 
the global and diffuse measurements for each minute of 
data using the following relationship:
down_short_hemisp = short_direct_normal*cos(zenith angle) + down_short_diffuse.

• Instantaneous direct normal shortwave irradiance, pyrheliometer thermopile
  voltage(inst_direct_normal)

• Shortwave direct normal irradiance, pyrheliometer(short_direct_normal)
• Shortwave direct normal irradiance, pyrheliometer, minima(short_direct_normal_min)
• Shortwave Direct Normal Irradiance, Pyrgeometer, Standard Deviation(short_direct_normal_std)
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)