UNI-T UT351, 352 Sound Level Meter Instruction Manual

UNI-T UT351, 352 Sound Level Meter

Overview

The Sound Level Meter Model UT351 and UT352 (hereafter referred to as the Meter) is a stable, safe, and reliable sound level meter. The Meter is suitable for use in noise control, quality control, health care, and all different kinds of environmental noise testing. For example, factories, roads, families, musical instruments, and all kinds of places that need noise testing.

Unpacking Inspection

Open the package case and take out the Meter. Check the following items carefully to see any missing or damaged parts:

In the event you find any missing or damaged, please contact your dealer immediately.

Rules For Safe Operation

1. Soft cloth and mild detergent should be used to clean the surface of the Meter when servicing. No abrasive and solvent should be used to prevent the surface of the Meter from corrosion, damage, and accident.
2. Constantly check the battery as it may leak when it has been used for some time, and replace the battery as soon as leaking appears. A leaking battery will damage the Meter.

International Electrical Symbols

Conforms to Standards of the European Union

The Meter Structure (see Figure 1)

1. Housing
2. Windscreen
3. Microphone
4. LCD Display
5. Functional Buttons
6. Signal output and power terminals

Display Symbols (see Figure 2)

Side Panel (see Figure 3)

1. DC Output Terminal: DC analog signal output. Output impedance is around 100 (10mV/dB)
2. AC Output Terminal: AC analog signal output. Output impedance is around 600 (0.707V/ each range scale)
3. CAL potentiometer: Calibration
4. External DC6V: Using the power adaptor DC6V, output plug (3.5) to plug in the terminal. It can use 4pcs of 1.5V batteries or a power adaptor to power up the Meter

Measurement Operation and Functional Buttons

Press and hold for around 1 second to turn the Meter off. HOLD
feature: During sound measurement, press once to freeze the current
reading in the display. Press the button again to resume normal
operation.
A/C| During sound measurement, press the A/C button to select A or C
frequency weighting. With A weighting selected, the frequency
response of the Meter is similar to the response of the human ear.
Weighting is commonly used for environmental or hearing
conservation.

For more information on operating the Sound Level Meter Model UT351 and UT352, please refer to the included operating manual.

B.Display Symbols (see figure 2)

Overview

Sound Level Meter Model UT351 and UT352 (hereafter referred to as “the Meter”) is a stable, safe and reliable sound level meter. The Meter is suitable to use in noise control, quality control, health care and all different kind of environmental noise testing. For example: factory, road, families, musical instruments and all kind of places which need noise testing.
Unpacking Inspection
Open the package case and take out the Meter. Check the following items carefully to see any missing or damaged part:

In the event you find any missing or damaged, please contact your dealer immediately.

Rules For Safe Operation

• Before using the Meter inspect the case and accessories. Do not use the Meter if it is damaged, LCD cannot display, the case (or part of the case) is removed or you consider the Meter does not work properly. Look for cracks or missing plastic.
• When using the Meter, must follow the instruction manual.
• The internal circuit of the Meter shall not be altered at will to avoid damage of the Meter and any accident.
• Replace the battery as soon as the battery indicator appears.
• Turn the Meter power off when it is not in use and take out the battery when not using for a long time.
• Do not use or store the Meter in an environment of high temperature, humidity, explosive, inflammable and strong magnetic field. The performance of the Meter may deteriorate after being dampened.

• Soft cloth and mild detergent should be used to clean the surface of the Meter when servicing. No abrasive and solvent should be used to prevent the surface of the Meter from corrosion, damage and accident.
• Constantly check the battery as it may leak when it has been using for some time, replace the battery as soon as leaking appears. A leaking battery will damage the Meter.

Side Panel (see figure 3)

1. DC Output Terminal: DC analog signal output. Output impedance is around 100Ω (10mV/dB)
2. AC Output Terminal: AC analog signal output. Output impedance is around 600Ω (0.707V/ each range scale)
3. CAL potentiometer: Calibration
4. External DC6V: Using the power adaptor DC6V, output plug ( 3.5) to plug in the terminal. It can use 4pcs of 1.5V batteries or a power adaptor to power up the Meter

International Electrical Symbols

Conforms to Standards of European Union The Meter Structure (see figure 1)

A. Meter Front

1. Housing
2. Windscreen
3. Microphone
4. LCD Display
5. Functional Buttons
6. Signal output and power terminals

Measurement Operation and Functional Buttons
The below table indicated information about the functional  button operations

hold for around 1 second to turn the Meter off. HOLD feature: During sound measurement, press once to freeze the current reading in the display. Press the button again to resume normal operation.
A/C| During sound measurement, press

A/C button to select “A” or “C” frequency weighting. With “A” weighting selected, the frequency response of the Meter is similar to the response of the human ear. “A” weighting is commonly used for environmental or hearing conservation programs ‘C” Weighting is a much flatter response and is suitable for the sound level analysis of machines, engines, etc. Most noise measurements are performed using “A” Weighting and SLOW Response.

For the Model UT352, pressing the A/C button also could recall and clear data:

RECALL:

Press and hold this button, the LCD displays the last data stored and the index number.

Press the button to recall additional stored readings.

Press the button to exit the RECALL mode

CLR:

Press and hold A/C button when turning on the Meter until the LCD displays CLR and RECORD. All the data stored will be cleared.

The Meter is default to auto ranging. Press LEVEL button to switch to manual ranging. Press button to toggle from

low to high range or from high to low

range. Press and hold LEVEL button to exit the manual ranging mode.

FAST/ SLOW| Press to select a FAST (125ms) or a LOW (1 second) response time. Select FAST to capture noise peaks and noises that occur very quickly. Select the LOW response to monitor a sound source that has a consistent noise level or to average quickly changing levels. Select LOW response for most applications.

Press and hold the FAST/SLOW button to enable the display backlight. Press and hold FAST/SLOW button again to disable the display backlight.

For UT352, press the FAST/SLOW button to store data:

Press the HOLD button to freeze data, the LCD displays HOLD and M symbol and the data being stored.

Press FAST/SLOW to store the data, the symbol RECORD and the number of index blink for 0.5 seconds.

The Meter will automatically exit HOLD mode.

The Meter can store up to 63 data.

MAX/ MIN| Press MAX/MIN to display the maximum or minimum reading. The display

will update only when the measured value exceeds the value present in the display. Press the MAX/MIN button and the MAX icon will display on the reading. The reading displayed is the highest reading encountered

since the MAX mode was entered.

The read ing displayed is the lowest reading encountered since the MIN mode was entered.

Press the MAX/MIN button again to exit the MAX/MIN display mode

Press and hold MAX/MIN button to disable or enable auto power off feature. The Meter will automatically off after approximately 15 minutes of inactivity.

The icon display indicates that the auto power off feature is active.

Calibration (see Figure 4)

1. Turn the Meter on.
2. Put the Meter in the “A” weighting mode, FAST response mode, range set to 60~110dB, lock to MAX.
3. Place the microphone onto the calibrator’s 1/2 inches sound source hole.
4. Turn the calibrator on, using a 94dB@1kHz standard sound source.
5. Adjust the Meter’s CAL potentiometer located on the side panel until the LCD displays 94.0dB

Specifications

A. General Specifications

• Display: 3 1/2 digits, 1999 maximum
• Overloading: Under range displays UNDER Over range displays OVER
• Battery Deficiency: Change batteries as soon as is displayed.
• Sampling Rate:
• Fast Speed: 125 microseconds
• Slow Speed: 1 second
• Microphone: 1/2” electret condenser
• Drop Test: 1-meter pass
• Battery: 4 x 1.5V batteries (AA)
• Battery Life: Typical 20 hours continuous
• Dimension: 273 x 69 x 39mm
• Weight: around 386 g (including batteries)

B. Environmental Requirements

• For indoor use only.

• Altitude: 2000m

• Temperature and humidity:

  • Operating:
    0 ~30 (≤80%R.H)
    30 ~40 (≤75%R.H)
    40 ~50 (≤45%R.H)

  • Storage:
    -20 ~ +60 (≤80%R.H)

• Safety/ Compliances:
  EN61326: 1997+A1:1998+A2:2001+A3:2003,
  EN61672-1: 2002 Class 2 and IEC60641:1979 Type 2,
  ANSI S1.4: 1983 Type 2

• Certification:

Accuracy Specifications

• Accuracy: ±(a% reading + b digits).guarantee for 1 year.
• Operating temperature: 23 ±5 .
• Relative humidity: ≤80%.
• Temperature coefficient: 0.1 x (specified accuracy) / 1C

A. Decibel dB

A-Weighting and C-Weighting

| 30~80dB|

0.1dB

|

±1.5dB

|

Frequency Response 31.5~8kHz

50~100dB
60~110dB
80~130dB

Sampling Rate

| FAST| | | Sampling Time: 125 microsecond
SLOW| | | Sampling Time: 1 second

Analogue Bar Graph

|

30~130dB

|

1dB

| | 1 dB per scale,

Sampling time: 200 times per second

Overloading| | | | Over range display: OVER Under range display: UNDER
DC analogue signal

output

| Output impedance around 100Ω, 10mV/dB| | | Has input terminal
AC analogue signal

output

| Output impedance around 600Ω, 0.707V/ each scale| | | Has input terminal
Power (HOLD)| | | | Turn on and off the Meter and data

holding

LEVEL (AUTO)| | | | Selecting auto and manual ranging

A/C (RECALL/CLR)

|

A-Weighting and

C-Weighting selection

| | | RECALL/CLR features are for model UT352 only. Press to recall and clear data
FAST/SLOW (STORE/BL)| Selection of fast or slow sampling rate and turn on and off of display backlight| | | STORE feature is for model UT352 only. Press to store data
MAX/MIN (Auto ranging)| Selection of maximum and minimum value.

Selection of auto power on and off

| | |

Maintenance

This section provides basic maintenance information including battery replacement instruction. Warning Do not attempt to repair or service your Meter unless you are qualified to do so and have the relevant calibration, performance test, and service information. To avoid electrical shock or damage to the Meter, do not get water inside the case. In order not to affect the Meter accuracy or damge to the Meter, do not open the Meter housing
A. General Service

• Periodically wipe the case with a damp cloth and mild de tergent. Do not use chemical solvent.
• To clean the terminals with cotton-tipped swab with de tergent, as dirt or moisture in the terminals can affect readings.
• Press the Meter power off when it is not in use and take out the battery when not using for a long time.
• Do not store the Meter in place of humidity, high tem perature, explosive, inflammable and strong magnetic field

B. Replacing the Battery (see figure 5)

Warning
To avoid false readings replace the battery as soon as the battery indicator appears.
To replace the battery:

1. Press the Meter power off
2. Remove the screw from the battery compartment, and then take out the battery door from the battery compartment.
3. Remove the battery from the battery compartment.
4. Replace the battery with 4pcs new 1.5V AA batteries
5. Rejoin the battery door and the battery compartment, and install the screw

Copyright 2008 Uni-Trend Group Limited. All rights reserved.

• Manufacturer: Uni-Trend Technology (Dongguan) Limited
• Dong Fang Da Dao
• Bei Shan Dong Fang Industrial Development District
• Hu Men Town, Dongguan City
• Guang Dong Province
• China
• Postal Code: 523 925
• Headquarters:
• Uni-Trend Group Limited
• Rm901, 9/F, Nanyang Plaza
• 57 Hung To Road
• Kwun Tong
• Kowloon, Hong Kong
• Tel: (852) 2950 9168
• Fax: (852) 2950 9303
• Email: info@uni-trend.com.
• http://www.uni-trend.com.

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