User Manual LT80 LED Light Meter Introduction Congratulations on your purchase of the Triplett LT80 LED Light Meter that measures light intensity from white LED light sources. The LT80 can also measure light from fluorescent, metal halide, high‐ pressure sodium, and incandescent sources, for reference only (unspecified accuracy). The LT80 can measure light up to 40,000 Fc (400,000 Lux).
Safety Do not operate the meter in environments where the following are present: explosive gases (or materials), combustible gases (or materials), steam, or dust. Please replace the battery immediately when the low battery symbol appears on the LCD. Do not touch the meter’s circuit board for any reason; static electricity or contamination could damage the sensitive components. This instrument was designed for pollution degree 2. Operation Altitude: Up to 2000m (7000’). Description 1.
Operation Power ON/OFF Long press the Power button to power the meter. To power the meter OFF, short press the Power button. Taking Measurements 1. Switch the meter ON and remove the sensor’s protective cover to expose the light sensor dome. The display should switch ON; if not, check that batteries are installed and fresh. 2. The meter measures the intensity of the light (illuminance) that strikes the sensor dome in foot‐candles and Lux units (1 fc = 10.76 lux), displaying this measured value on its LCD.
MAX/AVG/MIN Button The meter can record the maximum, minimum, and average readings as described below: Short press the “MAX/MIN” button and the meter will begin to track the maximum/average/minimum measurements; the “MAX” icon will display at the top of the LCD window indicating that the meter is now showing the maximum reading. The reading will not change until a higher reading is registered.
3. If the protective cap is not covering the sensor when the Zero calibration is started the LCD display will read CAP. In this case, please cover the sensor with the cap and restart this procedure. Measurement Tips For maximum accuracy allow the light being measured to fall directly on the sensor as perpendicular as possible with a minimal angle of incidence. When the meter is not in use, please keep the protective cap in place over the light sensor. This will prolong the life of the sensor.
Specifications Display 9999 count, maximum display 9999 Sensor Silicon photodiode and filter 999.9,9999, 99990,400,000 Lux 99.99,999.9,9999,40,000 Footcandles 0.1,1, 10,100 Lux 0.01,0.1,1,10 Footcandles Measuring Range Resolution ±3% ±3Lux(0~500Lux), ±3%(up 501 Lux) Accuracy (Calibrated to standard incandescent lamp 2856°K) 8% other visible light source Angle deviation from cosine characteristics 30° ±2% 60 ° ±6% 80 ° ±25% Power Supply 2 batteries 1.
Relative Spectral Sensitivity The deviation from the comparative standards for luminosity is determined by JIS standard C 1609-1993. Peak sensitivity wavelength: 550 nm . Typ. Ta=23℃ 100 90 RELATIVE SENSITIVITY (%) 80 70 V(λ)＊ 60 50 40 30 20 TM-721 10 0 380 440 500 560 620 680 740 WAVELENGTH (nm) Typical Light Levels (1 Fc = 10.
200‐750 20‐75 Conference, Reception Room 750‐1,500 75‐150 Clerical Work 1,500‐2,000 150‐2000 Typing, Drafting Store 75‐150 7‐15 Indoors 150‐200 15‐20 Corridor/Stairs 200‐300 20‐30 Reception 300‐500 30‐50 Display Stand 500‐750 50‐75 Elevator 750‐1,500 75‐150 Show Window, Packing Table 1,500‐3,000 150‐300 Storefront, Show Window 300‐750 750‐1,500 30‐75 75‐100 100‐150 150‐200 200‐750 750‐1,500 30‐75 Cooking Room, Dining Table 75‐150 Show Window Hospital Emergency Stairs Stairs Sick Room, Warehouse 15‐20
