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INTRODUCTION
Thank you for purchasing General Tools & Instruments’ DSM403SD Class 1 Sound Level
Meter with Datalogging SD Card. Please read this user’s manual carefully and thoroughly
before using the instrument.
The DSM403SD is a general-purpose handheld instrument that measures the noise level of
an environment or the sound level produced by a piece of machinery. Using an integrated
0.5-inch condenser microphone, the meter can measure sound levels from 30 to 130 dB
with a resolution of 0.1 dB and show the results on a front-panel liquid-crystal display.
The DSM403SD has several user-settable measurement parameters, such as frequency
weighting (using the “A” and “C” standards) and time weighting (fast or slow). The “A”
frequency weighting characteristics meet the Class 1 standard of IEC 61672. Several other
features and capabilities enhance the meter’s versatility. Among them are autoranging and
the ability to hold readings and display maximum and minimum readings. The DSM403SD
can be calibrated by an optional laboratory instrument.
Because it is microprocessor-based, the DSM403SD can make full use of the portability,
reliability and large storage capacities that SD memory cards offer. Measurements can be
made automatically at any sampling rate between one second and one hour. After time-
stamping and storing the measurements on an SD card plugged into the instrument (a
process called datalogging), the user can remove the card and plug it into to a laptop or
desktop computer either directly or via a USB card reader. The data logs are stored on the
card as files with the .xls extension, which can be opened by Microsoft’s Excel application.
The DSM403SD has a backlit 2-1/2 in. diagonal display and is powered by six “AA” Alkaline
batteries or an optional 9-VDC AC adapter.
KEY FEATURES
• Measures sound levels of machinery or an environment
• Big (2.5 in. diagonal) front-panel green backlit LCD is easy to read
• Makes measurements in autoranging mode or within a manually settable range
• Displays maximum and minimum readings and holds any reading
• Performs automatic datalogging at sampling time settable from 1 second to 9 hours
• Also supports manual logging and changing of card storage location
• Outputs Excel-compatible data logs
• Accepts SD memory cards of up to 16 GB capacity
• Auto power off function
• Powered by six “AA” batteries or optional 9V AC/DC adapter