ATP Electronics ET-933 User manual

User Manual
Professional Sound Level Meter
Please read this user manual thoroughly before using
this unit and keep it for your future reference.

Contents
1. Safety..................................................................1
2. Applications and Features...................................2
3. Specifications......................................................3
4. Meter Description................................................4
5. LCD Display Description.....................................5
6. Operation Instruction...........................................6
7. Calibration...........................................................9
8. Basic Operation.................................................10
9. Notes.................................................................11
10. Accessories.....................................................12

1
1. Safety
Read the following safety information carefully before
attempting to operate the meter.
Use the meter only as specified in this manual; otherwise,
the warranty may be invalidated.
◆Environment conditions:
Altitude up to 2000 meters
RH≤90％（Non-Condensation）
Operating Temperature: -20°C ～60°C
◆Maintenance
Repairs or servicing should only be performed by ATP
Instrumentation Ltd.
Cleaning: Wipe the unit with a dry soft cloth. Do not use
abrasives or solvents on this instrument.
◆Safety Symbol
Complies with EMC

2
2. Applications and Features
This Sound Level Meter is designed to meet the
measurement requirements of safety engineers, health and
safety legislation, industrial safety officers and sound quality
control in various environments like factories, schools,
construction sites etc.
◆
◆Max/Min/Data Hold
◆Over-range indication
◆Under-range indication
◆A & C Weighting
◆FAST & SLOW response

3
3. Specifications
Applied standard
Frequency range 31.5Hz～8kHz
Dynamic range 50dB
Measuring level
range
Lo：30dB～80dB Med：50dB～100dB
Hi：80dB～130dB Auto：30dB～130dB
Accuracy ±1.4dB
Time weighting FAST: 125ms – SLOW: 1s
Microphone 1/2 inch electret condenser microphone
Display 3½ digits LCD display with a resolution of 0.1dB
Frequency weighting A & C
Data update 2 times per second
Alarm function “OVER” – input is more than upper range limit.
“UNDER” – input is less than lower range limit.
Auto power off Meter automatically shuts down after approx. 15
minutes inactivity.
Power supply 1x 9V battery, 006P or IEC 6F22 or NEDA 1604.
Battery life at least 30 hours
Operating conditions -20
℃
～60
℃
，10％RH～90％RH
Storage conditions -20
℃
～60
℃
，10％RH～75％RH
Weight 178g
Dimension(L*W*H) 158 x 62 x 32mm

4
4. Meter Description
①Microphone ②LCD display
③Frequency weighting A/C selection key
④MAX/MIN Key
⑤Range Level selection key
⑥Response time FAST/SLOW selection key
⑦Power ON/OFF key ⑧Battery Compartment

5
5. LCD Display Description
①Under-range icon
②MAX hold
③Min hold
④Fast sampling time icon
⑤Slow sampling time icon
⑥Over-range icon
⑦Level range display
⑧Analog bar
⑨Measurement reading
⑩Battery icon
⑪Auto range icon
⑫Data hold icon
⑬dBC icon
⑭dBA icon
⑮Auto power off icon

6
6. Operation Instruction
(1) Power ON/OFF: Turn the meter on by pressing the
" " button for 1 second. To turn the meter off, press and
hold the " " button for approx. 3 seconds then release the
button.
(2) Backlight:
After turning the meter on, momentarily press the " " key,
the backlight will turn on/off. It will automatically turn off after
approx. 30 seconds of inactivity.
(3) Frequency weighting A/C selection:
Press " " key to select Aor C.
dBA: “A“ frequency weighting (designed to reflect the
response of the human ear to noise which is most sensitive
between 500Hz and 6000Hz)
dBC: “C” frequency weighting (commonly used to measure
peak sound pressure levels)

7
(4) FAST/SLOW selection
With the meter powered on; press the “ ” button to select
FAST or SLOW measurement mode.
FAST: Fast sampling time measurement, 1 time per 125ms.
SLOW: Slow sampling time measurement, 1 time per
second.
(5) MAX/MIN
With the meter powered on, press and hold the " "
button for 3 seconds to enter MAX measurement. After 3
seconds, release the button while the flashing ‘MAX’ icon
appears on the LCD. The maximum measured value will be
displayed. Press the button again to alternate back and forth
between ‘MIN’ and ‘MAX’ modes. Press and hold the button
for 3 seconds to exit MAX/MIN measurement mode.

8
(6) Data HOLD:
After turning the meter on, momentarily press the " "
button. "HOLD" icon will appear on the LCD, which indicates
the data is frozen. To release the held reading, press the
button again.
(7) Level range selection:
Press the “ ” key and the level range will change from
‘Lo’, ‘Med’, ‘Hi’ to ‘Auto’ in turn.
Lo：30dB～80dB Med：50dB～100dB
Hi：80dB～130dB Auto：30dB～130dB

9
7. Calibration
The recommended recalibration period is 1 year.
Calibration, repairs or servicing should only be performed by
ATP Instrumentation Ltd.

10
8. Basic Operation
(1) Open battery cover and install a 9-volt battery in the
battery compartment.
(2) Press the ‘ ’ button to select desired level range.
(3) Select ‘dBA’ for general noise sound levels or ‘dBC’ for
measuring peak sound levels.
(4) Select ‘FAST’ for instant response or ‘SLOW’ for an
average sound level over 1 second.
(5) Select the ‘ ’ button to view the maximum and
minimum noise level readings.
(6) Hold the meter in hand or use the tripod to affix the
meter in the desired location. The best measuring distance is
1m to 1.5m away from the sound source to the microphone.

11
9. Notes
(1) Do not store or operate the meter in high temperature or
humidity.
(2) Remove the battery when the meter is to be stored for
long periods of time to avoid battery leakage.
(3) Wind blowing across the microphone will affect the noise
measurement. Use the supplied wind muffler to cover the
microphone during applications involving turbulent air.
(4) Keep microphone dry and avoid severe vibration.
(5) If the date and time automatically reset to the default
setting after powering the meter on, this indicates the battery
power is low. The meters’ battery should then be replaced.
(6) When the low battery icon " " appears, replace the
meters’ battery.

12
10. Accessories
①User Manual
②Wind Muffler
③Regulator Rod
④9V battery

ATP Instrumentation Ltd
Tournament Way
Ashby-de-la-Zouch
Leicestershire
LE65 2UU
Sales: 01530 566 800 [e-mail]
Repair and Calibration: 01530 566 804 [e-mail]
www.atp-instrumentation.co.uk