Extech Instruments LT250W User manual

User Manual
LT250W Light Meter
Bluetooth®Connectivity with the ExView®Mobile App

Table of contents
1 Introduction........................................................................1
2 Safety ................................................................................2
3 FCC Compliance .................................................................3
4 Product Description ............................................................4
4.1 Meter Description .......................................................4
4.2 Function Buttons ........................................................4
4.3 Display Symbols.........................................................5
5 Operation...........................................................................6
5.1 Powering the Meter ..................................................... 6
5.2 Auto Power Off (APO)..................................................6
5.3 Taking Measurements .................................................6
5.4 Changing Measurement Units ....................................... 7
5.5 Data Hold Function .....................................................7
5.6 LCD Backlight............................................................ 7
5.7 MAX/MIN Readings .................................................... 7
5.8 Bluetooth Operation ....................................................7
6 Maintenance.......................................................................9
6.1 General Cleaning .......................................................9
6.2 Battery Replacement...................................................9
7 Specifications................................................................... 10
7.1 General Specifications............................................... 10
7.2 Measurement Specifications ....................................... 10
7.3 Environmental Specifications ...................................... 10
7.4 Connectivity Specifications ......................................... 11
8 Two-year Warranty............................................................. 12
8.1 Calibration and Repair Services................................... 12
8.2 Contact Customer Support ......................................... 12
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Introduction
1
Thank you for selecting the Extech LT250W Light Meter. This meter measures
illuminance and displays it in Lux or foot candle units on the backlit LCD. Light
is captured by the built-in domed photo-cell, situated at the top of the meter.
The meter includes Bluetooth connectivity, MAX/MIN memory, selectable unit
of measure, auto power off, data hold, backlit LCD, and tripod mount.
Using the Extech ExView mobile app, you can pair your smart devices with
the meter using Bluetooth. The app and the W Series meters were developed
together for seamless integration. Download the free app from the App Store
(iOS®) or from Google Play (Android™).
This quality instrument is designed to provide years of reliable service, high
accuracy and simple operation. Please visit the Extech website for additional
information and world-class support.
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Safety
2
Please read all safety information before using this device
CAUTION
• Check for damage to the device’s housing, sensor, display, and battery compartment
before use. If obvious damage or abnormalities are noticed, please discontinue use
and return the device for service.
• Do not attempt to open the meter housing or access the sensor module. There are no
user-serviceable components in this device.
• Replace the batteries immediately after the low battery symbol appears. If the device is
to be stored for a period of months, please remove the batteries and store separately.
• Do not store the device in high temperature or humidity environments, in flammable or
combustible areas, or where a strong electromagnetic field is present.
• This device is CE certified.
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FCC Compliance
3
This equipment has been tested and found to comply with the limits for a
Class B digital device, pursuant to part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with the instruc-
tions, may cause harmful interference to radio communications. However,
there is no guarantee that interference will not occur in a particular installation.
If this equipment does cause harmful interference to radio or television recep-
tion, which can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one or more of the following
measures:
1. Reorient or relocate the receiving antenna.
2. Increase the separation between the equipment and receiver.
3. Connect the equipment into an outlet on a circuit different from that to
which the receiver is connected.
4. Consult the dealer or an experienced radio/TV technician for help.
WARNING
Changes or modifications not expressly approved by the party responsible for compliance
could void the user's authority to operate the equipment.
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Product Description
4
4.1 Meter Description
1. Light sensor
2. Backlit LCD (detailed below)
3. Function buttons (detailed below)
4. Tripod mount
5. Battery compartment
4.2 Function Buttons
Power / Bluetooth button
Long press to switch the device on. Short press to switch off.
With meter powered, long press to switch Bluetooth on/off.
Short press to switch the meter off directly from the Bluetooth mode.
MAX/MIN button
Short press to cycle through MAX/MIN readings. MAX/MIN memories
are cleared each time meter power is cycled.
Data Hold / Backlight button
Short press to freeze/unfreeze the displayed reading. HOLD will display
when data hold is active.
Long press to switch the LCD backlight on/off.
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Product Description
4
Unit of Measure button
Short press to toggle Lux and foot candle (fc) units. Lux is the standard
measurement unit, Foot candle readings are calculated.
APO ON/OFF With the meter on, long press the power and Hbuttons to switch APO
on/off. The APO symbol is displayed when APO is enabled. APO is
reset each time the meter power is cycled.
4.3 Display Symbols
1. Bluetooth active
2. Illuminance measurement
3. Maximum and Minimum reading modes
4. Data Hold
5. Low battery symbol
6. Unit of measure symbols
7. x10 and x100 indicators (multiply reading)
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Operation
5
5.1 Powering the Meter
The meter operates on three (3) 1.5 V (AAA) batteries, installed in the rear
compartment.
Long press the power button to switch the meter on. Short press the power
button to switch the meter off. If the meter does not switch on, check the bat-
teries for proper orientation.
When the low battery symbol appears on the display, replace the batteries
immediately to ensure accurate readings.
5.2 Auto Power Off (APO)
The meter switches off automatically five (5) minutes after the last button
press.
The default mode for APO is ON (the APO symbol indicates that APO is
enabled).
To switch the APO function off, with the meter switched on, long press the
power and data hold (H) buttons. The APO symbol will switch off, indicating
that the function is disabled. APO is reset each time the meter’s power is
cycled.
Repeat this process to switch APO back on manually.
5.3 Taking Measurements
1. Long press the power button to switch the meter on.
2. Hold the meter in hand, set it face-up on a table or desk, or mount it on a
tripod in the area under test.
3. For best results, allow the light to fully encompass the sensor dome. Also,
reduce the ‘angle of incidence’ as much as possible (angle at which the
light strikes the dome).
4. Read the illuminance reading on the LCD. If the x10 or x100 display ap-
pears, multiply the displayed reading by 10 or 100 to obtain the actual
measurement.
5. If the measurement is out of range, OL will appear on the display in place
of a typical reading.
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Operation
5
CAUTION
Do not touch or otherwise obstruct the sensor.
Do not allow liquids to come in contact with the sensor.
5.4 Changing Measurement Units
Short press the LUX / FC button to toggle the displayed unit of measure (Lux
or foot candles).
5.5 Data Hold Function
Short press the Data Hold (H) button to freeze/unfreeze the displayed read-
ings. While Data Hold is active, HOLD will appear on the LCD.
5.6 LCD Backlight
Long press the backlight button to switch the display backlight on or off.
Excessive use of the backlight will shorten battery life.
5.7 MAX/MIN Readings
When the device is switched on, it begins tracking the highest (MAX) and low-
est (MIN) readings.
Short press the MAX/MIN button to step through the MAX/MIN memories.
MAX will show when the Maximum reading is displayed and MIN will show
when the Minimum reading is displayed. The memories are cleared each time
the meter power is cycled.
Press the MAX/MIN button again to exit this mode (MAX and MIN symbols
switch off when you exit).
5.8 Bluetooth Operation
Long press the Bluetooth button with the meter on, to switch Bluetooth on
or off. This communication symbol is shown when Bluetooth is on.
The Bluetooth utility allows you to remotely monitor readings on an iOS or An-
droid smart device using the Extech ExView mobile app designed for use with
this meter.
Download the ExView mobile app from the App Store for iOS devices or from
Google Play for Android devices. Instructions for mobile app use are available
from the ExView product page on the Extech website (link below).
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Operation
5
http://www.extech.com
Switch APO off when using Bluetooth by pressing and holding the power
and Hbuttons for 2 seconds (the APO symbol will switch off). This will pre-
vent the meter from automatically switching off while you are logging data or
monitoring readings in real time on your smart device.
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