SGP/NIMFR/C1 - Tube heater not functioning

The tube heater is not functioning properly. On 6/27/06, site operations personnel 
indicated the heater plug was found to be disconnected (The heater became disconnected on 
6/12/06).  It was reconnected and while the head temperature returned to normal, the tube 
temperatures are still bad.

The purpose of the tube heater is to help prevent condensation from forming on the window. 
 The mentor has not noticed any problems with the data resulting from the tube heater 
malfunction.  However, since the instrument is technically not fully functional, this DQR 
is being issued.

A repair attempt was made on June 7, 2007 that resulted in the tube temperatures reaching 
at times into the upper 50s and sometimes even the lower 60s.  The high tube temps 
influenced the head temperature causing it to move into the upper 40s and sometimes the lower 
50s.

The heater was repaired on Oct 11, 2007.  Though repaired, the instrument was configured 
to keep the tube temp in the lower 20s (deg C).  This is acceptable, though to keep with 
instrument specifications the setting was adjusted to keep the temps in the upper 30s (deg 
C).  This occurred on 8 Jan, 2008.

For those times when the tube heater was not functioning, or it was
functioning but keeping temps in the lower 20s, users should be confident
using the data.  There was never any indication from field reports or by
looking at the data that the condensation was occurring on the front glass.

From June 6, 2007 to the repair on Oct 11, 2007, users should be somewhat
cautious of the data.  During this period the head temps were high and
possibly had an adverse effect on the data.  That said, the data plots look
fine but there may be subtle influences that are not obvious.

• Time offset from base_time(time_offset)
• time_in_seconds_since_volume_start(time)
• Direct Normal Broadband Irradiance, raw data as read(direct_normal_broadband_raw)
• Second detector temperature(head_temp2)
• Direct Normal Narrowband Irradiance, Filter 1, raw data as read(direct_normal_narrowband_filter1_raw)
• lon(lon)
• Direct normal narrowband irradiance, filter 2(direct_normal_narrowband_filter2_raw)
• Direct Normal Narrowband Irradiance, Filter 3, raw data as read(direct_normal_narrowband_filter3_raw)
• Tube Temperature(tube_temp)
• Direct normal narrowband irradiance, filter 4(direct_normal_narrowband_filter4_raw)
• Direct Normal Narrowband Irradiance, Filter 5, raw data as read(direct_normal_narrowband_filter5_raw)
• Direct Normal Broadband Irradiance, cosine corrected, broadband scale applied(direct_normal_broadband)
• Offset subtracted from hemispheric and diffuse broadband data(offset_broadband)
• Direct normal narrowband irradiance, filter 6, offset corrected(direct_normal_narrowband_filter6)
• Offset subtracted from hemispheric and diffuse filter6 data(offset_filter6)
• Offset subtracted from upwelling hemispheric filter5 data(offset_filter5)
• Direct Normal Narrowband Irradiance, Filter 6, raw data as read(direct_normal_narrowband_filter6_raw)
• Data logger supply voltage(logger_volt)
• base time in epoch(base_time)
• Offset subtracted from upwelling hemispheric filter2 data(offset_filter2)
• Offset subtracted from hemispheric filter1 data(offset_filter1)
• Offset subtracted from direct normal filter4 data(offset_filter4)
• Narrowband Direct Normal Irradiance, Filter 1(direct_normal_narrowband_filter1)
• Offset subtracted from direct normal filter3 data(offset_filter3)
• Narrowband Direct Normal Irradiance, Filter 3, cosine corrected(direct_normal_narrowband_filter3)
• North Latitude(lat)
• Direct normal narrowband irradiance, filter 2, offset corrected(direct_normal_narrowband_filter2)
• Narrowband Direct Normal Irradiance, Filter 5(direct_normal_narrowband_filter5)
• Direct normal narrowband irradiance, filter 4, offset corrected(direct_normal_narrowband_filter4)
• Detector temperature(head_temp)
• -180.0 - +180.0(alt)

• Nominal calibration factor, applied to filter3 data(nominal_calibration_factor_filter3)
• Nominal calibration factor, applied to filter4 data(nominal_calibration_factor_filter4)
• Nominal calibration factor, applied to filter1 data(nominal_calibration_factor_filter1)
• Nominal calibration factor, applied to filter2 data(nominal_calibration_factor_filter2)
• Nominal calibration factor, applied to filter5 data(nominal_calibration_factor_filter5)
• Nominal calibration factor, applied to filter6 data(nominal_calibration_factor_filter6)
• Azimuth angle(azimuth_angle)
• Elevation angle(elevation_angle)
• Data logger supply voltage(logger_volt)
• Narrowband Direct Normal Irradiance, Filter 1(direct_normal_narrowband_filter1)
• Normalized filter function data, filter 5, wavelength value obtained during
  bench calibrations(wavelength_filter5)
• Normalized filter function data, filter 6, wavelength value obtained during
  bench calibrations(wavelength_filter6)
• Narrowband Direct Normal Irradiance, Filter 3, cosine corrected(direct_normal_narrowband_filter3)
• Normalized filter function data, filter 3, wavelength value obtained during
  bench calibrations(wavelength_filter3)
• Direct normal narrowband irradiance, filter 2, offset corrected(direct_normal_narrowband_filter2)
• Normalized filter function data, filter 4, wavelength value obtained during
  bench calibrations(wavelength_filter4)
• Narrowband Direct Normal Irradiance, Filter 5(direct_normal_narrowband_filter5)
• Normalized filter function data, filter 1, wavelength value obtained during
  bench calibrations(wavelength_filter1)
• Normalized filter function data, filter 2, wavelength value obtained during
  bench calibrations(wavelength_filter2)
• Direct normal narrowband irradiance, filter 4, offset corrected(direct_normal_narrowband_filter4)
• Cosine solar zenith angle(cosine_solar_zenith_angle)
• Offset subtracted from upwelling hemispheric filter5 data(offset_filter5)
• Offset subtracted from hemispheric and diffuse filter6 data(offset_filter6)
• Detector temperature(head_temp)
• Second detector temperature(head_temp2)
• Nominal calibration factor, applied to broadband data(nominal_calibration_factor_broadband)
• base time in epoch(base_time)
• Direct horizontal narrowband irradiance, filter 1(direct_horizontal_narrowband_filter1)
• Narrowband Direct Horizontal Irradiance, Filter 2, cosine corrected(direct_horizontal_narrowband_filter2)
• Time offset from base_time(time_offset)
• Normalized filter function data, filter 4, measured transmittance value obtained
  during bench calibrations(normalized_transmittance_filter4)
• time_in_seconds_since_volume_start(time)
• Normalized filter function data, filter 3, measured transmittance value obtained
  during bench calibrations(normalized_transmittance_filter3)
• Normalized filter function data, filter 2, measured transmittance value obtained
  during bench calibrations(normalized_transmittance_filter2)
• Normalized filter function data, filter 1, measured transmittance value obtained
  during bench calibrations(normalized_transmittance_filter1)
• Direct Horizontal Broadband Irradiance(direct_horizontal_broadband)
• Offset subtracted from hemispheric filter1 data(offset_filter1)
• Offset subtracted from upwelling hemispheric filter2 data(offset_filter2)
• Offset subtracted from direct normal filter3 data(offset_filter3)
• Offset subtracted from direct normal filter4 data(offset_filter4)
• North Latitude(lat)
• Solar zenith angle(solar_zenith_angle)
• -180.0 - +180.0(alt)
• Normalized filter function data, filter 6, measured transmittance value obtained
  during bench calibrations(normalized_transmittance_filter6)
• Normalized filter function data, filter 5, measured transmittance value obtained
  during bench calibrations(normalized_transmittance_filter5)
• Direct normal narrowband irradiance, filter 6, offset corrected(direct_normal_narrowband_filter6)
• Tube Temperature(tube_temp)
• Direct Normal Broadband Irradiance, cosine corrected, broadband scale applied(direct_normal_broadband)
• Offset subtracted from hemispheric and diffuse broadband data(offset_broadband)
• Direct Horizontal Narrowband Irradiance, Filter 3(direct_horizontal_narrowband_filter3)
• Narrowband Direct Horizontal Irradiance, Filter 4, cosine corrected(direct_horizontal_narrowband_filter4)
• Narrowband Direct Horizontal Irradiance, Filter 5, cosine corrected(direct_horizontal_narrowband_filter5)
• lon(lon)
• Narrowband Direct Horizontal Irradiance, Filter 6, cosine corrected(direct_horizontal_narrowband_filter6)
• Air mass(airmass)