TES-1333R RS-232 Interface Datalogging Solar Power Meter FEATURES Wide spectral range. Excellent long term stability. Cosine corrected. Automatic transmission measurements. Select either power or transmission. Solar energy power or transmission. Current time setting function. User calibration factor setting function. End-mount light sensor. Select either W/m2 or Btu / (ft2*h) unitsData Hold / MAX / AVG modes. Data Memory and Read function. (99 sets.) RS232 interface to PC Meteorology agriculture solar radiation measurement solar power research physics and optical laboratories solar transmission measurement identify high performance windows                             Display        3-1/2 digits.Max.indication1999                    Range        2000W/m 2 634Btu/(ft 2 * h)                    Resolution        1W/m21Btu/(ft2*h)                    Spectral response        400-1100nm                    Accuracy        Typically within ± 10W/m2[ ±3 Btu / (ft2*h) ] or ±5% , whichever is greater in sunlight; Additional temperature induced error ±0.38W/m2 / [ ±0.12 Btu / (ft2*h)/ ] from 25                    Angular accuracy        Cosine corrected <5% for angles <60 °                    Drift        <±2% / per year                    Calibration        User recalibration available                    Over-input        Display shows" "                    Sampling Time        Approx. 0.4 second                    Manu data memory and read        99 sets                    Auto data memory        32000 sets                    Battery        4pcs size AAA                    Battery Life        Approx.