SGP/SIRS/E18 - NIP condensation problem

NIP at E18 was measuring impossible values due to condensation on inside of NIP window.  
PM replaced NIP 2/26/2008 2150.

Measured data are not recoverable.  Use component sum method to reconstruct NIP data.  NIP 
= (Global-Diffuse)/cos(ZA)

• inst_direct_normal

• short_direct_normal
• short_direct_normal_min
• short_direct_normal_max
• short_direct_normal_std