MasterCool 52238 - Digital Sound Level Meter Manual

INTRODUCTION

This sound level meter provides automatic or manual ranging, 4 measurement ranges from 40 to 130 dB, and features 0.1dB resolution. The meter allows you to select between fast and slow response times as well as A and C weighting. A maximum hold function is provided. Jacks on the meter provide AC analog output.

BUTTON DESCRIPTION

: Power on or power off the meter

RNG: Auto Range/Manual range

REC: Record Maximum and Minimum sound level measurement

A/C: A weighting and C weighting

F/S: Response

MAX HOLD: Freeze Maximum sound level reading

MEASURING SOUND LEVELS

Sound levels are displayed both digitally and in a bar graph. The digital display is updated every 160ms, while the bar graph is updated every 40ms.

Press the key to turn the meter on. The unit will first display the full LCD and "188.8" (see Fig. A) then count down from 99.9 to zero (see Fig B.) The meter will now begin measuring the current sound levels. SPL (Sound Pressure Levels) appears on the left side; "A'', "dB" on the right side of the LCD. Point the microphone toward the source of the sound to be measured.

SELECTING THE RESPONSE TIME

You can select a fast or slow response time to suit different applications and standards. For example, most OSHA-related testing is done using slow response time and A weighting. When you turn the meter on, it will be in fast response mode (see Fig. C.) Press the F/S key to toggle between fast and slow response. A small icon, FAST or SLOW, will be displayed on the top of the LCD to indicate the current mode (see Fig. D.)

SELECTING A AND C WEIGHTING

When you turn the meter on, it will be in A weighting mode. A weighting enables the meter to respond in the same manner as the human ear, which increases and decreases amplitude over the frequency spectrum. Applications for A weighting include OSHA regulatory testing, environmental measurement, workplace design, and low enforce-ment.
C weighting is suitable for flat response measurements with no increase or decrease of amplitude over the frequency spectrum. Applications for C weighting include the sound level analysis of engines and machinery. Press the A/C key to select between A and C weighting. A small A or C icon will be displayed on the right side of the LCD to indicate the current mode (see Fig E.)

FREEZING THE MAXIMUM SOUND LEVEL READING

1. Press the key to turn the meter on.
2. When measuring sound levels, press the MAX HOLD key to freeze the maximum reading. MAX HOLD will be displayed (see Fig F.) The LCD will remain unchanged until a higher reading is detected. Note that the bar graph will continue to record the current reading.
3. Press the MAX HOLD key again to exit maximum hold mode.

RECORDING MAX AND MIN MEASUREMENTS

1. Press the key to turn the meter on.
2. Press the REC key. The REC icon will be displayed in the upper left corner of the LCD (see Fig. G.) The meter will begin tracking the maximum and minimum sound level measurements.
3. Press the REC key again. The MIN icon will appear in the upper middle of the LCD (see Fig. H) and the minimum sound level measurement will be displayed. The unit is not recording at this time, but the bar graph will continue to show the current reading.
4. Press the REC key again. MAX will appear on the LCD by "REC" and the maximum sound level measurement will be displayed. The unit is not recording at this time, but the bar graph will continue nto show the current reading.
5. Press the REC key again to resume recording and repeat the process.
6. Press and hold the REC key until the REC indicator disappears to exit recording mode.

SELECTING AUTOMATIC AND MANUAL RANGING

The meter features 4 measurement ranges in 10dB steps: 40~70dB, 60~90dB, 80dB~110dB, 100dB~130dB. The meter will be in automatic range mode when turned on and a small AUTO will be displayed on the left side of the LCD. In this mode, the meter will adjust the measurement range automatically for accuracy. The two digit number to the left of the bar graph will show the low end of the current range.
The meter will take readings quicker in manual mode, because the unit does not need to first establish the range before displaying the measurement. This is helpful when you know the measurement range in advance.

To Adjust The Range Manually:

1. When measuring sound levels, press the RNG key as needed to adjust the measurement range. MANU will appear on the LCD (see Fig I.) Note that the two digit numbers to the left of the bar graph will change to reflect the low of the newly selected range.
2. Press the RNG key to return to automatic ranging. If the meter is operating in manual range and "LO" is displayed (see Fig J), the sound is too low. If "HI" is displayed, the sound is too loud. In either case, you must adjust the measurement range or your readings will be inaccurate.

AUTOMATIC SHUTOFF

The meter will turn off automatically after 20 minutes to preserve the battery. To override this feature:

1. Make sure the unit is turned off.
2. Press the and MAX HOLD keys simultaneously.
3. When the full display appears, release the button, when the "Π" icon appears on the LCD, release the MAX HOLD key, "Π" will be replaced with the full display (see Fig. K.)
4. The meter will remain on until the key is pressed again. The automatic shutoff feature will resume the next time the meter is turned on.

REPLACING THE BATTERY

When the "" icon appears, the 9V battery has fallen to a critically low voltage level and should be replaced. Use a screwdriver to unscrew the back battery compartment cover (see Fig. L). Insert a fresh 9V battery and screw the cover back on.

CE CERTIFICATION

The meter conforms to the following standards:
EN 50081-1/1992: EN 55022
EN 50082-1/1997: (EN 61000-4-2/-3/-8,ENV 50204)
The meter complies with the essential protection requirements of Council Directive 89/336/EEC on the approximation of the laws of the Member States relating to electromagnetic compatibility.

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