solar tracker inoperative

On about 97/04/12 the solar tracker at site E2 stopped working.  The
solar tracker exhibits its broken state in a particular striking fashion on 97/04/14 - an 
almost
cloud-free day.  On this day, the NIP reads zero and the diffuse and
direct SW radiation are about the same.  The fact that these two data steams
are not exactly the same indicates a calibration problem - probably with
the diffuse instrument.  This poor calibration is not typical of other
ARM sites!  On about 97/04/17 (1400 GMT) the solar tracker was fixed.

(Note: we cannot pinpoint the exact time or date when the solar tracker
went out and the date quoted above {97/04/12} should be regarded
as approximate)

• lon(lon)
• Ventilated Pyrgeometer Dome Temperature(down_long_dome_temp)
• Downwelling Longwave Diffuse Hemispheric Irradiance, Ventilated Pyrgeometer(down_long_diffuse_hemisp)
• Data Logger Temperature(logger_temp)
• Diffuse Hemispheric Irradiance, MFRSR(diffuse_hemisp_narrowband)
• Thermistor Excitation Voltage, Data Logger(therm_volt)
• Down-welling unshaded pyranometer voltage(down_short_hemisp)
• Ventilated Pyrgeometer Case Temperature(down_long_case_temp)
• Direct Normal Irradiance, MFRSR(direct_norm_broadband)
• 25 meter Longwave Case Temperature, Pyrgeometer(up_long_case_temp)
• 10 meter Longwave Dome Temperature, Pyrgeometer(up_long_dome_temp)
• Flag fields with *2 returned from callang(flag_ln_error1-24)
• Data logger supply voltage(logger_volt)
• base time in epoch(base_time)
• Direct Normal Irradiance, NIMFR(direct_norm_narrowband)
• Flag fields with *4 returned from callang(flag_nighttime1-24)
• Time offset from base_time(time_offset)
• MFRSR channels(channel)
• -180.0 - +180.0(alt)
• Flag fields with *3 returned from callang(flag_zero_cosine1-24)
• North Latitude(lat)
• Shortwave direct normal irradiance, pyrheliometer(short_direct_normal)
• Flag fields with *1 returned from callang(flag_zero_divisor1-24)
• Hemispheric broadband irradiance(hemisp_broadband)
• Downwelling Shortwave Diffuse Hemispheric Irradiance, Ventilated Pyranometer(down_short_diffuse_hemisp)
• 25 meter Upwelling Shortwave Hemispheric Irradiance, Pyranometer(up_short_hemisp)
• Diffuse Hemispheric Broadband Irradiance, offset corrected(diffuse_hemisp_broadband)
• 10 meter Upwelling Longwave Hemispheric Irradiance, Pyrgeometer(up_long_hemisp)
• MFRSR Detector Temperature(mfrsr_temp)
• Hemispheric Irradiance, MFRSR(hemisp_narrowband)