Triplett LT75 User manual

User Manual
LT75
Lux/Fc Light Meter
Introduction
Thank you for selecting the Triplett LT75 LUX/FC Light Meter. The LT75
measures light from fluorescent, metal halide, high-pressure sodium and
incandescent sources in lux and foot-candles.

Safety
Please read the entire User Manual before operating this device. Use the
meter only as specified and do not attempt to service or open the meter
housing.
Do not use the meter in the presence of explosive gas or vapor
Do not expose the meter to extremes in temperature or to high humidity
Please dispose of batteries and meter responsibly and in accordance
with all applicable laws and regulations
Do not allow children to handle the meter or the protective cover
Meter and LCD Description
METER DESCRIPTION
1. Light Sensor (protective sensor cover not shown)
2. LCD
3. LUX-FC button
4. Power Button
5. CAL-ZERO
button
6. Data Hold button
7. MAX-MIN Record button
Note: Battery compartment
and Tripod mount on rear
of meter

LCD DESCRIPTION
1. Battery status
2. Auto Power OFF (APO)
3. Data Hold
4. Maximum reading
5. Average reading
6. Minimum reading
7. Measurement
8. Units of measure
9. Calibration (ZERO)
1. Function Indicator
Operation
Meter Power
Power the meter by long pressing the button. The meter will
begin displaying light intensity readings. If the LCD does not switch
on, check the batteries located in the rear battery compartment.
Short press power button to turn OFF the meter.
Zero Calibrate the Sensor
1. Place the protective cover over the sensor and press the
button to power on the meter.
2. If the display does not read ‘0.0’ short press the button.
3. The CAL icon will appear in the secondary display.
4. The CAL icon will switch OFF when the calibration has been
completed.

5. If the protective cap is not covering the sensor when the
button is pressed, the LCD display will read “CAP”. In this case,
please cover the sensor with the cap and restart this procedure.
6. It is recommended that the meter be switched off and then on
again when repeating the zero calibration function.
Taking Measurements
Remove the sensor cover and aim the sensor toward the light source.
View the measurement on the meter’s display.
Selecting the Unit of Measure
Press the button to toggle the units between Lux and Foot-
candles. The units will indicate in the display.
Data Hold
Short press the button to freeze or unfreeze a reading on the
display.
MAX/MIN Button
The meter records the maximum, minimum, and average readings as
described below:
1. Short press the button and the meter will begin tracking
the maximum, average, and minimum measurements. The MAX
icon will display at the top of the LCD indicating the meter is
now showing the maximum reading. The reading will not
change until a higher reading is registered.
2. Short press the button again to switch from MAX to AVG,
where the meter will show the average measurement value. The
AVG icon will display in the LCD indicating the meter is now
showing the average reading.
3. Short press the button again to change the mode from AVG
to MIN, where the meter will show the minimum measurement
value. The MIN icon will display in the LCD indicating the meter is
now showing the minimum reading.

4. Short press the button to step through MAX-AVG-MIN
readings.
5. To exit this mode, long press the button. The
MAX/AVG/MIN display icons will switch off, and the meter will
return to normal operating mode.
Auto Power OFF (APO)
In order to conserve battery life, the meter will automatically shut
off after approximately 12 minutes of inactivity. The icon will
appear in the display when APO is enabled.
To turn APO on or off, with the meter powered ON, long press the
button. The icon will appear in the upper LCD when APO is
enabled and disappear when APO is disabled.
Measurement Considerations and User 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 over the
light sensor. This will prolong the life of the sensor.
When the meter is to be stored for long periods, please remove the
batteries and store them separately. Batteries can leak and cause
damage to the meter’s components.
Avoid areas of high temperature and humidity when using this
instrument.

Maintenance
Battery Replacement
1. Power OFF the meter.
2. Press the button that secures the battery compartment at
the back of the meter while sliding the battery compartment
cover off in a downward motion.
3. Replace the two (2) ‘AAA’ batteries observing correct polarity.
4. Re-assemble the meter before use.
Safety: Please dispose of batteries responsibly; never dispose of
batteries in a fire, batteries may explode or leak. If the meter is not to
be used for 60 days or more, remove the battery and store separately.
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.

Specifications
Display
9999 count LCD
Sampling rate 2.5 times per second
Light sensor
Silicone photodiode with cosine correction
filter
Measurement Units
LUX and FC (Foot candles)
Lighting source
types
Fluorescent, metal halide, high-pressure
sodium, and
incandescent
Input Overload
Display
‘OL’
Tripod mount
On back of meter
Power
2 x 1.5V AAA batteries
Low battery indicator included
Automatic power off
After approx. 12 minutes of inactivity
Operating
Temp/Humidity
5°C to 40°C (40°F to 104°F); <80%RH Max
Operating Altitude
2000 meters (7000ft) maximum
Storage
Temp/Humidity
-10°C to 60°C (14°F to 140°F); <70%RH Max
Dimensions/Weight
133 x 48 x 23mm (5.3 x 1.9 x 0.9”) /250g
(8.8oz)
Safety
For indoor use only. EMC: EN61326-1 (2006),
IEC 61000-
4-2 (2008, IEC 61000-4-3 (2006) + (2007);
Pollution
Degree 2.

Typical Light Levels (1 Fc = 10.76 Lux)
Lux
Foot
Lux
Foot
Candles
Candles
Factories
Home
20-75
2-7
Emergency Stairs,
100-150
10-15
Washing
Warehouse
75-150
7-15
Exit/Entrance
Passages
150-200
15-20
Recreational Activities
150-300
15-30
Packing Work
200-300
20-30
Drawing Room, Table
300-750
30-75
Visual Work:
Production
300-500
30-50
Makeup
Line
750-1,500
75-150
Typesetting:
Inspection
500-1,500
50-150
Reading, Study
Work
1,500-
3,000
150-300
Electronic Assembly,
1,000-
2,000
100-200
Sewing
Drafting
Office
Restaurant
75-100
7-10
Indoor Emergency
Stairs
75-150
7-15
Corridor Stairs
100-200
10-20
Corridor Stairs
150-300
15-30
Entrance,
Wash Room
200-750
20-75
Conference,
300-750
30-75
Cooking Room, Dining
Table
Reception Room
750-1,500
75-150
Clerical Work
750-1,500
75-150
Show Window
1,500-
2,000
150-
2000
Typing, Drafting
Store
Hospital
75-150
7-15
Indoors
30-75
3-7
Emergency Stairs
150-200
15-20
Corridor/Stairs
75-100
7-10
Stairs
200-300
20-30
Reception
100-150
10-15
Sick Room, Warehouse
300-500
30-50
Display Stand
150-200
15-20
Waiting Room
500-750
50-75
Elevator
200-750
20-75
Medical Exam Room
750-1,500
75-150
Show Window,
750-1,500
75-150
Operating Room
Packing Table
1,500-
3,000
150-300
Storefront, Show
Window
5,000-
10,000
500-
1000
Eye Inspection

Spectral Sensitivity
Peak sensitivity wavelength: 550nm; Deviation from comparative
luminosity standard: JIS standard C1609-1993.
Warranty
Triplett / Jewell Instruments extends the following warranty to the original purchaser of
these goods for use. Triplett warrants to the original purchaser for use that the products
sold by it will be free from defects in workmanship and material for a period of (1) one
year from the date of purchase. This warranty does not apply to any of our products
which have been repaired or altered by unauthorized persons in any way or purchased
from unauthorized distributors so as, in our sole judgment, to injure their stability or
reliability, or which have been subject to misuse, abuse, misapplication, negligence,
accident or which have had the serial numbers altered, defaced, or removed.
Accessories, including batteries are not covered by this warranty
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