Amprobe LM631A User manual

User Manual
LM631A
Digital Light Meter

LM631A
Digital Light Meter
English

Limited Warranty and Limitation of Liability
Your Amprobe product will be free from defects in material and
workmanship for 1 year from the date of purchase. This warranty
does not cover fuses, disposable batteries or damage from accident,
neglect, misuse, alteration, contamination, or abnormal conditions
of operation or handling. Resellers are not authorized to extend
any other warranty on Amprobe’s behalf. To obtain service during
the warranty period, return the product with proof of purchase to
an authorized Amprobe Test Tools Service Center or to an Amprobe
dealer or distributor. See Repair Section for details. THIS WARRANTY
IS YOUR ONLY REMEDY. ALL OTHER WARRANTIES - WHETHER
EXPRESS, IMPLIED OR STAUTORY - INCLUDING IMPLIED WARRANTIES
OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY,
ARE HEREBY DISCLAIMED. MANUFACTURER SHALL NOT BE LIABLE
FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL
DAMAGES OR LOSSES, ARISING FROM ANY CAUSE OR THEORY. Since
some states or countries do not allow the exclusion or limitation of
an implied warranty or of incidental or consequential damages, this
limitation of liability may not apply to you.

Digital Light Meter
Contents
INSTRUCTIONS........................................................................................1
CERTIFICATIONS AND PRECAUTIONS ....................................................1
OPERATION.............................................................................................2
SPECIAL CONSIDERATIONS ....................................................................2
MAINTENANCE.......................................................................................3
REPAIR.....................................................................................................3
SPECIFICATIONS ......................................................................................6
ELECTRICAL.............................................................................................7

HOLD PEAK RANGE
> 2sec
HP MAX
X10 lux fc
6
fc
lux
o
fc
lux
o
5
4
3
2
1
7
LM631
LIGHTMETER

1
Instructions
CERTIFICATIONS AND PRECAUTIONS
The LM631A instrument is EN61326-1 certified for EMC and EMI.
Do not use any damaged part.
Do not operate instrument in an explosive atmosphere. It is
recommended that you read the safety and operation instructions
before using the Light meter. The symbol on the instrument indicates
that the operator must refer to an explanation in this manual. It is
recommended that you read the safety and operation instructions
before using the light meter.
INTRODUCTION
This instrument is a portable easy use 3½ digit, compact sized digital
light meter designed for simple one hand operation with the reading in
lux or fc units. Its controls are:
1. Sensor Head.
2. RANGE button.
3. PEAK HOLD (50 mS pulse light) button and Back light switch.
4. DATA HOLD button.
5. Lux / fc / OFF selector
6. mV output jack.
7. LCD display.
Back Light: Press the ‘PEAK’ button for greater than 2 seconds to toggle
the backlights ON and OFF.
PEAK- HOLD button: Press the ‘PEAK’ button to toggle the PEAK
Hold function ON and OFF. In the PEAK-HOLD mode, the “
PM A X
“
annunciator is displayed and the last reading is held on the display. If
the new reading exceeds the previous reading and the new value is
displayed.

2
RANGE Button: Each time you press ‘RANGE’ button, the range
annunciators change
DATA-HOLD Button: Press ‘HOLD’ button to toggle the DATA-HOLD
mode On and Off. In the DATA-HOLD mode, the “
H
“ annunciator is
displayed and the last reading is held on the display.
Auxiliary output: The microphono jack (2.5 mm) connector output is
active as long as the light meter is turned on.
OPERATION
1. Set the function switch to the desired lux or fc units.
2. Remove the sensor head cover.
3. Hold the sensor head steady and make certain that the light source
completely fills the cosine correction dome.
4. Move away from the sensor head to avoid shadowing it.
The sensor head has a 1.5 meter cable to allow separation between the
observer and the measurement location.
5. Read the luminance value from the display. If magnitude of lux (or fc)
is not known, press RANGE button to the highest range and reduce until
a satisfactory reading is obtained.
6. Cover sensor head to extend sensor life.
SPECIAL CONSIDERATIONS
• Keep the plastic domed cosine corrector clean and free of scratches. It
may be cleaned with a soft cloth and isopropyl alcohol.
• When light is received from many directions simultaneously, take
special care to avoid reflections or shadowing the sensor with your
body.
• For best accuracy, repeat the measurement several times to ensure

3
that the light source has remained stable.
• Avoid exing the cable excessively at either end of the cable.
MAINTENANCE
In Case of Difficulties: In the case of improper operation of
the light meter, first review the operating instructions for possible errors
in operation. Check the condition of the batteries. The battery “
+ -
”
symbol appears when the voltage falls below the level where accuracy is
guaranteed. Replace the batteries immediately.
Battery Replacement
To replace the batteries ( 4 – AAA) unscrew the battery hatch screw
and remove the old batteries. Install the new batteries observing the
diagram in the battery area.
Cleaning Procedure
Gently wipe dirt from the surface of the unit with a soft cloth moistened
with a small amount of water or neutral cleanser. Do not use benzene,
alcohol, acetone, ether, paint thinner, lacquer or ketone solvents on
the units, under any circumstances as these may cause deformation or
discoloration.
REPAIR
Read the warranty located at the front of this manual before requesting
warranty or non-warranty repairs. For warranty repairs, any lightmeter
claimed to be defective can be returned to any Amprobe Test Tools
authorized distributor or to a Amprobe Test Tools Service Center for an
over-the-counter exchange for the same or like product. Non-warranty
repairs should be sent to a Amprobe Test Tools Service Center. Please call
Amprobe Test Tools or enquire at your point of purchase for the nearest
location and current repair rates. All light meters returned for warranty
or non-warranty repair or for calibration should be accompanied by
the following information or items: company name, customer’s name,
address, telephone number, proof of purchase (warranty repairs), a

4
brief description of the problem or the service requested, and the
appropriate service charge (for non-warranty repairs). Service charges
should be remitted in the form of a check, a money order, credit card
with expiration date, or a purchase order made payable to Amprobe
Test Tools or to the specific service center. For minimum turn-around
time on out-of-warranty repairs please phone in advance for service
charge rates. The light meter should be shipped with transportation
charges prepaid to one of the following addresses or to a service center:
in U.S.A. in Canada
Amprobe Amprobe
1420 75th Street SW 400 Britannia Rd. E.Unit #1
Everett, WA 98203 Mississauga, ON L4Z 1X9
Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone]
The instrument will be returned with the transportation charges paid by
Amprobe Test Tools.

5
SPECIFICATIONS
GENERAL
Display: 3½ digit LCD with maximum reading of 1999
Overrange: (OL) is displayed
Low battery indication: “
+ -
“ is displayed
Measurement rate: 2.5 times per second, nominal.
Operating Environment: 0 °C to 50 °C (32 °F to 122 °F) at < 75% R.H.
Storage Temperature: -20 °C to 60 °C (-4 °F to 140 °F), 0 to 80 %
R.H. with batteries removed
Environment: Indoor use, Altitude up to 2000 m.
Battery: 4 pcs 1.5V (AAA size) UM-4, R03
Battery Life: 200 hours typical with carbon zinc battery
Dimensions: 170 x 44 x 40 mm
Weight: 220g (7.76oz) including batteries
EMC: Conforms to EN61326-1. This product complies with requirements
of the following European Community Directives: 89/ 336/ EEC (Electro-
magnetic Compatibility) as amended by 93/ 68/ EEC (CE Marking).
However, electrical noise or intense electromagnetic fields in the vicinity
of the equipment may disturb the measurement circuit. Measuring
instruments will also respond to unwanted signals that may be present
within the measurement circuit. Users should exercise care and take
appropriate precautions to avoid misleading results when making
measurements in the presence of electronic interference.

6
ELECTRICAL
Accuracy: at 23°C ± 5°C (73°F ± 9°F), < 75 % relative humidity
Ranges: 20 lux, 200 lux, 2000 lux, 20000 lux
20 fc, 200 fc, 2000 fc, 20000 fc
Total accuracy for CIE standard illuminant A (2856K):
±( 3 % rdg + 10 dgts)
Temperature Coefficient: 0.1x (specified accuracy)/°C (< 18°C or >28 °C),
0.056 x(specified accuracy)/°F (< 64.4°F or > 82.4°F)
Resolution: 0.01lux; 0.01fc
Spectral response: CIE photopic – CIE standard illuminant A
Acceptance angle: ƒ ’ 2< 2 %; cosine corrected (150°)
Peak Hold response time: >50mS pulse light.
Analog output: 1 mV = 1 lux or 10 mV = 1 fc , nominal, continuous
output
The CIE photopic curve is an international standard for the color
response of the average human eye. CIE standard illuminant A
is defined as: A gas- filled tungsten-filament lamp operating at a
correlated color temperature of 2856K.