General DLM112SD User manual

DLM112SD
USER’S MANUAL
LIGHT METER WITH
DATALOGGING D CARD
Please read this manual carefully and thoroughly before using this product.

TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Operating Instructions . . . . . . . . . . . . . . . . . . . . . 4 – 11
hat’s in the case . . . . . . . . . . . . . . . . . . . . 4 –5
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 –8
Normal Operation . . . . . . . . . . . . . . . . . . . . . 8 –9
Holding and Storing Measurements. . . . . . . . . . 9
Automatic vs. Manual Datalogging . . . . . . 9 – 10
Transferring Data from the SD Card
to a Computer . . . . . . . . . . . . . . . . . . . . . . 10 – 11
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Maintenance & Troubleshooting Tips . . . . . . . . . . . . 13
Optional Accessories. . . . . . . . . . . . . . . . . . . . . . . . . 13
arranty Information . . . . . . . . . . . . . . . . . . . . . . . . 13
Return for Repair Policy . . . . . . . . . . . . . . . . . . . . . . 14
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INTRODUCTION
Thank you for purchasing General Tools & Instruments’ DLM112SD UV Light Meter
with Datalogging SD Card. Please read this user’s manual carefully and thoroughly
before using the instrument.
The DLM112SD is a general-purpose handheld instrument suitable for measuring
the intensity of light in commercial, industrial and consumer settings. Applications
include photography, videography, construction, engineering and surveillance.
This light meter measures light intensity using either of two units: lux or foot-candles.
The lux is the standard international unit of illuminance, or how much luminous flux
is spread over a given area. One can think of luminous flux as a measure of the total
“amount” of visible light present, and illuminance as a measure of the intensity of
illumination on a surface. A given amount of light will illuminate a surface more dimly
if it is spread over a larger area, so illuminance is inversely proportional to area.
The standard international unit of luminous flux is the lumen, and one lux is equal to
one lumen/m2. For perspective on lux readings from the natural world, consider that
a moonless clear night sky has an illuminance of about 0.002 lux, while direct
sunlight has an illuminance of 30,000 to 130,000 lux.
The footcandle (or lumen per square foot) is a non-standard unit of illuminance.
Like the Btu, it is mainly in common use only in the U.S., particularly in construction-
related engineering and in building codes. Because lux and footcandles are different
units of the same quantity, it is perfectly valid to convert footcandles to lux and vice
versa. One footcandle (ft-cd) = 10.764 lux.
The DLM112SD has the performance and features needed to satisfy the most
demanding aspects of the above applications. It also has the ability to measure
surface temperature, using an optional Type K of Type thermocouple. A light probe
comes standard with the instrument.
Because it is microprocessor-based, the DLM112SD can make full use of the
portability, reliability and large storage capacities that SD memory cards offer.
Measurements of light intensity or temperature can be made automatically at any
of 11 sampling rates between one second and one hour. After time-stamping and
storing the measurements on an SD card plugged into the instrument (a process
called datalogging), the user can remove the card and transfer the measurements
to a laptop or desktop computer either directly or via a USB card reader.
The DLM112SD has a backlit 2-1/2 in. diagonal display and is powered by six “AA”
Alkaline batteries or an optional 9-VDC AC adapter.
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KEY FEATURE
• Includes light probe
• Measures light intensity within three automatically switched full-scale
ranges: 2,000 lux, 20,000 lux and 100,000 lux (200 ft-cd, 2,000 ft-cd and
10,000 ft-cd)
• Selectable lux or foot-candle unit
• Displays maximum and minimum readings
• Performs real-time automatic datalogging at sampling time settable from
1 second to 1 hour
• Also supports manual logging and changing of card storage location
• Accepts SD memory cards of up to 16 GB capacity
• Big (2.5 in. diagonal) front-panel green backlit LCD is easy to read
• Auto power off function
• Powered by six “AA” batteries or optional 9V AC/DC adapter
OPERATING IN TRUCTION
WHAT’S IN THE CASE
The DLM112SD comes fully assembled in a carrying case along with a light
probe with a protective cover, a 2 GB SD memory card and this user’s manual.
Optional accessories available from General Tools & Instruments include Type K
and Type J thermocouples and a 9VDC adapter for a 110V power supply. See
the Replacement Parts & Optional Accessories section of this manual for more
details.
Figure 1 shows all of the controls and indicators on the front, back, top, bottom
and right side of the DLM112SD. It also shows (at right) the main components
of the supplied light probe. Familiarize yourself with their positions and
functions before moving on to the setup procedure.
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1. The DLM112SD’s controls and indicators and other physical features
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TOP
RIGHT
SIDE
BACK
BOTTOM
FRONT
Fig. 1
1-1 Liquid-crystal display
1-2 POWER/ESC button
1-3 FUNC./ OLD/NEXT button
1-4 REC/ENTER button
1-5 SET ▼button
1-6 LOGGER ▲button
1-7 Socket for light probe
1-8 Socket for Type-K or -J
thermocouple temperature probe
1-9 SD card socket
1-10 RS232 output jack
1-11 RESET Button
1-12 Socket for 9VDC AC adapter
1-13 Battery compartment cover
1-14 Battery compartment cover
screws
1-15 Kickstand
1-16 Tripod attachment nut
1-17 Light probe plug
1-18 Light sensor housing
1-19 Light sensor
1-20 Light sensor cap

SETUP
1. Choose the power source. Before using the DLM112SD, be sure it is powered by
fresh batteries or an optional 9VDC AC adapter plugged into the bottom jack on its
right side (callout 1-12).
To remove the battery compartment cover, remove the two screws holding it in place
(callout 1-14). Then install six “AA” batteries in the correct orientation, using the
polarity marks on the inside of the compartment as a guide. Replace the cover by
replacing the two screws.
2. Install an SD card. To prepare for setup, also install the supplied 2 GB SD memory
card or another card with a capacity from 1 GB to 16 GB in the socket on the
bottom of the DLM112SD (callout 1-9). When installing the card, make sure its gold
contacts are facing front and push the card into the socket until you hear a click.
To remove the card, push it in until you hear a click and the card pops out.
Now power on the instrument by pressing the POWER/ESC button (callout 1-2) to
generate a short beep. (To power off the DLM112SD, press the POWER/ESC button
and hold it until the instrument responds with a long beep.)
When the DLM112SD powers on, a series of transient startup screens will briefly
appear. Once the display has stabilized, perform the following series of eight setup
steps in the order presented.
3. Set the date and time. Press the SET ▼button (callout 1-5) and hold it for at
least five seconds, until the word “dAtE” appears in the center of the display, along
with the flashing value “00.00.00” at the lower left, above “yy.mm.dd”.
(If you press buttons too slowly in setup mode, the screen will revert to the normal
display. To return to the setup sequence, press and hold the SET ▼button again. To
move ahead to the next field in the sequence or to the next parameter, press the
FUNC./ OLD/NEXT button (callout 1-3).)
First set the current year by pressing the SET ▼or LOGGER ▲button repeatedly
until the correct value appears above “yy”. Press the REC/ENTER button to store the
setting. The next screen that appears will have the value above “mm” flashing. Use
the SET ▼or LOGGER ▲button to navigate to the current month and press the
REC/ENTER button to store the setting. When the next screen flashes the value above
“dd”, again use the SET ▼or LOGGER ▲button to navigate to the current day and
press the REC/ENTER button to store the setting.
Once you have set the date, the display will prompt you to set the hour, minute and
second of the current time. Again use the SET ▼or LOGGER ▲buttons to navigate
to the correct values, and the REC/ENTER button to store the settings.
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4. Choose a decimal point or comma to represent the decimal division between
integers and fractions (for example, American-style 20.88 vs. European-style
20,88). Once you have finished setting the time, the display will show the word
“bASIC” above the phrase “dEC”. Press the SET ▼button to make “bASIC”
(American style) or “Euro” appear in the upper display, as desired. Press the
REC/ENTER button to store the selection.
5. Enable or disable auto power off. Once the format of decimal divisions has
been set and stored, the display will show the word “yES’ over the term “PoFF”.
Press the SET ▼button until the desired automatic power off management
scheme (“yES” for enable; “no” for disable) is displayed. Press the REC/ENTER
button to store the selection. If enabled, the power off function shuts off the
DLM112SD after a period of inactivity of ten minutes
6. Enable or disable the beeper. Once the desired power management function
has been set and stored, the display will show the word “yES” over the word
“bEEP”. Press the SET ▼button until the desired setting (“yES” or “no”) is
displayed, and then press the REC/ENTER button to store the selection.
7. Select the thermocouple type. Once the beeper has been enabled or disabled,
the display will show the word “Set” over the word “tYPE”. Press the SET ▼
button until the desired setting (“K” or “J”, for a Type K or Type J thermocouple)
appears on the right side of the display. Then press the REC/ENTER button to
store the selection.
8. Select the temperature unit. Once the thermocouple type has been set and
stored, the display will show the term “t-CF”. Press the SET ▼button until the
desired setting (“F” or “C”, for Fahrenheit or Celsius units) appears on the right
side of the display. Then press the REC/ENTER button to store the selection.
9. Set the datalogging sampling time. Once the temperature unit has been set
and stored, the display will show a value above the letters “SP-t”. Press the SET
▼button or the LOGGER ▲button to decrease or increase the value until the
desired sampling time appears above “SP-t”. The options are 0, 1, 2, 5, 10, 30,
60, 120, 300, 600, 1800 and 3600 seconds (0 seconds to 1 hour).
10. Format the SD card. Once the sampling time has been set and stored,
the word “no” or “yES” will be displayed over the term “Sd-F”. Press the SET ▼
button to make a selection.
Choose “yES” whenever a new SD card is being used, or when a used card is being
repurposed (from use with another SD card instrument or a camera, for example) and
all data on it is to be erased. Choose “no” to preserve any data on a card previously
used with this instrument.
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If you choose “yES”, after you press the REC/ENTER button the instrument
will prompt you to confirm that decision by displaying the term “Ent” below “yES”
and sounding three beeps. To confirm that you want to begin the erasure/formatting
procedure, press the REC/ENTER. “Ent” will then flash several times and the
instrument will sound another three beeps to confirm
that the SD card has been erased and formatted.
Once the SD card has been formatted (or not), the display will then either return to
the first of the six steps in the setup sequence—setting the current date and time—
or show the term “ESC”. If “ESC” appears, press the POWER/ESC button to exit the
setup procedure and enter normal operating mode.
NORMAL OPERATION
The DLM112SD can measure and store two different kinds of values:
• The intensity of light, in lux or footcandles. The unit lux is analogous to the
radiometric unit mW/cm2, but with the power at each wavelength weighted
according to the luminosity function, a standardized model of human visual
brightness perception. One footcandle = 10.764 lux.
• Temperature (in oF or oC), as sensed by a Type K or Type J thermocouple.
Pressing and holding the FUNC./ OLD/NEXT button will bring up, in order, two blank
five-digit displays above the terms “LIg t” and “tP” (for temperature). Each display
also automatically shows the correct unit for the parameter.
1. To choose the measurement function, release the FUNC./ OLD/NEXT button
when the desired parameter appears. This becomes the instrument’s default
measurement function until you change it.
2. To measure the intensity of light, plug the light probe (with its sensor cap on)
into the socket at the top of the DLM112SD (callout 1-7) and use the
FUNC. OLD/NEXT button to select light measurement mode. If the display shows
a value other than zero, press the LOGGER ▲button and hold it for at least
three seconds until you hear a beep. Then remove the cap from the probe.
olding the sensor housing, point the sensor directly at the light source whose
intensity you wish to measure. The display will indicate the intensity in units of lux.
To change the unit of measurement to footcandles (Ft-cd), press the REC/ENTER
button. The last unit selected becomes the default unit.
3. To measure temperature, first make sure that the light probe is not plugged into
the instrument. Then use the FUNC. OLD/NEXT button to select temperature
measurement mode and plug either a Type K or Type J thermocouple into the
socket (callout 1-8) on the top of the DLM112SD. The display will read out the
sensed temperature in degrees F or C, depending on the setting chosen during
setup.
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To change the unit of measurement, or to configure the instrument for use with a
Type J thermocouple probe, press the SET ▼button to reenter setup mode and
perform Step 7 or 8 of the procedure. Along with the measured value, the display also
shows the type of thermocouple the DLM112SD is configured for.
Whenever the DLM112SD is in measurement mode, you can turn off the backlight
(which is on by default) by briefly pressing (but not holding) the POWER/ESC button.
To reactivate the backlight, briefly press the button again.
Whenever the instrument is in measurement mode, you also can check the current
date and time by briefly pressing the SET ▼button. Doing so causes both values to
appear briefly at the lower left of the display.
HOLDING AND STORING MEASUREMENTS
4. To hold a measured value of light intensity or temperature, press the
FUNC./ OLD/NEXT button during the measurement. Doing so will cause the word
“ OLD” to appear at the top of the display. Pressing the FUNC./ OLD/NEXT button
again releases the hold.
5. To record and recall readings, press the REC/ENTER button while making
measurements. This will make the term “REC” appear at the top of the display.
Pressing the REC/ENTER button again, briefly, will make the term “MAX” appear to
the right of “REC” and switch the display to the maximum value stored in memory
during the last recording session. Pressing the REC/ENTER button again, briefly,
will make the term “MIN” appear to the right of “REC” and switch the display to
the minimum value stored during
the last session.
6. To exit recording mode, press and hold the REC/ENTER button for at least three
seconds, until the term “REC” disappears from the top line of the display. The
display will then revert to showing the current reading.
AUTOMATIC VS. MANUAL DATALOGGING
The DLM112SD can automatically log data using any of 11 sampling times from 1
second to 1 hour. To view the sampling time for which the instrument was set up,
press the LOGGER ▲button once. To change the datalogging sampling time, perform
Step 9 of the setup procedure.
7. To start automatic datalogging, press the REC/ENTER button once. The top line
of the display will then show the term “REC”. Pressing the LOGGER ▲button at
this point will make REC flash and add the flashing term “LOGGER” at the top right
of the display. This indicates that the instrument is currently storing measured
values and their time stamps in memory.
8. To pause automatic datalogging, press the LOGGER ▲button once; this action
makes the flashing term LOGGER disappear from the top right of the display and
changes the term “REC” from flashing to constant. Pressing the LOGGER ▲button
again resumes automatic datalogging.
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9. To end automatic datalogging, press the REC/ENTER button and hold it for at
least two seconds. This action causes the “REC” message to disappear.
10. To log data manually, set the sampling time to zero Step 9 of the setup
procedure. Then press the REC/ENTER button once. The display will show the
term “REC” on the top line, a value in the middle, and below it the letter “P” on
the left and a number from 1 to 99 on the same line to the right.
The number indicates the position on the SD card that will be used to store
manually logged data.
Now press the LOGGER ▲button. This will cause the beeper to sound and the term
“LOGGER” to briefly appear at the upper right of the display. As in automatic
datalogging mode, in this mode the instrument is storing measurements and their
time stamps on the SD card.
In manual datalogging mode, however, measurements are being stored continuously
(with a sampling time of zero), and their locations on the card can be changed.
11. To change the storage location of manually logged data, press the
SET ▼button once; this causes the “P” to disappear from the left side of the
display and the value on its line to begin flashing. Once the flashing begins, you
can use the SET ▼and LOGGER ▲buttons to change the flashing value to any
number between 1 and 99. Once you have chosen the storage location, press the
REC/ENTER button to save the setting. This causes the value to stop flashing and
the “P” to return.
12. To end manual datalogging, press the REC/ENTER button and hold it for at least
three seconds. This action causes the “REC” message to disappear from the top
line of the display.
TRANSFERRING DATA FROM THE
SD CARD TO A COMPUTER
After automatic or manual datalogging of measurements, remove the SD card from
the DLM112SD and plug it into your computer either directly (if it has an SD card slot)
or through an SD card reader.
Because the files containing time-stamped data logs have the file extension .xls, they
open in Microsoft’s Excel application. Figures 2 and 3 show two kinds of Excel
presentations: a data-only screen and a graphics-only screen.
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