This instrument is sampled at approximately 1 Hz at six minute intervals.

  Sample file format:
    yr mm da time pos flash     dark      dif          vis         extCo     urng  orng pts
  2008  3    1 1824   4  6.2047  6.1902  0.0145   151930   0.021186   0.0   5.0 319
  2008  3    1 1830   4  6.2027  6.1882  0.0145   148663   0.021497   0.0   7.1 340
  2008  3    1 1836   4  6.1896  6.1762  0.0134   162316   0.020071   0.0   7.3 343

where:
   yr = year
   mo = month
   da = day of month
   hhmm = time (UTC/GMT)
   pos = instrument position on concrete slab
   vis = visibility (m)
   flash  = flash count, measured with LED on
   dark = dark count, measured with LED off
   diff = count difference, flash-dark  
   extCo = Extinction coefficient (1/km)
   urng = under-range QC parameter 
   orng = over-range QC parameter 
   pts = points averaged in 6 minutes