YOKOGAWA 51001 User manual

RG102
5th Edition
Apr. 2007
51001
Digital
Illuminance Meter
User’s
Manual

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CONTENTS
Overview ...................................................................................................... 2
Prior to Use................................................................................................... 3
Operation ...................................................................................................... 5
Illuminance Measurement .......................................................................... 11
Data Hold ............................................................................................. 12
Timer Hold ........................................................................................... 13
Range Hold .......................................................................................... 13
Deviation Display ................................................................................ 14
Data Output ................................................................................................ 16
Recorder Output (Analog Output).............................................................. 19
Separation of Light Detector ...................................................................... 20
After-sales Servicing .................................................................................. 21
Specifications ............................................................................................. 22
Characteristics of Relative Visible-spectrum Response............................. 23
Characteristic of Oblique Incident Light .................................................... 25
Illuminance Measurements for Lighting Installations
(Extract from JIS C 7612 standards) .......................................................... 26
Copyright Nov. 1994 (YG). 5th Edition: Apr. 2007 (KP)

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Overview
Thank you very much for purchasing our Digital Illuminance Meter. Prior
to its use, thoroughly read this instruction manual to observe the correct
way of use.
Our digital illuminance meter is a small, lightweight meter and enables
illuminance measurements with the meter separated from the light detector.
The display adopts a large liquid crystal display (LCD) for ease in reading,
and attention is also paid to operation key arrangement. The photoelectric
element adopts a silicon photodiode for correcting the spectral luminous
efficiency by combining with an optical filter in order to measure the
illuminance of natural light. There is a microcomputer incorporated in this
meter to realize an illuminance meter having excellent functions. There are
also various functions incorporated in this meter, not found in conventional
meters: a data-hold function; a timer-hold function; deviation display; an
automatic power-off function; a response selection function; and others.
Refer to the text for details on these respective functions. Moreover, this
illuminance meter provides recorder output and digital data output, further
extending its usefulness. Thus, the range of applications of this meter is
much more extensive than that of existing luxmeters (illuminance meters).
This digital illuminance meter has been designed, manufactured, and
delivered under strict quality control criteria by a factory certified in the
ISO 9001 Quality Standards. We hope you will be able to make sufficient
use of the performance of this product, in addition to our traditional
photocell luxmeters.
Please retain this instruction manual for future use in operating this product.

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Prior to Use
Checking accessories
After unpacking the meter, check it for appearance and its accessories.
Accessories: Instruction manual: 1
Recorder output plug (JC017A): 1
Soft-sided case (RB038A): 1
One dry cell battery (9 V) in the meter.
Precautions on Handling
·Exercise care not to drop the meter or hit it with a hard object.
·Avoid placing the meter in a room at a temperature above 60°C or below -
20°C. Also, avoid placing it in an area subject to direct sunlight or at a
high humidity.
·Using the meter at low temperatures (between -10 and 0°C) causes the
display response to be delayed.
·Avoid using the meter in a dirty, dusty, or salt-air area or where there are
corrosive gases.
·Dirt or dust adhering to the light-detecting surface decreases measurement
accuracy. Wipe the surface clean with a soft, dry cloth.
·Do not use solvent (trichloroethylene, paint thinner, benzene, alcohol,
etc.), which may deform the case material or cause the print to peel off.
To remove stains from the case, gently wipe them off with a soft cloth.
If the instrument is badly stained, use a soft cloth moistened with a neutral
detergent, then wipe off the moisture using a dry cloth.
·Do not disassemble the meter.
·Do not separate mainunit from light-detector with the power on.
Safety Summary
The CAUTION Which appear on the following page must be followed to
ensure operator safety and to retain the operating condition of the
Illuminance Meter,
Safety Symbol
Indicates the operator must refer to an explanation in this manual.

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Calibration
Calibrate the meter once every two years in order to maintain accurate
measurements. Calibration is done by Yokogawa. To have the meter
calibrated, consult the Yokogawa sales representative from whom you
purchased the instrument or the Yokogawa sales division listed on the
back of this manual.
Optional Accessories
SpecificationProduct
Light-detector extension cable
Data output cable
AC adaptor
Model
3m
30m
3m
120 V (DC 9V)
220 V (DC 9V)
910 01
910 02
910 03
940 01
940 02
Note
Accessories of non-standard
Safety standard: EN 61010-1
· AC adapter Model: 94001(Input of 120 V±10% AC)
Model: 94002(Input of 220 V±10% AC)
EMC standard:
· Light-detector extension cable
Model: 91002(Cable length: Approx. 30 m)
Danger of electrical shock!
·When you use the AC adaptor, never use a power supply that is not suited to
the adaptor.
·Handle the AC adaptor with care so that the adapter is not damaged. If the
adaptor is damaged, do not use it.
CAUTION

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Operation
Components
Cap
Light detector
Light-detecting surface
Display area
Main unit
Power switch
∆/% key
Range key
Hand strap
Data output connector AC adaptor input
Figure 1. Components

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Measuring reference plane indication
Tripod-mounting screw Recorder output
connector
Hold switch
Eject button
Rating nameplate
Battery cover Response selector
switch

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Display Area
Figure 2. All Display Elements (some are unused)
Description of Elements in Display Area
Display condition/indication
Digital display of measured value, calculated value, and set value
Indicates meter in automatic power-off mode
Deviation
Indicates when a plug is inserted into the recorder output connector
Indicates range hold
Indicates data hold and timer hold
Indicates low battery voltage
Response setup display
Unit of illuminance
Unit of illuminance
Deviation display (%)
Element
8,8.8.8,8.8.8
AUTO POWER OFF
∆
R–H
RSPS
lx
fc
%
REC
+ –
D–H

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Prior to Operation
1. Response Time Setup
The response speed of the light detector can be selected using the response
selector switch. The response speed is set as described below. Set the
switch to FAST or SLOW according to its application. When FAST is set,
[RSPS
F
] appears; when SLOW is set, [RSPS
S
] appears in the display
area.
Response speedSwitch position Application
Approx. 10 mS
Approx. 500 mS
Measurement of continuous light
Daylight, interior lighting (fluorescent
lamps, incandescent lamps), etc.
Measurement of average illuminance
such as flickering lights or variations
from measuring beams such as TV screens
FAST
SLOW
Note: If the recorder output is used for waveform observation, set the
switch to FAST
2. Replacement of Battery
If the battery voltage drops during operation, a [ ] sign appears in the
display area. In this case, replace the battery with a new one immediately.
Check the polarity markings in the battery compartment and battery’s
polarity in order to avoid putting in the battery incorrectly. Use either a
6F22 9-V dry cell battery (S-006P, manganese, with approximately a 25-
hour service life) or a 6LR61 9-V dry cell battery (alkaline dry cell battery
with approximately a 40-hour service life).
Battery cover
Battery
Main unit
Figure 3. Replacement of Battery

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3. Selection of Units of Measurement (lx, fc)
Since this illuminance meter conforms to the International System of Units
(SI units), the lux (lx) is regarded as the reference unit. Some countries use
the footcandle (fc) which is not an SI unit. For this reason, this illuminance
meter provides a function to display readings converted to fc units with a
unit selector switch. Select the desired unit, as needed, prior to measure-
ment.
Be sure to turn off the power before selection.
Figure 4 shows the location of the lx-fc selector switch. Note that the
specifications and operation description in this manual are based on the lux.
Figure 4. Location of lx-fc Selector Switch
4. Automatic Power Off (AUTO POWER OFF)
This digital illuminance meter provides an automatic power-off function in
order to avoid using up the battery if you forget to turn off the power. This
function turns the power off about 30 minutes after any key is last pressed.
Immediately before turning the power off, the meter makes a beeping
sound. If you press any of the operation keys while the beeping sound is
on, this will extend the time of the automatic power-off function by 30
minutes. Whenever a plug is in the recorder output connector while the