Rion NA-42 User manual

3-20-41 Higashimotomachi, Kokubunji, Tokyo 185-8533, Japan
http://www.rion.co.jp/english/
INSTRUCTION MANUAL
Sound Level Measuring Amplier
NA-42

i
Organization of this manual
This manual describes the features and operation of the Sound Level Measuring
Amplier NA-42.
The manual contains the following sections.
Outline
Gives basic information on the conguration and features of the unit, and
contains a block diagram.
Controls and Features
Briey identies and explains all parts of the unit.
Preparations
Describes installation, connections, inserting batteries, pre-use checks and
other steps.
Measurement
Describes the steps for measurement.
Comparator
Describes how to use the comparator function.
Serial Interface
Describes how to use the serial interface for connection to a computer.
Technical Reference
Provides additional information that is helpful for using the unit.
Specications
Lists the technical specications of the unit.
* Company names and product names mentioned in this manual are usu-
ally trademarks or registered trademarks of their respective owners.

ii

iii
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
injury to persons and/or dam-
age to peripheral equipment.
Disregarding instructions
printed here incurs the risk of
damage to the product.
Mentioned about the tips to
use this unit properly.
(This messages do not have to
do with safety.)
Note

iv
Precautions
Operate the unit only as described in this manual.
Protect 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 lm which can be damaged easily.
Ambient conditions for operation of the unit are as follows: temperature
range -10°C 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.
Always 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.
Before 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 rmly and then use or store the microphone.
Clean the unit only by wiping it with a soft, dry cloth or, when neces-
sary, with a cloth lightly moistened with water. Do not use any solvents,
cleaning alcohol or cleaning agents.
Do not try to disassemble the unit or attempt internal alterations.
In case of an apparent malfunction, do not attempt any repairs. Note the
condition of the unit clearly and contact the supplier.
To ensure continued precision, have the unit checked and serviced at
regular intervals.
Dispose of batteries in accordance with national or local laws and regula-
tions.
Do not tap the LCD panel for example with your nger or a pen, to prevent
possible malfunction or damage.

v
Caution
Some pins of the INPUT connector carry a
high voltage. To prevent the risk of electric
shock, never insert a metal clip or any other
pointed object into the input connector.

vi
Contents
Organization of this manual............................................................ i
FOR SAFETY............................................................................... iii
Precautions.....................................................................................iv
Outline ............................................................................................1
Controls and Features......................................................................4
Front Panel ................................................................................4
Rear Panel ................................................................................8
Display ...................................................................................10
Preparations ..................................................................................13
Power Supply ..........................................................................13
Inserting Batteries ..................................................................13
AC Adapter ............................................................................. 14
Microphone and Preamplier Connection................................15
Calibration...............................................................................20
1) Electrical calibration ......................................................20
2) Calibration with pistonphone NC-72A
or sound calibrator NC-74 ............24
3) Insert CAL calibration ...................................................29
Using a Tripod .........................................................................33
Using a Windscreen.................................................................34
Using the Prop-up Feet ...........................................................35
Measurement ................................................................................36
Power-On.................................................................................36
Level Range Setting.................................................................38
Frequency Weighting Setting...................................................39
Time Weighting Setting ...........................................................40
Lp/ Lmax / Lpeak Setting............................................................41
Low-Pass Filter Setting............................................................44
High-Pass Filter Setting...........................................................45

vii
Bar Graph Display Range (20 dB/50 dB) Setting.....................46
Menu Settings..........................................................................47
External Filter Setting .............................................................52
Backlight On/Off.....................................................................53
Comparator ...................................................................................54
Serial Interface..............................................................................58
Transfer Protocol ....................................................................58
Local Mode/Remote Mode .....................................................59
Transfer Sequence ................................................................... 61
Error Processing .....................................................................63
Control Operation in Remote Mode ........................................63
Command Format ...................................................................64
Commands ..............................................................................67
Technical Reference ......................................................................81
Microphone and Preamplier Selection ...................................81
Microphone .............................................................................85
Preamplier .............................................................................88
Insert CAL...............................................................................89
Extension Cable .......................................................................90
Windscreen..............................................................................92
Inuence of Background Noise................................................94
Frequency Weighting ...............................................................95
INPUT Connector....................................................................96
RMS Detection Circuit and Time Weightings..........................97
Factory Default Settings ........................................................100
Displaying the Software Version............................................ 101
Rack Mounting ...................................................................... 101
NA-42PB1 ............................................................................. 102
Specications ..............................................................................104

viii

1
Outline
The NA-42 is a sound level measuring amplier covering a wide frequency
range and level range. It allows connection of various types of microphones
such as the low-noise microphone UC-34P or the 100-kHz range microphone
UC-29.
For general acoustic measurements and for environmental measurements,
selectable frequency weightings (A, C, and FLAT) and time weightings
(FAST, SLOW, IMPULSE) are provided. Other measurement modes allow
determining maximum values for sound level, as well as peak sound level.
Measurement result readout resolution can be switched to one or two decimal
points, and the large LCD panel shows setting information as well.
The choice of outputs includes AC, DC, serial interface, as well as a compara-
tor output, making the unit suitable for use in a wide range of measurement
and monitoring applications.
The unit uses a box-type design that makes it easily portable. Because it can
be powered from the supplied AC adapter or from batteries, it is suitable for
use in the eld or in research facilities.

2
Outline
Main Unit Block Diagram
OVER
OVER OVER
OVER
OVER
TO
FILTER
FROM
FILTER
AC OUT
DC OUT
A
C
FLAT
A, C
FLAT
AMP
AMP A/D
OVER ROM CPU DSP ROM
I/O EEP
ROM
D/A AMP
AMP
ATT
-20 dB
AMP
+10 dB
AMP
+20 dB
AMP
+10 dB
AMP
+20 dB
AMP
+10 dB
LCD
DRIVER
HPF
20 Hz
LPF
20 kHz
ATT
-10 dB
AMP
CAL ADJ
Antialiasing filter
Connector E
Input CAL signal
External
filter
Microphone bias voltage
Power
supply
circuit
Analog circuitry
drive voltage
Digital circuitry
drive voltage
AC adapter
Batteries
Power supply
voltage monitoring
Serial interface LCD
(display)
CAL signal

3
Outline
Main Unit Gain Diagram
140
130
120
110
100
90
80
70
ATT
0dB
-10 dB
-20 dB
AMP
0dB
+10 dB
+20 dB
AMP
0dB
+10 dB
+20 dB
AMP
0dB
+10 dB
Example: Sensitivity
-29.9 to -20.0
Level range (dB)
Adjustment by CAL ADJ
(Span of adjustable range: 10 dB)

4
Controls and Features
Front Panel
LEVEL RANGE keys
Serve to shift the range up or down. The key switches the range up,
and the key switches the range down. When the PREAMP power
selector on the rear panel of the unit is set to ±45V, these keys are dis-
abled (page 38).
20 dB/50 dB key
Toggles the bar graph display range between 20 and 50 dB.
CAL key
Activates the built-in oscillator for electrical calibration.
SOUND LEVEL
MEASURING AMPLIFIER
HPF LPF
LEVEL RANGE
CAL
20dB/50dB
POWER
EXT FILTER
RESET
L
p/
L
max
/
L
peak ON
INPUT
NA-42
ADJ
FAST
SENS
MENU 20Hz 20kHz
A/C
/FLAT /SLOW
/IMP
(LIGHT)
LEVEL RANGE key
20 dB/50dB key
CAL key
FAST/SLOW/IMP key
Sensitivity control
20 kHz key
POWER switch
EXT FILTER key
RESET key
20 Hz key
Lp/Lmax/Lpeak key
MENU (LIGHT) key
Handle
A/C/FLAT key
INPUT connector
Setting up/down
keys
SENS key
Display

5
Controls and Features
FAST/SLOW/IMP key
Selects the time weightings. Available settings are FAST, SLOW, and
IMP (IMPULSE).
Sensitivity control
Serves to adjust the unit to match the microphone sensitivity.
20 kHz key
Switches the low-pass lter (LPF) on and off. When the lter is on, sig-
nal components 20 kHz or above are sharply attenuated.
POWER switch
Turns the unit on and off.
EXT FILTER key
Switches an external lter on and off.
RESET key
The function of this key depends on the current operation mode of the
unit.
• When set to maximum sound level (Lmax)
Resets the currently held measurement value.
• When set to peak sound level (Lpeak)
Resets the currently held measurement value.
• During remote operation via serial interface
Terminates remote operation and switches the unit to local
mode.
• When power is off
Switching power on while holding down the RESET key returns
the unit to the factory default settings (except for the setting of the
PREAMP power selector on the rear panel and the microphone
sensitivity setting).

6
Controls and Features
20 Hz key
Switches the high-pass lter (HPF) on and off. When the lter is on,
signal components 20 Hz or below are sharply attenuated.
Lp/Lmax/Lpeak key
Switches the measurement mode to sound level Lp, maximum sound
level Lmax, or peak sound level Lpeak.
MENU (LIGHT) key
Pressing this key brings up the menu. Use the setting up/down keys to
make a selection.
Holding down the MENU (LIGHT) key for at least 2 seconds switches
the display backlight on or off. When the unit is running on batteries,
the backlight is automatically turned off after 10 minutes.
Switching power on while holding down the MENU (LIGHT) key calls
up the software version.
INPUT connector
The microphone preamplier is connected here. The sensitivity of the
unit must be adjusted to match the microphone sensitivity.
The connector is a 7-pin connector (TAJIMI ELECTRONICS CO., LTD.).
A: Preamplier power supply +12 V or +45 V
B: Ground
C: Signal input
D: Preamplier power supply -12 V or -45 V
E: 30 V DC Microphone bias voltage
(when preamplier gain is set to 20 dB)
Ground When preamplier gain is set to 0 dB
Calibration signal output When INSERT CAL is selected
F: 60 V DC Microphone bias voltage
G: 200 V DC Microphone bias voltage

7
Controls and Features
Caution
To prevent the risk of electric shock, never
insert a metal clip or any other pointed object
into the input connector.
Setting up/down keys
These keys are used for setting the microphone sensitivity or for mak-
ing a selection from a menu.
SENS key
Pressing this key activates the mode for setting the microphone sensi-
tivity. The setting range is -69.99 to -10.00 dB. Use the setting up/down
keys to adjust the setting.
The setting resolution is one decimal point when the readout resolution
is set to 0.1 dB and two decimal points when the readout resolution is
set to 0.01 dB.
A/C/FLAT key
This key selects the frequency weightings. Available settings are A
weighting, C weighting, and at response.
Display
Shows measurement values and key setting information.
Handle
Serves for carrying the unit. Allowable weight is 250 N.

8
Controls and Features
Rear Panel
Battery holder
Four IEC R14 (size "C") batteries can be inserted here.
Battery holder button
Pressing this button sets the lid lock to on or off.
AC OUT connector
An AC signal corresponding to the measured value is supplied at this
connector.
The scale range is 1 Vrms, and output impedance is 600 Ω.
DC OUT connector
A DC signal corresponding to the measured value is supplied at this
connector.
The scale range is 6 V (1 V/10 dB), and output impedance is 50 Ω.
SERIAL COMP OUT
±12V ±45V
PREAMP
ACOM
LOCK UNLOCK
BATT BOX
AC OUT
DC OUT
EXT 6V
TO
FILTER
FROM
FILTER
EXT
FILTER
Battery holder
Battery holder button
AC OUT connector
DC OUT connector
Name plate
External power supply
connector
Comparator output
PREAMP power selector
SERIAL interface connector
External filter connectors

9
Controls and Features
Name plate
The serial number of the unit is shown here.
External power supply connector
The dedicated AC adapter (NC-98C) is connected here.
Comparator output
This is an open-collector output with an A contact and COM contact.
PREAMP power selector
Selects ±12 V or ±45 V as power supply voltage for a connected pream-
plier. The default setting is ±12 V.
Preampliers compatible with both ±12 V and ±45 V
NH-01, NH-04, NH-05, NH-11, NH-12, NH-14, NH-16, NH-17, NH-
17A, NH-19, NH-20, NH-28
Preampliers compatible only with ±12 V (do not set to ±45 V)
UC-34P (NH-34), UC-24, UC-91, UC-92
SERIAL interface connector
This D-sub 9-pin male connector is for the built-in serial interface.
External lter connectors
Allow connection of an external lter to the unit.

10
Controls and Features
Display
COMP
Appears when the comparator function is activated.
The comparator function can be selected from a menu.
REMOTE
Appears when the unit is in the remote mode (page 59).
OVER
Appears when the input signal has exceeded the overload threshold.
When this happens, correct measurement is not possible.
Calibration value
During calibration, the calibration value is shown here. The value is 6
dB below the level range maximum. In other operation modes, the indi-
cation "P20" is shown here if preamplier gain was set to 20 dB with a
menu selection (Using UC-34P).
Level range
Shows the selected level range.
COMP REMOTE
OVER
UNDER CAL
PEAK MAX OVER
FAST SLOW IMP
Hz kHz
INSERT
UNDER
INSERT
CAL
COMP
REMOTE
OVER
PEAK MAX OVER
HPF LPF
EXT
EXT
AC
FLAT
Calibration value
Level range (upper limit)
Bar graph indicator
Units
Frequency weighting
Time weighting
Level range
(lower limit)
Battery indicator
M
easurement value
r
eadout