Center 327 User manual

CENTER 327
Sound Level Calibrator
ANSI S1.40 - 1984
IEC 60942 Class 2
OFF
125Hz
250Hz
Instruction Manual Ver.00 2005/July

1. 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.
2. Description
Sound level calibrator is used to calibrate sound level meters
and other sound measurement equipment. You can calibrate
1” diameter microphones directly and 1/2” microphones using
1/2” adaptor supplied with the calibrator. With available
adaptors, you can calibrate other microphones and
instruments.
3. Features
Conforms to ANSI S1.4-1984 and IEC 60942-2003 Class 2.
94 dB sound calibrator at 125Hz and 250Hz.
Fit 1”and 1/2” diameter microphone.
4. Specifications
Output sound pressure levels:
94dB re 20 uPa under reference conditions
Output frequency: 125Hz +/- 2% and 250Hz +/- 2%
Reference conditions:
Temperature: 23 (74 )℃℉
Relative humidity: 50%
Atmospheric pressure: 1013hpa
Influence of ambient conditions:
Temperature coefficient: 0.005dB/℃
Humidity coefficient: 0.005dB/%RH
Total Harmonic Distortion(THD) : Less than 3%
Accuracy of sound pressure level: +/- 0.5dB
Stabilisation time: 5 sec.
Power: one 9V battery 006P or IEC 6F22 or NEDA 1604
Battery life: approx. 40 hours. ( Alkaline Battery )
Battery test:
Internal circuitry checks condition of battery continuously.
Calibrator will not be operated when green LED turns to red
LED, which means that battery voltage falls bellow acceptable
range.
Dimensions: 113(L)X63(W)X44(H)mm
4.4(L)X2.4(W)X1.7H)inch
Weight: approx. 170g(including battery)
Ambient conditions:
0 – 40 (32℃– 140 ) , 10℉- 90%RH , 650 –1080hpa
Storage temperature & humidity:
-10 – 50 (14℃– 122 ) , 0℉- 70%RH
Accessories:
Instruction manual , carrying case , 9V battery ,
1/2”microphone adapter.
5. Nomenclature and Functions
ANSI S1.40 - 1984
IEC 60942 Class 2
OFF
NEDA 1604
9V BATTERY
6F22 , 006P
1
2
3
4
5
125Hz
250Hz
6. Operating Preparation
1.Remove battery cover and install a 9V battery in the battery
Compartment.
2.To quickly check the operation of the sound level calibrator
Before using it , proceed as follows:
(a) Turn the power switch from OFF to the 94dB position . The
user can start to operate it when LED indicates the green light .
If no, please replace the battery.
(b) Change the switch 125Hz or 250Hz , you can calibrate in
noisy environments and check the frequency response.
7. Calibration Procedure
(1)The cavity of the calibrator will accommodate 1-inch
microphone.
(2)When the calibration is performed to a instrument with
1/2-inch microphone , the 1/2-inch microphone adaptor will
have to be inserted by gently pushing it into the cavity till the
end.
(3)Place the sound level calibrator over the microphone of the
sound measuring instrument being calibrated.
(4)On the instrument under test, set the level range control to the
range having 100dB as its upper limit if 94dB was selected on
the sound level calibrator. The instrument may be set to FAST
or SLOW response.
(5)Read the level on the instrument under test . Sound level
meter will display different reading after selecting different
Frequency weighting , refer to the table below .
Frequency weightings Tolerance limits(dB)
Nominal
frequency LALCLPClass 1 Class 2
1000Hz 94.0 94.0 94.0 ±1.1 ±1.4
250Hz 85.4 94.0 94.0 ±1.4 ±1.9
125Hz 77.9 93.8 94.0 ±1.5 ±2.0
(6)When the calibrator is not in operation, please switch OFF the
power to save the battery.
※CAUTION
Ambient sources of noise or vibration can cause a false calibration
indication, this can be avoided by ensuring surrounds noise/vibration
level is kept at lower than 60 dBA level.
cPower and low battery indicate LED
dPower and output frequency select
switch
eTransducer assembly 1-inch cavity
for microphone insertion
f1/2-inch microphone adapter
gBattery cover