Extech LT40 LED Light Meter User Manual

1. Introduction

The Extech LT40 is a compact and accurate LED Light Meter designed for measuring light levels from white LED light sources, as well as standard light sources. This device is essential for professionals needing to monitor and optimize environmental light levels in various settings such as offices, warehouses, public lots, hallways, and stairways. It provides measurements in both Lux and Foot-Candle (FC) units.

Figure 1: Extech LT40 LED Light Meter

2. Safety Information

Please read all safety information before operating the Extech LT40 LED Light Meter. Failure to follow these instructions may result in damage to the device or personal injury.

• Do not expose the meter to extreme temperatures or high humidity.
• Avoid dropping the meter or subjecting it to severe impact.
• Keep the sensor clean and free from obstructions to ensure accurate readings.
• Do not attempt to open the meter casing; there are no user-serviceable parts inside.
• Dispose of batteries according to local regulations.

3. Product Overview

3.1 Key Features

• USB interface for easy setup and data download.
• Selectable data sampling rates from 1 second to 24 hours.
• LCD displays current readings, min/max, and alarm status.
• Includes Windows 2000, XP, and Vista compatible analysis software.
• Measures white LED and standard lighting in Lux or Foot-Candle (FC) units.
• Features cosine and color corrected sensor for accurate measurements.

3.2 Components

The Extech LT40 LED Light Meter consists of the following main components:

• Light Sensor: Located at the top of the meter, responsible for detecting light.
• LCD Display: Shows measurement readings, units, and status indicators.
• Control Buttons:
  • Power Button: Turns the meter on/off.
  • LUX/FC Button: Toggles between Lux and Foot-Candle units.
  • CAL/ZERO Button: Used for calibration and zeroing the sensor.
  • MAX/MIN Button: Displays maximum and minimum recorded readings.
  • HOLD Button: Freezes the current reading on the display.
• Battery Compartment: Located on the back of the unit.
• USB Port: For connecting to a computer for data transfer.

4. Setup

4.1 Battery Installation

1. Locate the battery compartment on the back of the LT40 meter.
2. Slide the battery cover open.
3. Insert two (2) AAA batteries, ensuring correct polarity (+/-). The batteries are included with the meter.
4. Close the battery cover securely.

4.2 Software Installation

The LT40 includes analysis software compatible with Windows 2000, XP, and Vista. Refer to the software's installation guide for detailed instructions on installing and configuring the software for data download and analysis.

5. Operating Instructions

5.1 Taking a Measurement

1. Press the Power button to turn on the meter.
2. Select the desired unit (Lux or FC) by pressing the LUX/FC button.
3. Place the light sensor in the area where you wish to measure the light level. Ensure the sensor is facing the light source directly for accurate readings.
4. Read the light level displayed on the LCD.

Figure 2: Measuring light levels with the Extech LT40

5.2 Zeroing the Meter

To ensure accuracy, it is recommended to zero the meter before taking measurements, especially in low light conditions.

1. Place the protective cap over the light sensor to block all light.
2. Press the CAL/ZERO button. The display should show '0' or a very low value.
3. Remove the cap to begin measurements.

5.3 Using MAX/MIN and HOLD Functions

• MAX/MIN: Press the MAX/MIN button to cycle through the maximum, minimum, and current readings. This is useful for monitoring light level fluctuations over time.
• HOLD: Press the HOLD button to freeze the current reading on the display. Press it again to release the hold and resume live measurements.

5.4 Data Logging and Transfer

The LT40 supports data logging with selectable sampling rates. Connect the meter to a computer using the USB interface and utilize the included software to configure logging parameters, download recorded data, and perform analysis.

6. Maintenance

Proper maintenance ensures the longevity and accuracy of your Extech LT40 LED Light Meter.

• Cleaning: Wipe the meter clean with a dry, soft cloth. Do not use abrasive cleaners or solvents. Ensure the light sensor is free of dust and debris.
• Storage: When not in use for extended periods, remove the batteries to prevent leakage. Store the meter in a cool, dry place, away from direct sunlight and extreme temperatures.
• Calibration: While the meter is designed for high accuracy, periodic professional calibration may be required depending on your application and industry standards. Refer to Extech's official support for calibration services.

7. Troubleshooting

8. Specifications

9. Warranty and Support

Extech Instruments is a trusted brand by professionals, sold in over 100 countries for over 45 years.

• Manufacturer: Extech
• Warranty: Refer to the manufacturer's official website or the documentation included with your product for specific warranty details and terms.
• User Manual (PDF): For a downloadable PDF version of the user manual, please visit the official Extech website or access it via this link: Extech LT40 User Manual PDF.
• Online Support: For additional support, FAQs, and product information, visit the official Extech store: Extech Store on Amazon.