USER GUIDE Pocket Light Meter Model LT10 Introduction Thank you for selecting the Extech Instruments Model LT10 Pocket Light Meter. The LT10 measures and displays light intensity in foot candle and Lux units using a precision photo‐diode sensor. This device is shipped fully tested and calibrated and, with proper use, will provide years of reliable service. Please visit our website (www.extech.com) to check for the latest version of this User Guide. The Extech Instruments brand, a wholly owned subsidiary of FLIR Systems, Inc., is ISO‐9001 certified. Safety Use CAUTION when operating this device. The light sensor is sensitive and should be handled with great care. Meter Description 1. Photo detector (Light Sensor): Sensor contains a long life silicon photo diode 2. MAX‐LUX/fc function button: Press button momentarily to view the maximum (MAX) reading. Press the button momentarily again to release the MAX display and return to the normal operating mode. Press and hold this button for at least 2 seconds to switch between LUX and fc (foot candle) units of measure. Note that 1fc = 10.76 LUX). 3. LCD Backlight Control Sensor: The meter switches the LCD backlight ON and OFF automatically based on environmental lighting conditions. 4. LCD display: 1999 count, backlit LCD with LUX, fc, MAX, and low battery icons. 5. Power button: Press to switch the unit ON or OFF. Note: Battery compartment and tripod mount are located on rear of instrument. 2 LT10‐en‐GB_v1.1 4/15 Operation Turn Power ON or OFF Press the button to turn power on or off. If the display does not switch on, check that a 9V battery is installed and is fresh. Selecting LUX or Foot candle (fc) units of measure Press and hold the MAX‐LUX/fc button for at least 2 seconds to switch between LUX and Fc units. Measurement Procedure 1. Switch the meter ON and position the light sensor to capture the light that is to be measured. 2. The display will indicate the light level in Fc or LUX units. 3. The meter automatically selects the correct range. If the ‘OL’ icon appears, the light measurement is out of range and cannot be measured accurately. 4. If the x10 or x100 indicator appears, multiply the displayed value by the corresponding multiplier to obtain the correct measurement value. Max Hold Momentarily press the MAX‐LUX/fc button to view the highest reading (MAX) encountered since the meter was last switched ON. Press the button again to return to the normal operating mode. To reset the MAX reading, switch the meter OFF and then ON again. LCD Backlight The meter automatically controls the LCD backlighting (ON and OFF) to match the available ambient lighting. 3 LT10‐en‐GB_v1.1 4/15 Battery Replacement When the battery power begins to fail, the low battery symbol will appear on the LCD. Replace the 9V battery by following these steps. 1. Open the rear battery compartment to access the battery 2. Replace the 9V battery, carefully securing the battery in the compartment 3. Securely fasten the compartment cover 4. Ensure that the compartment cover is securely fastened before using the meter All EU users are legally bound by the Battery Ordinance to return all used batteries to community collection points or wherever batteries / accumulators are sold. Disposal in household trash or refuse is prohibited. Disposal: Follow the valid legal stipulations in respect of the disposal of the device at the end of its lifecycle Battery Safety Reminders Please dispose of batteries responsibly; always observe local, state, and federal regulations with regard to battery disposal. Never dispose of batteries in a fire. Batteries may explode or leak. Never mix battery types or old and new batteries. Always install new batteries of the same type. 4 LT10‐en‐GB_v1.1 4/15 Specifications General Specifications Display 1999 Count Backlit LCD with LUX, fc, battery, and MAX indicators Display Polarity Automatically detects polarity; displays (‐) for negative polarity Over range indication LCD displays ‘OL’ Low Battery Indication Battery icon appears when battery voltage is below operating level Measurement rate 2.5 readings per second, nominal Measurement Repeatability ±2% MAX indication Displays highest reading Temperature coefficient ±0.1% per C Photo detector Silicon photo‐diode with spectral response filter Sensor Calibration Calibrated to standard incandescent lamp; color temperature 2856k Spectral response CIE photopic (CIE human eye response curve) o Power supply 9V battery Auto Power Off Meter automatically switches off after 17 minutes of inactivity o o Operating conditions Temperature: 0 to 40 C (32 to 104 F); Humidity: < 80% RH Storage conditions Temperature: ‐10 to 60 C (14 to 140 F); Humidity: < 80% RH o o Dimensions 157 (H) x 54 (W) x 34 (D) mm (6.2 x 2.1 x 1.3 ") Weight 170 g (6 oz.) Electrical Specifications Ranges and Resolution LUX 200.0, 2000, 20000, 40000 Foot candles (Fc) 20.0, 200.0, 2000, 4000 Accuracy ± (5% reading + 10 digits (<10000 LUX/fc) ± (10% reading + 10 digits (>10000 LUX/fc) Note that readings over 1999 will show the x10 or x100 multiplier. In these cases, multiply the displayed value by the multiplier to obtain the correct reading. Copyright © 2013‐2015 FLIR Systems, Inc. All rights reserved including the right of reproduction in whole or in part in any form www.extech.com 5 LT10‐en‐GB_v1.1 4/15 Appendices Typical Light Levels Lux Foot Candles Factories Emergency Stairs, Warehouse Exit/Entrance Passages Packing Work Visual Work: Production Line Typesetting: Inspection Work Electronic Assembly, Drafting Office 75-100 7-10 Indoor Emergency Stairs 100-200 10-20 Corridor Stairs 200-750 20-75 Conference, Reception Room 750-1,500 75-150 Clerical Work 1,500-2,000 150-2000 Typing, Drafting Stores 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 20-75 75-150 150-300 300-750 750-1,500 1,500-3,000 2-7 7-15 15-30 30-75 75-150 150-300 Lux Foot Candles 100-150 150-200 200-300 300-500 500-1,500 1,000-2,000 10-15 15-20 20-30 30-50 50-150 100-200 75-150 150-300 300-750 750-1,500 7-15 15-30 30-75 75-150 30-75 3-7 75-100 7-10 100-150 10-15 150-200 15-20 200-750 20-75 750-1,500 75-150 5,000-10,000 500-1000 Homes Washing Recreational Activities Drawing Room, Table Makeup Reading, Study Sewing Restaurant Corridor Stairs Entrance, Wash Room Cooking Room, Dining Table Show Window Hospitals Emergency Stairs Stairs Sick Room, Warehouse Waiting Room Medical Exam Room Operating Room Eye Inspection Spectral Sensitivity R e l a t i v e R e s p o n s e 1 0.8 0.6 0.4 0.2 0 400 450 500 550 600 650 700 Wavelength (nm) _____ - - - - - Light Meter Response CIE Response 6 LT10‐en‐GB_v1.1 4/15