YOKOGAWA 51011 User manual

User’s
Manual 51011, 51012, 51021
Digital Lux Meter
IM 51011-01EN
4th Edition: Oct. 2017 (YMI)
Store this manual in an easily accessible
place for quick reference.

IM 51011-01EN 1
Introduction
Thank you for purchasing the digital lux meter.
This user’s manual primarily explains the handling precautions and
basic operations of the digital lux meter.
To ensure correct use, please read this manual thoroughly before
beginning operation.
After reading this manual, keep it in a safe place.
List of Manuals
The following manuals, including this one, are provided as manuals
for the digital lux meter. Please read all manuals.
IM 51011-01E User's Manual (this manual)
IM 51011-93Z2 Document for Korea
Contact information of Yokogawa offices worldwide is provided on
the following sheet.
PIM 113-01Z2 Inquiries List of worldwide contacts
Notes
• The contents of this manual are subject to change without prior
notice as a result of continuing improvements to the instrument’s
performance and functionality. The figures given in this manual
may differ from the actual screen.
• Every effort has been made in the preparation of this manual to
ensure the accuracy of its contents. However, should you have
any questions or find any errors, please contact your nearest
YOKOGAWA dealer.
• Copying or reproducing all or any part of the contents of
this manual without the permission of YOKOGAWAis strictly
prohibited.

IM 51011-01EN
2
4th Edition: October 2017 (YMI)
All Rights Reserved, Copyright ©
2013, Yokogawa Meters & Instruments Corporation,
2017, Yokogawa Test & Measurement Corporation
Printed in Japan
Trademarks
• Adobe, Acrobat, and PostScript are either registered trademarks
or trademarks of Adobe Systems Incorporated.
• In this manual, the ® and TM symbols do not accompany
their respective registered trademark or trademark names.
• Other company and product names are registered trademarks
or trademarks of their respective companies.
Revisions
• February 2013 1st Edition
• October 2013 2nd Edition
• May 2013 3rd Edition
• October 2017 4th Edition

IM 51011-01EN 3
Checking the Contents of the Package
Unpack the box and check the contents before operating the
instrument. If the wrong items have been delivered, if items are
missing, or if there is a problem with the appearance of the items,
contact your nearest YOKOGAWAdealer.
Digital Lux Meter
Check that the product that you received is what you ordered by
referring to the model name on the name plate.
MODEL Specifications
51011 JIS Class A
Measurement ranges: 99.9/999/9,990/99,900/999,000
51012 JIS Class AA
Measurement ranges: 99.9/999/9,990/99,900/999,000
51021 JIS Class AA
Measurement ranges:
9.99/99.9/999/9,990/99,900/999,000
51011, 51012: Single-function model
Compliant standard: JIS C 1609-1: 2006
(JIS: Japanese Industrial Standards)
Standard Accessories
AA-size alkaline batteries 2
Recorder output plug (JC017A) 1
Soft-sided case (RB038A) 1
User’s Manual (Japanese and English) 2
Optional Accessories (Sold separately)
Item Specifications Model
Light-detector extension
cable 3 m 91001
30 m 91002

IM 51011-01EN
4
Conventions Used in This Manual
Notes and Cautions
The notes and cautions in this manual are categorized using
the following symbols.
Improper handling or use can lead to injury to
the user or damage to the instrument.
This symbol appears on the instrument to
indicate that the user must refer to
the user's manual for special instructions.
WARNING
Calls attention to actions or conditions that
could cause serious or fatal injury to the user,
and precautions that can be taken to prevent
such occurrences.
CAUTION
Calls attention to actions or conditions that could
cause light injury to the user, or cause damage
to the instrument or user’s data, and precautions
that can be taken to prevent such occurrences.
Note Calls attention to information that is important for
the proper operation of the instrument.

IM 51011-01EN 5
Safety Precautions
This product is designed to be used by a person with specialized
knowledge.The general safety precautions described herein must
be observed during all phases of operation. If the instrument
is used in a manner not specified in this manual,
the protection provided by the instrument may be impaired.
This manual is an essential part of the product; keep it a safe
place for future reference.
YOKOGAWA assumes no liability for the customer’s failure to
comply with these requirements.
The following symbols are used on this instrument.
Warning: handle with care.
Refer to the user’s manual or service manual.
This symbol appears on dangerous locations on
the instrument which require special instructions for
proper handling or use.
The same symbol appears in the corresponding
place in the manual to identify those instructions.
Make sure to comply with the precautions below.
Not complying might result injury or death.
WARNING
Use the instrument Only for Its Intended Purpose
The lux meter is for measuring illuminances.
Do not use this meter for any other purpose.
Check the Physical Appearance
Do not use the meter if there is a problem with its physical appearance.
Do Not Disassemble
Only qualified YOKOGAWApersonnel may disassemble this product.
Do Not Operate in an Explosive Atmosphere
Do not use this meter in the presence of flammable gases or vapors.
Doing so is extremely dangerous.

IM 51011-01EN
6
CAUTION
• The meter is for domestic use (Class B) and meets the
electromagnetic compatibility requirements.
• Do not drop the meter or strike it against hard objects.
• Avoid storing the meter in direct sunlight or in a humid environment.
• Using the meter in an low-temperature environment (–10°C to 0°C)
may slow down the display’s response.
• Avoid using the meter in a dirty or dusty environment or
in an environment with salt or corrosive gases.
• Do not wipe the meter with organic solvents.
Dirt or dust adhering to the light-detecting surface of the meter
decreases measurement accuracy.
Wipe the surface clean with a soft, dry cloth.
• Do not separate the light-detector from the main unit with
the power on.

IM 51011-01EN 7
Measurement Category
WARNING
• Do not use the meter for measurements in locations falling
that fall under Measurement Categories II, III, and IV.
• Do not use the meter to measure voltage or current.
The meter is designed for measurement category I:
EN 61010-1: 2001
Measurement
Category Description Remarks
CAT I
For measurement performed on
circuits not directly connected to
MAINS.
CAT I: EN 61010-1: 2001
Circuits not connected
to a mains power
source.
CAT II For measurement performed on
circuits directly connected to
the low-voltage installation.
Appliances, portable
equipment, etc.
CAT III For measurement performed in
the building installation. Distribution board, circuit breaker, etc.
CAT IV For measurement performed at
the source of the low-voltage
installation.
Overhead wire,
cable systems, etc.

IM 51011-01EN
8
Contents
Introduction.............................................1
Checking the Contents of the Package .......................3
Conventions Used in This Manual ...........................4
Safety Precautions .......................................5
Measurement Category ...................................7
1. Component Names and Functions........................9
2. Before Operation ....................................14
2.1 Measurement Functions ..........................14
2.2 Turning the Power On and Off......................14
2.3 Setting the Response ............................15
2.4 Checking and Replacing Batteries ..................16
2.5 Automatic Power Off .............................16
2.6 Notes on Illuminance Measurement .................18
3. Normal Illuminance Measurement .......................19
4. Color Correction Measurement (K Key) ...................20
5. Timer Hold (HOLD and T-H Keys) .......................22
6. Range Hold (RANGE Key) .............................24
7. Average Illuminance (AVG Key).........................25
8. Deviation Display (Δ/% Key)............................27
9. Light Source Luminous Intensity (cd Key) .................28
10. Totalized Intensity of Illumination
(ACC Key) .........................................29
11. Comparator (COMP Key)..............................32
12. Ripple Measurement (S-F Key) .........................33
13. Communication Functions .............................36
13.1 Cable Connection and Interface Specifications.........36
13.2 List of Commands ...............................37
13.3 Detailed Description of Commands..................38
14. Recorder Output (Analog Output) .......................41
15. Separating the Light Detector...........................42
16. Supplying Power through USB ..........................42
17. After-Sales Service...................................43
17.1 Error Messages .................................43
17.2 Calibration .....................................43
18. Specifications .......................................44
19. Characteristics of Relative Visible-
spectrum Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
20. Characteristic of Oblique Incident Light ...................51
21. Illuminance Measurement Method .......................52
22. For the Pollution Control of Electronic
and Electrical Products of the People's Republic of China.....55

IM 51011-01EN 9
1. Component Names and Functions
Light-detecting surface
Display
Main unit
Hand strap
Keys
Cap
Protects the
light-detecting surface
Used also during
automatic
zero adjustment
Light detector
Can be separated
from the main unit
(using an extension
cable)
USB port
(mini B type)
Use the USB cable
to communicate to the PC
and supply power.
POWER key
Turns the power
on and off