SGP/MFRSR/E4 - Bad head temp and voltage data

Detector voltage and head temperature were erratic and at times wholly incorrect.  The 
first sign of this is on 20040524 just after 2000 UTC.  Sporadic irregularities are not 
altogether unusual, so by itself this is an incident of not much concern.  As time went on, 
however, the erratic readings become more frequent and the head temperature began to be 
affected as well.  Ultimately the problem was traced to a faulty signal cable.

The cable was replaced on 20050921 and the head temperature immediately responded with 
normal readings.  The voltage was still a little noisy for a few days, but ultimately reads 
near constant as expected.  Not sure why the voltage was still noisy for those days, but 
it could either be within normal bounds for this instrument, or possibly the new cable 
wasn't making a good connection at first.

The good news is the mentor believes the irradiance data during the time covered by this 
DQR are good, so this issue should be essentially transparent to the data user.

• Detector Temperature(head_temp)
• Data Logger Supply Voltage(logger_volt)

• Detector Temperature(head_temp)
• Data Logger Supply Voltage(logger_volt)

• null(Raw data stream - documentation not supported)

SGP/MFRSR/E4 - Offset contamination at sunrise/sunset

The 415 nm filters, 500 nm filters, & 673 nm filters were flatlining in the morning and 
late afternoon hours.  The flatlining is an artifact of the ingest. Nighttime offsets are 
determined each night and added back to the following day's data. If the offset is large 
negative, it will report the offset value until the data in the day go positive. When the 
instrument is running in shadowband mode negative values are not reported, resulting in 
the flatline behavior.  This issue is generally only seen just after sunrise and just 
before sunset on cloudy/overcast days.

• Direct Normal Narrowband Irradiance, Filter 4(direct_normal_narrowband_filter4)
• Alltime Narrowband Hemispheric Irradiance, Filter 2(alltime_hemisp_narrowband_filter2)
• Narrowband Direct Horizontal Irradiance, Filter 4(direct_horizontal_narrowband_filter4)
• Ratio of direct_normal_narrowband_filter2 to diffuse_hemisp_narrowband_filter2(direct_diffuse_ratio_filter2)
• Ratio of direct_normal_narrowband_filter1 to diffuse_hemisp_narrowband_filter1(direct_diffuse_ratio_filter1)
• Alltime Narrowband Hemispheric Irradiance, Filter 4(alltime_hemisp_narrowband_filter4)
• Narrowband Hemispheric Irradiance, Filter 2(hemisp_narrowband_filter2)
• Direct Normal Narrowband Irradiance, Filter 2(direct_normal_narrowband_filter2)
• Ratio of direct_normal_narrowband_filter4 to diffuse_hemisp_narrowband_filter4(direct_diffuse_ratio_filter4)
• Narrowband Direct Horizontal Irradiance, Filter 2(direct_horizontal_narrowband_filter2)
• Narrowband Hemispheric Irradiance, Filter 1(hemisp_narrowband_filter1)
• Direct Normal Narrowband Irradiance, Filter 1(direct_normal_narrowband_filter1)
• Narrowband Hemispheric Irradiance, Filter 4(hemisp_narrowband_filter4)
• Narrowband Diffuse Hemispheric Irradiance, Filter 4(diffuse_hemisp_narrowband_filter4)
• Alltime Narrowband Hemispheric Irradiance, Filter 1(alltime_hemisp_narrowband_filter1)
• Narrowband Diffuse Hemispheric Irradiance, Filter 1(diffuse_hemisp_narrowband_filter1)
• Narrowband Direct Horizontal Irradiance, Filter 1(direct_horizontal_narrowband_filter1)
• Narrowband Diffuse Hemispheric Irradiance, Filter 2(diffuse_hemisp_narrowband_filter2)

• Narrowband Direct Horizontal Irradiance, Filter 4(direct_horizontal_narrowband_filter4)
• Narrowband Diffuse Hemispheric Irradiance, Filter 1(diffuse_hemisp_narrowband_filter1)
• Narrowband Diffuse Hemispheric Irradiance, Filter 2(diffuse_hemisp_narrowband_filter2)
• Narrowband Direct Horizontal Irradiance, Filter 2(direct_horizontal_narrowband_filter2)
• Alltime Narrowband Hemispheric Irradiance, Filter 4(alltime_hemisp_narrowband_filter4)
• Alltime Narrowband Hemispheric Irradiance, Filter 1(alltime_hemisp_narrowband_filter1)
• Narrowband Direct Horizontal Irradiance, Filter 1(direct_horizontal_narrowband_filter1)
• Alltime Narrowband Hemispheric Irradiance, Filter 2(alltime_hemisp_narrowband_filter2)
• Narrowband Hemispheric Irradiance, Filter 2(hemisp_narrowband_filter2)
• Narrowband Diffuse Hemispheric Irradiance, Filter 4(diffuse_hemisp_narrowband_filter4)
• Narrowband Hemispheric Irradiance, Filter 1(hemisp_narrowband_filter1)
• Narrowband Hemispheric Irradiance, Filter 4(hemisp_narrowband_filter4)