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USER MANUAL White LED Light Meter Model LT40 GlobalTestSupply www. .com Find Quality Products Online at: sales@GlobalTestSupply.com...
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Congratulations on your purchase of the Extech LT40 LED Light Meter that measures light intensity from white LED light sources. The LT40 can also measure light from fluorescent, metal halide, high‐ pressure sodium, and incandescent sources, for reference only (unspecified accuracy). The LT40 can measure light up to 40,000 Fc (400,000 Lux). This instrument is shipped fully tested and calibrated and, with proper use, will provide years of reliable service. Please visit our website ...
Battery compartment and tripod mount are located on rear of instrument Push‐Button Description Lux/Fc units selector Zero Calibration button Maximum/Average/Minimum memory button Data hold button 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. 3. Position the meter and light source so that the light strikes the sensor dome straight on (perpendicular) with as little an angle as possible. 4. The meter’s display can show a value up to 9999. However, for readings that represent measurements higher than this, the meter uses x10 or x100 feature. For example, to represent a measurement of 11,000 fc the meter will display 1100 with the x10 indicator. LT40-en-GB_V3.0 10/17 GlobalTestSupply www. .com Find Quality Products Online at: sales@GlobalTestSupply.com...
3. Press the “MAX/MIN” button again to change the mode from “AVG” to “MIN”, where the meter will show the minimum value measured. The “MIN” icon will be displayed. 4. Press the “MAX/MIN” button again to switch from “MIN” back to “MAX”. 5. To exit this mode, hold the “MAX/MIN” button for at least 2 seconds. The MAX/AVG/MIN icons should all be switched OFF when the unit returns to the normal operating mode. HOLD Button Press the HOLD button to freeze the current reading on the LCD. Press the HOLD button again to release the reading. In the Data Hold mode, HOLD is displayed on the LCD. Zero Calibration Procedure 1. Ensure that the protective cap is attached to the light sensor. 2. Power the meter and the LCD should display ‘0’. 3. Short press the “CAL ZERO” button to perform the zero adjustment (CAL will appear on the display). 4. The CAL display will switch off when the calibration has been completed. 5. 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. LT40-en-GB_V3.0 10/17 GlobalTestSupply www. .com Find Quality Products Online at: sales@GlobalTestSupply.com...
Cleaning and storage 1. The white plastic sensor dome should be cleaned with a damp cloth when necessary. Use only a mild soap if needed. Do not use solvents, abrasives, or harsh detergents to clean the dome. 2. Store the meter in an area with moderate temperature and relative humidity. Battery Replacement When the battery power decreases to a critical level, the low battery symbol “ ”will appear on the LCD. Replace the 2 x 1.5V AAA batteries located in the rear battery compartment. 1. Press and hold the battery compartment lock button (see diagram). 2. Slide the battery compartment cover off in the direction of the arrow. Install two (2) 1.5V ‘AAA’ batteries observing correct polarity and close the battery compartment. Ensure that the compartment cover is securely fastened before using the meter. Never dispose of used batteries or rechargeable batteries in household waste. As consumers, users are legally required to take used batteries to appropriate collection sites, the retail store where the batteries were purchased, or wherever batteries are sold. Disposal: Do not dispose of this instrument in household waste. The user is obligated to take end‐of‐life devices to a designated collection point for the disposal of electrical and electronic equipment. LT40-en-GB_V3.0 10/17 GlobalTestSupply www. .com Find Quality Products Online at: sales@GlobalTestSupply.com...
4 ‐digit LCD (maximum display: 9999) with low battery icon, measurement overload, and other function indicators Auto Range M eter automatically ranges the display Operating conditions Temperature: 5 to 40 C (41 to 104 F); Humidity: < 80% RH Storage conditions Temperature: ‐10 to 60 C (14 to 140 F); Humidity: < 70% RH Low battery indication appears on the LCD when battery voltage falls critically low LED Type White LED light Power supply 2 x 1.5V ‘AAA’ batteries Battery life Approximately 200 hours Auto Power OFF Meter switches OFF after 12 minutes of inactivity Dimensions 133 x 48 x 23 mm (5.2 x 1.9 x 0.9”) Weight 250 g. (8.8 oz.) including batteries LT40-en-GB_V3.0 10/17 GlobalTestSupply www. .com Find Quality Products Online at: sales@GlobalTestSupply.com...
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