UT351 Digital Sound Level Meter

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Product Information

Specifications

• Accuracy: 1.5 dB (under reference conditions)

• Frequency range: 31.5KHz to 8.5KHz

• Linearity range: 50dB

• Measuring level: 30-130 dBA, 35-130 dBC

• Frequency weighting: A, C

• Digital display: 5 digits Resolution: 0.1dB

• Bar graph: 50dB scale at 1 dB step for monitoring current sound
  pressure level display period: 50 mS

• Level ranges: 30-80 dB, 50-100 dB, 60-110 dB, 80-130 dB

• Over range indicator

• AC output: 0.707 Vrms at FS output impedance approx 600

• DC output: 10 mV / dB output impedance approx 1000

• Time weighting: Fast, Slow

• Microphone: 1/2 inch Electret Condenser microphone

• Max: Maximum hold

• Power supply: 1 *9V alkaline cells or DC 9V adapter Power life:
  About 30 hrs (alkaline coils)

• Self calibration time: 10 sec (every turn on)

• Operating Temperature: 0C to 40C, Operating Humidity: 10% to
  80% RH

• Storage Temperature: -10C to 60C, Storage Humidity: 10% to
  70%RH

• Dimensions: 265(L)72(W)35 (H) mm

• Weight: 300g (including batteries)

Product Usage Instructions

Calibration Procedures

Use a Standard Acoustic Calibrator.

1. Use the following settings:

   • Display: SPL (dBA)

   • Time Weighting: FAST

   • Level range: 60 to 110 dB / 80 to 130dB (depending on
     calibrator type)

   • Measurement mode: MAX function disable

2. Insert the microphone carefully into the 1/2 inch hole of the
   Calibrator.

3. Turn on the Calibrator and adjust the Potentiometer inside the
   Battery compartment of the unit. The level display will indicate
   the desired Level (94.0).

Name and Functions

1. Electric Condenser Microphone.
2. LCD Display.
3. Power switch.
4. Level range control switch.

LCD Display Description

1. Level range.
2. Instantaneous sound pressure level.
3. Low battery mark.
4. Maximum value is held during measurement.
5. Measured value.
6. Measurement Unit.
7. Frequency weighting A/C.
8. Level range Bar graph.
9. Over Range Indicator.
10. Slow time weighting.
11. Fast time weighting.
12. Under Range Indicator.

Pre-operation

1. Use a Screwdriver to open the battery door and install four 9V
   batteries in the battery compartment.

2. Install the battery door with a Screwdriver.

3. When the battery voltage drops below the operating voltage, a
   symbol appears, please replace it with a new one.

Frequently Asked Questions (FAQ)

Q: What is the recommended recalibration period for the

product?

A: The recommended recalibration period is once a year.

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User Manual
Version 1.1
AUTOTESTTM
Digital sound level meter

A. Precautions:
Please read this operation manual carefully before using this equipment for correct operations. This equipment has been designed to meet the measurement requirement of Safety Engineers, Health, Industrial Safety offices and Sound Quality control in various environments.
B. Features:

1. This unit was designed according to the IEC651 TYPE 2 & ANSI S 1 .4 TYPE 2 for sound level meters. 2) Instantaneous level measurement. 3) Measurement range: 30-130 decibel 4) With two equivalent weighted sound pressure levels, A and C. 5) Fast & Slow modes. 6) AC and DC signal output for frequency analyzer and level recorder, FFT analyzer, graphic recorder etc.
   C. Specifications:

2. Accuracy: 1.5 dB (under reference conditions) 2) Frequency range; 31.5KHz 8.5KHz 3) Linearity range: 50dB 4) Measuring level: 30 130 dBA, 35-130 dBC 5) Frequency weighting:. A, C 6) Digital display: 5 digits Resolution: 0.1dB 7) Bar graph; 50dB scale at 1 dB step for monitoring current sound pressure level display period: 50 mS 8) level ranges: 30-80 dB: 50-100 dB;
   60-110 dB; 80-130 dB; 9) Over range indicator:
   Under indicator. 10) AC output: 0.707 Vrms at FS output impendence approx 600

3. DC output: 10 mV / dB output impedance approx 1000 12) Time weighting: Fast, Slow 13) Microphone: 1/2 inch Electret Condenser microphone 14) Max: Maximum hold 15) Power supply: 1 *9V alkaline cells or DC 9V adapter Power life: About 30 hrs (alkaline coils)
   -2-

4. Self calibration time: 10 sec (every turn on) 17) Operating Temperature: 0C to 40C
   Operating Humidity: 10% to 80% RH I8) Storage Temperature: – I0C to 60C
   Storage Humidity: 10% to 70%RH 19) Dimensions: 265(L)72(W)35 (H) mm 20) Weight: 300g (including batteries)
   D. Calibration Procedures:
   Use a Standard Acoustic Calibrator. 1) Use the following settings:
   Display: SPL (dBA) Time Weighting: FAST Level range: 60 to 110 dB / 80 to 130dB (depending on calibrator type) Measurement mode: MAX function disable 2) Insert the microphone carefully into the 1/2 inch hole of the Calibrator. 3) Turn on the Calibrator and adjust the Potentiometer inside the Battery compartment of the unit (shown in the diagram 1). The level of the unit (shown in figure 1). The level display will indicate the desired Level (94.0).
   Recommended recalibration period: 1 year.
   Figure 1.
   -3 –

E. Name and Functions:

1. Electric Condenser Microphone. 2) LCD Display. 3) Power switch 4) Level range control switch;
   30dB–80dB; 50dB–l00dB; 60dB–10dB; 80dB–l30dB 5) Maximum value hold switch. (MAX) 6) Frequency weighting select switch. A: A weighting for general sound level measurements. C: C- weighting for checking the low frequency content of noise. 7) Time weighting select switch. Fast: For normal measurements. Slow: For checking average level of fluctuating noise. 8) AC output terminal: 0.707 Vrms Corresponding to each range step. 9) DC output terminal: output 10 mV/ dB
2. Calibration control 11) External DC 9V power supply terminal. 12) Battery Door. 13) Tripod mounting screw. 14) Windscreen
   -4-

F. LCD Display Description:

1. Level range. 2) Instantaneous sound pressure level. 3) Low battery mark. 4) Maximum value is held during measurement. 5) Measured value. 6) Measurement Unit. 7) Frequency weighting A/C. 8) Level range Bar graph. 9) Over Range Indicator. 10) Slow time weighting. 11) Fast time weighting. 12) Under Range Indicator.
   Figure 3
   -5-

G. Pre-operation:

1. Use a Screwdriver to open the battery door and install four 9V battery in the battery compartment. 2) Install battery door with Screwdriver. 3) When the battery voltage drops below the operating voltage, a

symbol

appears, please replaced with a new one.

4. When the DC adapter is used, insert the plugs (3.5) of the adapter into the DC 9V connector on the side panel.

H. Operation:

1. Turn on power 2) Select the desired response and weighting, also select desired range. 3) If weighting for general noise sound level, please select dBA. 4) If the sound source consists of short bursts, set response to FAST.
   To measure the average sound level, use the SLOW setting. 5) When the MAX mode is chosen the instrument will capture and hold the maximum noise level.
   -6-

I. Cautions

1. Do not operate the unit in an environment of high temperature and humidity.
2. Please take the battery out from the unit if not in use for any extended period of time. 3) When using the unit in the presence of wind, it is recommended to fit the windscreen to avoid undesired signals. 4) Operating Environmental condition:
   Humidity 80%RH, Temperature from 0°C to 40°C.
   -7-

AUTO TEST Products Pty Ltd. 69 Parsons st. Kensington, VIC 3031 Australia
Enquiries: (+61 3) 8840 3000 Service: (+61 3 8840 3016 Sales: (+61 3) 8840 3017 Fax: (+61 3) 8840 3099 Email: service@autotest.net.au sales@autotest.net.au info@autotest.net.au www.autotest.net.au

References

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