DQRID : D030117.27
Start DateStart TimeEnd DateEnd Time
07/01/2002000007/11/20021300
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Subject:
SGP/EBBR/E26 - Multiplexer Problem
DataStreams:sgp30ebbrE26.b1, sgp5ebbrE26.b1, sgp15ebbrE26.b1
Description:
One of the multiplexers exhibited dropouts of the channels, beginning
with the last channel at temperatures above about 30 C and moving backward
through the channels as the temperature rose. High temperatures affected the
switching speed of the multiplexer.  This is the first time that this behavior has been 
documented in a Campbell Scientific multiplexer. The multiplexer had
been in continuous field use for 10 years and had experienced probably more
switching cycles than what is normally expected of the device in that period.

The multiplexer was replaced to solve the problem.
Suggestions: 
The data needs to be inspected by the user to determine which measurements
are still useful.  It helps to remember that the multiplexer behavior is
temperature dependent.
Measurements:sgp5ebbrE26.b1:
  • Bottom air temperature(temp_air_bottom)
  • Top air temperature(temp_air_top)
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sgp15ebbrE26.b1:
  • Right air temperature(temp_air_right)
  • Left air temperature(temp_air_left)
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sgp30ebbrE26.b1:
  • Surface soil heat flux 5(surface_soil_heat_flux_5)
  • Top air temperature(temp_air_top)
  • Surface latent heat flux(latent_heat_flux)
  • Surface soil heat flux 3(surface_soil_heat_flux_3)
  • Surface soil heat flux 4(surface_soil_heat_flux_4)
  • Bottom air temperature(temp_air_bottom)
  • Soil heat flow 5, corrected for soil moisture(corr_soil_heat_flow_5)
  • Surface soil heat flux 1(surface_soil_heat_flux_1)
  • Soil heat flow 2, corrected for soil moisture(corr_soil_heat_flow_2)
  • Surface soil heat flux 2(surface_soil_heat_flux_2)
  • Soil heat flow 1, corrected for soil moisture(corr_soil_heat_flow_1)
  • Soil heat flow 4, corrected for soil moisture(corr_soil_heat_flow_4)
  • Soil heat flow 3, corrected for soil moisture(corr_soil_heat_flow_3)
  • Surface sensible heat flux(sensible_heat_flux)
  • Surface soil heat flux, average of fluxes 1-5(surface_soil_heat_flux_avg)
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