Center 32 Instruction Manual

32

SOUND LEVEL METER

CENTER TECHNOLOGY CORP.

4F, NO.415, Jung-Jeng Rd., Shu-Lin Dist., New Taipei City 238, Taiwan
E-Mail:[e-mail]
http://www.centertek.com

GCA 00003 2-020 00

Safety Information

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Environment Conditions:

Introduction

This Sound Level Meter has been designed to meet the measurement
requirements of safety Engineers, Health, Industrial safety offices and
sound quality control in various environments.

Both AC and DC signal outputs are available from standard 3.5mm coaxial
socket, suitable for a frequency analyzer, level recorder, FFT analyzer,
graphic recorder, etc.

Read the following safety information carefully before attempting to operate
or service the meter.

Use the meter only as specified in this manual; otherwise, the protection
provided by the meter may be impaired.

Ÿ Altitude up to 2000 meters
Ÿ Relatively humidity 90% max.

Ÿ Operation Ambient 0 ~ 40°C

Explanation of Symbols:

Attention! Refer to operation instructions.

Comply with EMC.
When servicing, use only specified replacement parts.

Operation Temperature:
Operation Humidity:
Storage Temperature:

Dimension / Weight:
Accessories:

0 to 40°C (32 to 104°F)

10 to 90%RH

258 55 10.2” 2.2”× ×25mm ( × ×1.0”) / Approx. 185g
battery, Instruction manual, Windscreen, Tool box.

-10 to 60°C (14 to 140°F)

Measurement Preparation

Remove the battery
cover on the back and
insert a 9V Battery.

2. Battery Loading:

Repairs or servicing not covered in this manual should only be performed
by qualified personnel.

Attention!

Periodically wipe the case with a dry cloth. Do not use abrasives or
solvents on this instrument.

Cleaning

Digital Display:

4 digits

Analog display: 30 segment bargraph

Time weighting: FAST , SLOW

Resolution: 0.1dB
Display updata: 0.5 sec.

Resolution: 2dB
Display updata: 100 mS

Level ranges: Lo: 30 - 90 dB

Accuracy: ±1.4dB (under reference conditions)

Med: 50 - 110 dB
Hi: 70 – 130 dB

Dynamic Range: 60 dB
Alarm Function: “ ” is show when input is more than upper

limit of range.
“ ” is show when input is Less than lower limit

of range.

AC Output: 1 Vrms at FS (full scale)

FS: means the upper limit of each level Range.

DC Output: 10mV / dB
Power Supply: One 9V battery, 006P or IEC 6F22 or NEDA 1604
Power Life: Approx. 60hrs (alkaline Battery)

Storage Humidity:

10 to 75%RH

Maintenance

When operating the unit on battery, periodically check this indicator to
determine the remaining battery capacity.

1. Battery capacity indicator:

Batteries Good

Batteries Partly
Depleted

Replace Batteries

9V battery

Specifications

Standard Applied:

Frequency Range:

IEC61672-1 Class2

20Hz ~ 8KHz
Measuring level Range: 32 ~ 130dB
Frequency Weighting: A / C
Microphone: ½ inch electret condenser microphone

Calibration Procedures

(1) Press and hold button and then power on

the meter, LCD display “CAL 94dB” symbol.

(2.) Insert the microphone housing carefully into the

insertion hole of the calibrator.

(3.) Press or button to increase or decrease

number.

(4.) Press button to finish. To abort during a

setup process, press power button to cancel.

Note: Our products are all well calibrated before
shipment.
Recommended recalibration cycle: 1 year.

Using a standard Acoustic Calibrator

(94dB, 1KHz Sine wave )

2. LCD Display:

A-Weighting ind icator

Batter y capacit y indicator

C-Weighting ind icator

Readin g indicat or

Range In dicator

Under ra nge indic ator

Auto pow er off indi cator

Calibr ation Mod e indicator

Over ran ge indica tor

Slow res ponse ind icator

Maximu m/Minim um
Valu e hold indicat or

Fast res ponse ind icator

Time weighting select Switch:
FAST: for normal measurements
SLOW: for checking average level of fluctuating noise.
Microphone:
1/2 inch Electret Condenser microphone.

AC／DC output terminal:

AC Output: 1 Vrms corresponding to each range step.
DC Output: 10mV/dB.

Tripod mounting screw
Battery Cover

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Symbol Definition & Button Location

1. Name of Parts & Position:

Windscreen.
Display: 4 digits LCD display
Power Switch:

The key turns the sound level meter ON.
Press and hold this button for 2 seconds to turn OFF the power.

Auto Power Off:
By default, when the meter is powered on, it is under auto power off

mode. The meter will power itself off after 30 minutes if no key
operation.

One may press and hold “ ” button and then power on the meter
and the will not show up to indicate that auto power off is disabled.

Level range control button:
Each time the button is pressed. The level range increments from

“ Lo ” Level to “ Hi ” Level range.
Level range control button:
Each time the button is pressed. The range decreases from “ Hi ”

Level to “ Lo “ Level range.
Frequency Weighting select switch:
A: A - Weighting. for general sound level measurements.
C: C - Weighting. for checking the low-frequency content of noise.
(If the C-Weighted level is much higher than the A-weighted level, then

there is a large amount of low-frequency noise.)
MAX / MIN hold switch:
Press button to enter the maximum and minimum recording mode.

Select the proper Level range before using MAX/MIN to ensure that
reading value will not exceed the measurement range. Press once to
select MAX value. Press again to select MIN value, and press again to
select current value with “ MAX MIN “ annunciator blinking.

Press and hold down button for 2 seconds to exit the MAX.MIN
mode.

Note: If change sound level range or change A-C weight, the
MAX.MIN mode will be cleared.

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Measurement

(1) Turn on and select the desired response time and weighting. If the

sound source consists of short bursts, set response to FAST. To
measure average sound level, use the SLOW setting.

Select A weighting for general noise sound level and C weighting for

measuring sound level of acoustic material.
(2) Select desired Level.
(3) Hold the instrument comfortably in hand or fix on tripod and point the

microphone at the suspected noise source, the sound pressure level
will be displayed.

(4) When MAX MIN (maximum, minimum hold) mode is chosen. The

instrument captures and holds the maximum and minimum noise level
for a long period using any of the time weightings and ranges.

Press the button 2 seconds to clear the MAX/MIN reading.
“ / ” symbol disappears.

(5) Turn OFF the instrument.

Operating Precautions

(1) Wind blowing across the microphone would bring additional

extraneous noise.

Once using the instrument in the presence of wind, it is a must to

mount the windscreen to avoid picking up undesirable signals.
(2) To achieve more accurate measurement, use an extension cable to

separate the microphone from the main body so that the effect of
unexpected sound reflection can be eliminated.

(3) Calibrate the instrument before operation if the instrument was not in

use for a long time or operated at bad environment.

(4) Do not store or operate the instrument at high temperature and high

humidity environment.
(5) Keep microphone dry and avoid severe vibration.
(6) Please take out the battery and keep the instrument in low humidity

environment when not in use.