Center C325 User manual

325-01 JAN. 2001

TITLE PAGE
I. Safety Information………………………….1
II. General Description.…………………… 1-2
III. Specifications……………..………………2-3
IV. Name and Functions……………………. 4-5
V. Calibration Procedures………..………...6-7
VI. Measurement Preparation……..……….….7
VII. Operating Precautions………..………….7-8
VIII. Measurement………………………………... 8
C O N T E N T S

SOUND LEVEL METER
1
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

SOUND LEVEL METER
2
RDisplay with 0.1dB steps on a 4-digit LCD.
RTwo equivalent weighted sound pressure levels, A and
C.
RAC signal output is available from standard 3.5mm
coaxial socket suitable for a frequency analyzer, level
recorder, FFT analyzer, graphic recorder , etc.
III. Spe c ifications
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
Med: 50 dB to 100 dB
Hi: 80 dB to 130 dB
Accuracy:

SOUND LEVEL METER
3
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

SOUND LEVEL METER
4
IV. Name And Func t ions

SOUND LEVEL METER
5

SOUND LEVEL METER
6
Output impedance: 100 ohms
Output signal by standard 3.5mm coaxial socket signal
on pin.

SOUND LEVEL METER
7
(1) Make the following switch settings.
Display : dBA
Time Weighting : FAST
Measurement Mode : MAX/MIN Mode function disable.
Level Range : 50 to 100dB
(2) Insert the microphone housing carefully into the
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 . Measurem e nt 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. Ope rat ing Pre c a utions
(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.
(2) Calibrate the instrument before operation if the
instrument was not in use for a long time or operated in
bad environment.

SOUND LEVEL METER
8
(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.