site TOOLIK-SNOW public variables downloaded at Fri Nov 20 09:05:21 2009 AKDT
' example perl code to get the epoch seconds at start of year:
' $ perl -MTime::Local -e 'print timelocal(0,0,0,1,0,shift),"\n"' 2009
'' control port allocations:
'' measured thermistor bridge resistor values, kOhms:
'' derived an empirical relation from dataset from -40 to 0C:
' Steinhart & Hart coeff. for YSI 44004 thermistors, 2252 Ohms @ 25C:
'' first 7 public variables appear on first keypad screen:
'' Geonor variables; prefix gnr: geonor vibrating wire
'' misc variables:
'' alternate sr50 3-echo mode for both sensors:
'' AT thermistors reference R, measured R:
'' corrections, so select an appropriate sensor here:
'' daily tables:
'' hourly tables:
'' fixed-size tables, wrap after 5 days:
'' table size calculated as: days*minutes_per_day/interval_minutes
  '' read and process 3 AT thermistors wired to SE14,15,16:
  '' temperature-corrected distance, negative value:
  '' offset by assumed sensor height for resultant snowdepth [cm]:
  '' reset error indicators:
  '' update filter values if all is ok:
      ''   applied to the time constants:
      ''   arbitrary function used: 1=best, lower=poorer
      '' start with weighted 1 hour time constant:
  '' special case: radio turns on at noon regardless of V limits
  '' turn radio on and read settings from constants:
  '' measured values of ATB reference resistors:
  '' copy initial sensor heights into variables:
  '' seed west sr50 filter values with initial reading:
  '' seed east sr50 filter values with initial reading:
  '' turn on the power relay for this transducer:
    '' tc weighting factor: 1 when WS=0, 5 when WS=15 (arbitrary relation)
    '' produce for each xdcr: frequency, mm water in bucket, mm change this scan
    '' clear precip mm event variables:
    '' using this relation with calibration constants:
    ' transducer vw3 has a power relay, so skip if not turned on:
    '' result message includes command (T) and several fixed-width fields:
        '' check time: subtract tps time (unix epoch) from logger time
  '' at startup:
    '' read AT thermistors and Geonor orifice RTD:
    '' read tps sensors:
    '' calculate temperature correction factor:
      '' read each SR50 with 3-echo mode, no multiplier or offset:
      '' apply tempcorrfactor and convert distances to negative cm:
    '' hourly:
    '' 5-day:
    '' event:
    '' daily:
    '' run & log experimental high-speed sampling of geonor xdcrs: