TWP/VCEIL/C3 - standard instrument installed

A spare ceilometer without the tropics window option was installed. The manufacturer 
recommends the tropics window be used at +/- 25 deg lattitude to prevent direct solar 
radiation into the laser optics when the instrument pointed at zenith. No significant signal 
degradation is apparent during the autumnal equinox but, as a precaution, the unit was 
replaced with the original with a tropics window.

• Vertical visibility(vertical_visibility)
• Aerosol volume backscattering coefficient at 355 nm(backscatter)
• Laser temperature(laser_temperature)
• Percentage of nominal factory setting (0 to 999%)(laser_pulse_energy)
• Sum of detected and normalized backscatter(sum_backscatter)
• Millivolts at internal ADC input (0 to 2500)(background_light)