Rion NL-21 User manual

INSTRUCTION MANUAL
Sound Level Meter
NL-21 / NL-31
3-20-41 Higashimotomachi, Kokubunji, Tokyo 185-8533, Japan
http://www.rion.co.jp/english/

i
Organization of the NL-21/NL-31 Documentation
The documentation for the Sound Level Meter NL-21/NL-31 consists of three
separate manuals.
zInstruction Manual (this document)
Describes operating procedures for the Sound Level Meter NL-21/ NL-31,
connection and use of peripheral equipment such as a level recorder and printer,
and use of the memory card.
zSerial Interface Manual
Describes how to use the serial interface built into the Sound Level Meter
NL-21/NL-31. The manual covers the communication protocol, use of
control commands for the sound level meter, format of data output by the
sound level meter, and other topics.
zTechnical Notes
This document provides in-depth information about the circuit
configuration and performance of the sound level meter, microphone
construction and characteristics, influence of extension cables and
windscreen on the measurement, and other topics.
* Company names and product names mentioned in this manual are usually
trademarks or registered trademarks of their respective owners.

ii
To conform to the EU requirement of the Directive
2002/96/EC on Waste Electrical and Electronic
Equipment, the symbol mark on the right is shown
on the instrument.

iii
Organization of This Manual
This manual describes the features, operation and other aspects of the General-
Purpose Sound Level Meter NL-21 and High-Precision Sound Level Meter
NL-31.
The manual contains the following sections.
Outline
Gives basic information about the configuration and features of the
unit, and also contains a block diagram.
Controls and Functions
Briefly identifies and explains the controls and connectors and all other
parts of the unit.
Preparations
Gives information about power supply, pre-use checks, installation,
connections, key settings etc.
Reading the Display
Explains the symbols and other information appearing on the display
of the unit.
Power On/Off
Explains how to turn the unit on and off.
Measurement
Explains how to perform measurement.
Store Operations
Explains how to store measurement results in the memory of the unit.
Memory Card
Explains how to use memory cards with the unit.

iv
Default Settings
Lists the factory default settings of the unit.
Output Connectors
Explains the output connectors of the unit.
Optional Accessories
Explains how to use external equipment for example to store measure-
ment data.
Messages
Explains the various messages that may appear on the screen.
Specifications
Lists the technical specifications of the unit.

v
FOR SAFETY
In this manual, important safety instructions are specially marked as shown below.
To prevent the risk of death or injury to persons and severe damage to the unit or
peripheral equipment, make sure that all instructions are fully understood and observed.
Caution
Important Disregarding instructions
printed here incurs the risk of
damage to the product.
Disregarding instructions
printed here incurs the risk of
injury to persons and/or dam-
age to peripheral equipment.
Mentioned about the tips to use
this unit properly. (This mes-
sages do not have to do with
safety.)
Note
1234567890123456789012345678901212345678901234567890123456789012123456789012
1
23456789012345678901234567890121234567890123456789012345678901212345678901
2
1234567890123456789012345678901212345678901234567890123456789012123456789012

vi
Precautions
zOperate the unit only as described in this manual.
zProtect the unit from shocks and vibration. Be especially careful not to
touch the microphone membrane to avoid damage. The membrane is an
extremely thin metal film which can be damaged easily.
zDo not use the unit with a different microphone/preamplifier from the
one indicated on the name plate of the unit.
zAmbient conditions for operation of the unit are as follows: temperature
range -10 to +50°C, relative humidity 10 to 90%.
Protect the unit from water, dust, extreme temperatures, humidity, and
direct sunlight during storage and use. Also keep the unit away from air
with high salt or sulphur content, gases, and stored chemicals.
zAlways turn the unit off after use. Remove the batteries from the unit if it
is not to be used for a long time. When disconnecting cables, always
grasp the plug and do not pull the cable.
zBefore using the microphone and before putting it away, always check
that the microphone grid has not become loose. If this has happened,
refasten the microphone grid firmly and then use or store the microphone.
zClean the unit only by wiping it with a soft, dry cloth or, when necessary,
with a cloth lightly moistened with water. Do not use any solvents, cleaning
alcohol or cleaning agents.
zDo not try to disassemble the unit.
In case of an apparent malfunction, do not attempt any repairs. Note the
condition of the unit clearly and contact the supplier.
zDo not tap the LCD panel or other surfaces of the unit with a pointed
object such as a pencil, screwdriver, etc.
zTake care that no conductive objects such as wire, metal scraps, conductive
plastics etc. can get into the unit.
zTo ensure continued precision, have the unit checked and serviced at
regular intervals.
zWhen disposing of the unit, be sure to observe all applicable legal
regulations and guidelines in your country and community.

vii
Quantifier Notation of Sound Level Meter NL-21/NL-31 According to
International Standards and JIS
(Excerpts from ISO 1996, 3891, IEC 61672-1:2002, JIS Z 8202, 8731)

viii
Contents
FOR SAFETY .................................................................................... v
Outline ................................................................................................ 1
Controls and Functions ...................................................................... 4
Front View .................................................................................... 4
Operation Keys ............................................................................. 5
Bottom View ................................................................................. 8
Rear View...................................................................................... 9
Preparations ...................................................................................... 10
Power Supply .............................................................................. 10
Windscreen (WS-10) .................................................................. 13
Tripod Mounting......................................................................... 13
Memory Card, Program Card ..................................................... 14
Microphone Extension Cables (EC-04 series)............................ 15
Connection to a Printer (DPU-414, CP-11, CP-10).................... 17
Connection to a Level Recorder
(LR-06, LR-07, LR-04, LR-20A).................................... 20
Connection to a Computer .......................................................... 20
Setting the Date and Time .......................................................... 21
Measurement in Dark Locations................................................. 23
LCD Contrast.............................................................................. 24
Calibration .................................................................................. 25
Language selection ..................................................................... 30
Reading the Display ......................................................................... 31
Display screen............................................................................. 31
Menu screens .............................................................................. 36
Power On/Off ................................................................................... 45

ix
Measurement .................................................................................... 47
Sound level Measurement........................................................... 47
Equivalent Continuous Sound level (LAeq) Measurement .......... 50
Sound Exposure Level (LAE) Measurement................................ 55
Maximum (Lmax) and Minimum (Lmin) Sound level
Measurement ................................................................... 60
Percentile Sound level (LN) Measurement .................................. 65
Measurement of Auxiliary Processing Values
(Lpeak, LCpeak, LCeq, LAtm5, LAI, LAIeq) ............................... 71
Back-Erase Function................................................................... 77
Store Operations ............................................................................... 79
Manual Store............................................................................... 81
Auto 1 ......................................................................................... 89
Auto 2 ......................................................................................... 95
Memory Card ................................................................................. 103
Memory Card............................................................................ 103
Data size ................................................................................... 104
Store Data Format ..................................................................... 106
Default Settings .............................................................................. 111
Output Connectors ......................................................................... 112
AC Output................................................................................. 112
DC Output ................................................................................ 113
I/O Connector ........................................................................... 114
Optional Accessories ...................................................................... 115
Microphone Extension Cables EC-04 Series............................ 115
Printer DPU-414/CP-11/CP-10 ................................................ 116
Level Recorder LR-06/LR-07/LR-04/LR-20A......................... 124
Program Cards .......................................................................... 126
Messages ........................................................................................ 136
Specifications ................................................................................. 141

x

1
Outline
The Sound Level Meter NL-21 and NL-31 are designed for sound level
measurements according to the IEC standard.
The following measurements can be made:
zEquivalent continuous sound level Leq
zSound exposure level LE
zMaximum sound level Lmax
zMinimum sound level Lmin
zPercentile sound level LN(five selectable settings)
zSound level Lp
zC-weighted peak sound level LCpeak
zFLAT peak sound level Lpeak
zImpulse sound level LAI
z Impulse equivalent continuous sound level LAIeq
zTakt-max sound level LAtm5
Measurement settings and results (level values and bar graph) are shown on
the backlit LCD panel.
Measurement data (sound level, processed data, measurement parameters) can
be stored in the internal memory of the unit or on a memory card (CompactFlash
card optional). The serial interface allows sending measurement data to a printer
or computer.
By loading an optional filter program, the unit can be used for 1/1 octave or 1/3
octave analysis with a 3rd-order Butterworth high-pass and low-pass filter.
Recorded data can be further processed on a computer.

2
Outline
The following accessories are optional, to cover a wide range of application
requirements.
zPrinter DPU-414
Serves to produce hard copy of measurement data (including data stored
in memory).
zLevel recorder LR-07/LR-20A
Serves to record sound level changes over time.

3
Outline
M I C / P r e a m p
A M P 1 A M P 2
A M P 6
A M P 7
A C O U T
D C O U T
F I L T E R O U T
K E Y S W
A T T
O V E R L O A D D E T .
S t a r t
S t o p S t o r e M o d e
P a u s e
C o n t
F a s t S l o w
M e n u P a g e R a n g e
R e c a l l
F r e q
L i g h t P r i n t
P o w e r
R e c a l l d a t a
D o w n
C a l a d j
C a l
U p
A C F L A T
E2P R O M C L K R S - 2 2 - C
P O W E R S U P P L Y
L C D R A M
D S P
C P U
A / D
D / A
C O N V .
A
F L A T
A M P
C
F L A T
A M P 4
A M P 5
A / D
D / A
C O N V .
A C D C O U T
, ) 6 )  * 7 5
A D D R E S S B U S
, ) 6 )  * 7 5
C A R D
I N T E R F A C E
A M P 8 A M P 1 0
V r e f .
A D D R E S S B U S
A M P 9
C A L . S I G .
A T T i s p l a c e d o n o n l y N L - 1 .
NL-21 / NL-31 Block Diagram

4
Controls and Functions
Front View
S t a r t
S t o p S t o r e M o d e
P a u s e
C o n t
F a s t S l o w
M e n u P a g e R ange
R e c a l l
F r e q
L i g h t P r i n t
P o w e r
S O U N D L E V E L M E E R
R e c a l l d a t a
D o w n
C a l a d j
C a l
U p
A C F L A
N L - 2 1
M i c r o p h o n e / p r e a m p l i f i e r
D i s p l a y
O p e r a t i o n k e y s
H a n d s t r a p
Microphone/preamplifier
The microphone and preamplifier are configured as an integrated assembly.
The assembly can be removed from the sound level meter and connected via
an optional extension cable, for measurements a distance.
Display
This backlit LCD shows the sound level as a numeric reading and a bar graph.
The display also shows the operation mode of the sound level meter, the selected
measurement parameters, warning indications etc.
Hand strap
Makes the unit easy to carry and hold on your palm.

5
Controls and Functions
Operation Keys
S t a r t
S t o p S t o r e M o d e P a u s e
C o n t
F a s t S l o w
M e n u P a g e R ange
R e c a l l
F r e q
Light P r i n t
P o w e r
S O U N D L E V E L M E E R
R e c a l l d a t a
D o w n
C a l a d j
C a l
U p
ACF L A
N L - 2 1
Start/Stop key
Press to start or stop the sound level measurement (including the various
processing functions).
Store key
Press to start auto store or store measurement data using manual store.
Mode key
This key is used for reading the measurement results. With each push of the
button, the display format is switched according to the processing types selected
from the menu.
Pause/Cont key
During a measurement, this key can be used to exclude unwanted portions
from processing. Pressing the key again causes processing to be resumed.
It is also possible to use the key for excluding an interval of up to 5 seconds
before the key was pressed.

6
Controls and Functions
Menu key
When this key is pressed, the menu screen 1/5 appears on the display. Pressing
the key again switches the display back to the original condition.
Menu pages are switched with the Page
D o w n U p
keys to the right of the
key.
A/C/FLAT key
Sets frequency weighting to A, C or FLAT.
Fast/Slow key
Sets the time weighting to Fast or Slow.
Level Range , keys
Select the level range for the measurement.
The following six settings are available:
20 to 80, 20 to 90, 20 to 100, 20 to 110, 30 to 120, 40 to 130
With the filter function activated, the following seven settings are available:
10 to 70, 20 to 80, 30 to 90, 40 to 100, 50 to 110, 60 to 120, 70 to 130
Recall key
Serves to recall data stored in the memory of the unit.
Recall Data , keys
When the display shows the measurement screen and the manual store mode
is selected, these keys select the data number in which to store data next.
When the display shows data from memory, the keys select the data number to
be displayed. When the filter function is active, this key serves to switch filter
frequencies.
Light key
This key activates the backlight for easier viewing of the display in low-light
conditions. To turn the backlight off, press the key once more.
When the automatic light out function was selected from the menu, the light
will turn itself off automatically after 5 minutes.

7
Controls and Functions
Print key
When the optional printer DPU-414, CP-11, or CP-10 is connected, pressing
this key initiates a printout.
Cal key
Pressing this key activates the built-in oscillator for electrical calibration of
the unit or for level matching of the unit and connected equipment.
Power key
Turns the unit on and off when you hold the key down for more than 1 second.
Hand strap
Attach the carrying strap to the unit as shown below. The strap makes it easier
to carry the unit and serves as a precaution against dropping it. Pass the strap
over your wrist, as shown in the illustration.
U s i n g t h e h a n d s t r a p
C a r r y i n g s t r a p
a t t a c h m e n t n o t c h
C a r r y i n g s t r a p

8
Controls and Functions
Cover
This cover protects the connectors on the bottom during transport or storage.
Removing the cover gives access to the connectors shown above.
External power supply jack
The optional AC adapter NC-98A, NC-34 series can be connected here for
powering the unit from an AC outlet.
Important
To prevent the risk of damage, do not use any AC
adapter other than the specified type.
AC/DC output jack
The signal selected on menu screen 3/5 is output here.
AC: AC signal (with frequency weighting)
DC: DC signal corresponding to sound level
I/O connector
This input/output connector serves for input of control signals and input/output
of measurement data. A printer, level recorder, or computer can be connected
here.
Bottom View
P O W E R
A C D C
O U IO
C o v e r
E x t e r n a l p o w e r s u p p l y a c k
A C / D C o u t p u t a c k
I / O c o n n e c t o r