Turf-Tec Light-DLI-W User manual

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Daylight Indicator - Light Meter
Light-DLI-W
The Daylight Indicator - Light Meter is a
simple and easy step in measuring the light
intensity levels affecting your turf or crops
and can be used outdoors, on golf greens,
stadiums or inside a greenhouse or other
structure. This water-resistant unit will
compare light level intensities within or
outside your greenhouse. Simply place it on
the area to be tested and 24 hours later, it
will display your Daily Light Integral (DLI).
With a push of a button, the Daylight
Indicator records light intensity for a 24-hour period and then calculates the Daily
Light Integral (DLI). Real-time intensity levels are shown every 4 seconds in µmol
⚫m-2⚫s-1 (or footcandles). Battery included.
Specifications:
•Plastic Spike
• Button on the face
• Uses three A76/LR44/L1154
batteries (included)
• Simple, one button operation
• An affordable, first step in measuring light
• Measure PAR light (Photosynthetically Active Radiation)
(the range between 400 and 700 nm)
• With the push of a button, the meter runs for 24
hours and calculates your Daily Light Integral (DLI)
• Real-time intensity levels are shown every 4
seconds in μmol⚫m-2⚫s-1 (or footcandles)
• Approximate battery life: 100 DLI calculations

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Daylight Indicator
Quick Start Guide
1. Place unit in desired location
The unit needs to be placed in the location you require measurement. Once the
unit is in the desired location you can compare the amount of light.
2. Once in place the unit will start measuring
Press the button on the shoulder of the Daylight
Indicator. The LEDs will light upward and will blink
every 4 seconds to show the current light intensity.
Read the value from the right side of the LEDs.
3. Wait 24 hours
The Daylight Indicator will sum the light
measurements for 24 hours and compute the Daily
Light Integral (DLI).
4. Read the Daily Light Integral (DLI)
After 24 hours the Daylight Indicator will blink every
second for the next hour to show the DLI value. Use
the numbers to the left of the LEDs. If the display is
dark, press the button to wake it and see the value
for 10 seconds.
5. Repeat with any and all areas requiring light measurements
Choose other areas and repeat the process for maximum
benefit.
Important
The Daylight Indicator does have a sharp spike so handle with care.
Do not store the Daylight Indicator upside-down.
Possible damage can occur from irrigation water that
can gather in the screw holes, enter the unit,
and damage the circuit board.

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Where to Measure?
Use a “Control”
Use the Daylight Indicator to measure the location of primary interest—on a greenhouse bench,
or on a shaded green or tee box at a golf course. Use can also use it as a “control” - let it receive
the maximum light, either outside your greenhouse, or in full sun, far from the trees.
In a Greenhouse
Place Daylight Indicator where you can compare light levels and DLI (Daily Light Integral) with
and without hanging plants and shades. Use pots with soil or media to hold the Daylight Indicator
upright. Place the Daylight Indicator outside to measure transmission loss through the structure.
Shaded Tees, Sports Stadiums and Greens
Use the Daylight Indicator to compare the light received by healthy and stressed areas of tees,
stadiums and greens. By placing unit in the stressed area, followed by a healthy area, and then
nearby with full sun, areas of destructive shade can be documented, and the minimum light level
necessary can be determined. In the Crop Canopy
To measure the incident light and/or DLI at, in, or below the crop canopy, secure the Daylight
Indicator at the proper location and height. For low plants, this can be as simple as inserting the
spike into the ground or into a container filled with soil or media. For taller crops, set a plastic or
metal pipe into the ground, and slip the Daylight Indicator spike into the top to hold it at the
desired height.

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Using the Daylight Indicator
Place the Daylight Indicator in the ground at the desired location for evaluating
the amount of available sunlight. In a greenhouse insert the meter into a container of
similar size (containing substrate only) to that of the crop being grown, so that the meter
receives the same amount of light at the same height as the growing crop. Ensure
that the face of the unit is generally parallel to the ground.
Light Gathering Mode
To turn On the Daylight Indicator, press the power button located on the face of the
device. When the power is applied, the four LEDs will illuminate sequentially from bottom
to top. Thereafter, one or more LEDs will flash every 4 seconds, indicating the amount of
light currently being received.
The Daylight Indicator measures the actual light intensity every 20 seconds, then displays that
value every 4 seconds until the next measurement is made.
*Please Note*
While the Daylight Indicator is gathering data, pressing the power button will turn off the
unit (the four LEDs will illuminate sequentially from top to bottom), and the measurement
process will be cancelled. Pressing the button again will start a new 24-hour
measurement period.
DLI Display Mode
After 24 hours of continuous operation, the device will stop accumulating light
measurements. One or more LEDs will flash every second for one hour to indicate the
Daily Light Integral (DLI) for that location. The device will shut itself off after displaying
the DLI value for one hour, but the DLI measurement will be retained in memory.
The last DLI value computed can be retrieved from memory by pressing the power
button to turn on the unit. The DLI value will flash every second for 10 seconds.
*Important*
After 10 seconds the Daylight Indicator value will be erased, and a new 24 hour
measurement period will begin. Pressing the button again before 10 seconds
has elapsed will turn the unit off and save the DLI value.

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Reading the Display
The Daylight Indicator - Light Meter has 4 LEDs that are used to indicate different levels
of light - both intensity and Daily Light Integral (DLI). The LEDs flash once every four
seconds during the Light Gathering Period. Numbers to the left of the LEDs indicate the
current light intensity in μmol⚫m-2⚫s-1 (micromoles). A sunlight approximation of foot
candles can be obtained by multiplying the value by 5. Numbers to the right of the LEDs
are used to display the DLI value in mol⚫m-2⚫d-1. The LEDs flash once per second.
One LED
When one LED is flashing, read the number next to it. The light level will be at least that
number. In the image to the right:
During the Light Gathering period, by reading the left numbers, the light
intensity would be in the range 1000- 1499 μmol⚫m-2⚫s-1 (“1000” is lit,
and the top of the range is less than
1500, the next number up). In DLI Display mode, by reading to the right,
the DLI value would be in the range 20-29 mol⚫m-2⚫d-1
Two LEDs
If the light level is between two LEDs, then
both flash. In this case, use the number between them.
For the image to the left:
During the Light Gathering period, by reading the left numbers,
the light intensity would be in the range 750-999 μmol⚫m-2⚫s-1
(“750” is between the two lit LEDs, and the top of the range is
less than 1000, the next number up).
In DLI Display mode, by reading to the right, the DLI value
would be in the range 15-19 mol⚫m-2⚫d-1
Four LEDs
Under the highest light levels, all four LEDs flash. The numbers at the top of the display
(1500+, 30+) provide the “at least” values for these light levels.

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Light Intensity
The light that drives photosynthesis in plants is Photosynthetically Active Radiation, or
PAR light. This is also referred to as Quantum light, because it is measured in units of
moles striking an area over time. Though PAR light ranges from 400 to 700nm, the
region brightest to human eyes is the area of least effect on plants.
Light meters measure light intensity –the instantaneous amount of light delivered to
an area. During the 24-hour Light Gathering period, the Daylight Indicator functions as a
light meter.

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Cumulative Light (DLI)
If photons were raindrops, light meters would show the intensity of a rainstorm. A five-
minute rainstorm may look impressive, but often provides less water than an all-day
drizzle. As cumulative rainfall is measured with a rain gauge, the cumulative quantity of
light is measured using the Daylight Indicator, or a light sensor, with a data logger. The
daily total of Quantum light is called the Daily Light Integral, or DLI, and is measured in
units of mol⚫m-2⚫d-1 (commonly, moles/day). DLI quantifies the light available to plants
to perform photosynthesis. On a sunny winter day in the middle latitudes, a plant
receives about 9 moles/day. If it is cloudy, the DLI drops to 3 moles/day. In the summer,
the DLI for a sunny day is about 26 moles/day and 12 moles/day for a cloudy day. Each
type of plant has a different DLI range for optimal growth. DLI is directly correlated with
plant quality, and a minimum amount of light is required for healthy plants.
Effect of Light Intensity on Plant Growth and Quality
Relative
Light
Level
Daily Light
Integral (DLI)
mol⚫m-2⚫d-1
Light intensity
at Noon
μmol⚫m-2⚫s-1
Generalized Plant
Growth Response
Very Low
2 to 5
100 to 200
Poor quality
Low
5 to 10
200 to 400
Minimum
acceptable quality
Medium
10 to 20
400 to 800
Good quality
High
20 to 30
800 to 1200
Excellent quality
Very High
30 to 60
1200 to 2000
Excellent quality
Table 1. Generalized plant responses to different light levels. Please note that
it is not possible to convert a single light intensity reading to DLI. Additionally,
temperature is an important factor of plant growth and quality (table adapted
from Hamrick, Debbie ed. Ball Red Book. Batavia, IL: Ball Publishing.2003).

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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Replacing the Battery
The Daylight Indicator uses three cell
batteries A76/LR44/AG13/L1154. To change the battery:
1. Remove the three screws from the underside of the unit.
2. Lift off and turn over the top of the Daylight Indicator.
3. Remove the batteries.
4. Clean the battery contacts prior to installing batteries.
5. Batteries must be installed in the correct direction and polarity
(see image below).
6. Re-align the top of the Daylight Indicator with the base. Replace and
tighten the screws.
LIMITED WARRANTY OF TURF-TEC INTERNATIONAL PRODUCTS
Turfgrass Products Corporation - dba - Turf-Tec International ("Seller") warrants to the final purchaser, that all Turf-Tec International
tools will be free from defects in material or workmanship for a period of one year from date of purchase. SELLER'S SOLE
OBLIGATION AND YOUR EXCLUSIVE REMEDY under this Limited Warranty and, to the extent permitted by law, any warranty or
condition implied by law, shall be the repair or replacement of parts, without charge, which are defective in material or workmanship and
which have not been misused, carelessly handled, or improperly repaired by persons other than Turf-Tec International. To make a claim
under this Limited Warranty, you must return the complete tool, transportation prepaid, to Turf-Tec International after contacting Turf-
Tec International and receiving a return authorization number. Please include a dated proof of purchase with your tool.
ANY IMPLIED WARRANTIES SHALL BE LIMITED IN DURATION TO ONE YEAR FROM DATE OF PURCHASE. IN NO
EVENT SHALL SELLER BE LIABLE FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING BUT NOT
LIMITED TO LIABILITY FOR LOSS OF PROFITS) ARISING FROM THE SALE OR USE OF THIS PRODUCT.
Hold Harmless Agreement
The seller shall protect, defend, indemnify and hold the purchaser and their respective assigns and their attorneys, accountants, employees,
officers and directors harmless from and against all losses, costs, liabilities, claims, damages and expenses of every kind and character, as

Turf-Tec International Daylight Indicator –Light Meter - Copyright 2020
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incurred, resulting from or relating to or arising out of the inaccuracy of results, injury of user, injury of sports participant, turfgrass loss,
warranty, covenant or any agreement made by the seller in this agreement.