CONTENTS
TITLE PAGE
I.
Safety Information……………………………1
II.
General Description………………………… 1
III. Specifications…..…………....………………2
IV.
Name and Functions…………………….…4
V.
Calibration Procedures………..………..…6
VI.
Measurement Preparation……..……….…. 7
VII.
Operating Precautions………..……...……7
VIII. Measurement……………………………...
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I. Safety Information
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.
Environment Conditions
Altitude up to 2000 meters
Relative humidity 90% max.
Operation Ambient 0 to 40℃
Maintenance & Clearing
Repairs or servicing not covered in this manual should
only be performed by qualified personnel.
Periodically wipe the case with a dry cloth. Do not use
abrasives or solvents on this instrument.
Safety symbols
Comply with EMC
When servicing, use only specified replacement
parts.
II. General Description
Thank you for using our Sound Level Meter. To ensure that
you can get the most from it, we recommend that you read
and follow the manual carefully before use.
This unit conforms to the IEC651 type2, ANSI S1.4 Type2
for Sound Level Meters.
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.
Range from 32dB to 130dB at frequencies between
31.5Hz and 8 KHz.
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Display with 0.1dB steps on a 4-digit LCD.
Two equivalent weighted sound pressure levels, A and
C.
AC signal output is available from standard 3.5mm
coaxial socket suitable for a frequency analyzer, level
recorder, FFT analyzer, graphic recorder, etc.
III. Specifications
Standard Applied: IEC651 Type2, ANSI S1.4 Type2.
Frequency Range: 31.5Hz to 8KHz
Measuring Level Range: 32dB to 130dB
Frequency Weighting: A / C
Microphone: 1/2 inch electret condenser microphone
Display: LCD
Digital Display: 4 digit
Resolution: 0.1dB
Display Update: 0.5 sec.
Time Weighting: FAST ( 125mS ), SLOW ( 1 sec. )
Level Ranges: Lo: 32 dB to 80 dB
Accuracy:
±1.5dB ( under reference conditions, 94dB@1kHz )
Dynamic Range: 50 dB
Alarm Function: “OVER” is when input is more than
MAX / MIN Hold:
Hold readings the Maximum and Minimum Value.
Med: 50 dB to 100 dB
Hi: 80 dB to 130 dB
upper limit of range.
“UNDER” is when input is less
than lower limit of range.
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AC Output: 1 Vrms at FS ( full scale ).
Output impedance: Approx. 100 Ohms
FS: means the upper limit of each level range.
Electromagnetic Compatibility:
RF field = 3V/m
Total accuracy = specified accuracy + 0.5dB
Power Supply:
One 9V battery, 006P or IEC 6F22 or NEDA 1604.
Power Life: Approximately 70hours ( alkaline battery )
Operation Temperature: 0 to 40℃ ( 32 to 104℉ )
Operation Humidity: 10 to 90%RH
Storage Temperature: -10 to 60℃ ( 14 to 140℉ )
Storage Humidity: 10 to 75%RH
Dimensions: 9.1” L ×2.1” W ×1.3” H
Weight: 170kg (0.37 lbs) ( including battery )
Accessories: 9V battery, instruction manual, screwdriver,
23.1 cm ×5.3 cm ×3.3 cm
and windscreen.
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IV. Name and Functions
KEW325
1
Windscreen
○
If you operate at wind speed over 10m/sec, please put
protective accessories in front of the microphone.
2
Display
○
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○3 Power Button
I
The ○
key turns the sound level meter ON or OFF.
4
MAX / MIN Hold button
○
5
○
6
○
7
○
8
○
9
○
MAX
Press button to enter the maximum and minimum
MIN
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.
MAX
Press and hold down button for 2 seconds to exit
MIN
the MAX/MIN mode.
Note: If change sound level range or change A-C
weight, the MAX.MIN mode will clear.
Frequency Weighting Select Button
A: A - Weighting. for general sound level measurements.
C - Weighting. for checking the low-frequency content
C:
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 )
Time Weighting Select Button.
FAST: for normal measurements
SLOW: for checking average level of fluctuating noise.
Level Range Control Button
Each time the level button is pressed, the level range
will change between “Lo” level, “Med” level and “Hi”
level in the circular manner.
Microphone
1/2 inch Electret Condenser microphone
AC Output Terminal
1 Vrms Corresponding to each range step.
5
Output impedance: 100 ohms
Output signal by standard 3.5mm coaxial socket signal
on pin.
10
CAL Potentiometer
○
Calibration control, for level calibration adjustment.
11
○
Battery Cover
V.
Calibration Procedures
Using a standard Acoustic Calibrator
(94dB, 1KHz Sinewave)
KEW325
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(1) Make the following switch settings.
Display: dBA
Time Weighting: FAST
Measurement Mode: MAX/MIN Mode function disable.
Level Range: 50 to 100dB
Insert the microphone housing carefully into the
(2)
insertion hole of the calibrator.
(3) Turn on the switch of calibrator and adjust the CAL
potentiometer of the unit. The level display will indicate
the desired level.
All our products are well calibrated before shipment.
Recommended Recalibration cycle: 1 year.
VI. Measurement Preparation
(1) Battery Loading
Remove the battery cover on the back and put in one
9V Battery.
(2) Battery Replacement
When the battery voltage drops below the operating
voltage, this symbol will appear.
Replace 9 Volt battery.
VII. Operating Precautions
(1) Wind blowing across the microphone will bring
additional extraneous noise.
When using the instrument in the presence of wind, it
is a must to mount the windscreen to not pick up
undesired signals.
Calibrate the instrument before operation if the
(2)
instrument was not in use for a long time or operated in
bad environment.
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(3) Do not store or operate the instrument at high
temperature and high humidity environment.
(4) Keep microphone dry and avoid severe vibration.
(5) Please take out the battery and keep the instrument in
low humidity environment when not in use.
VIII. Measurement
(1) Open battery cover and install a 9V battery in the
battery compartment.
(2) Turn power ON and select the desired response time
and weighting. If the sound source consists of short
bursts or only catching sound peak, 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.
(3) Select desired Level.
(4) Hold the instrument comfortably in hand and point the
microphone at the suspected noise source, the sound
pressure level will be displayed.
(5) 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 MAX/MIN button 2 seconds to clear the
MAX/MIN reading. “ MAX/MIN ” symbol disappears.
(6) Turn OFF the instrument.
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GCBKEW325-02000
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