General Tools and Instruments DSM403SD - Manual (Page 6)

5. Enable or disable auto power off (APO). Once the format of decimal point divisions has
been set and stored, the display will show the word “yES’ over the term “PoFF”. Press
the ▼ or ▲ button until the desired APO management scheme (“yES” for enable; “no” for
disable) is displayed. Press the REC/ENTER button to store the selection. If enabled, the
APO function shuts off the DSM403SD if no front-panel buttons are pressed for ten
minutes.
6. Enable or disable the beeper. Once the APO function has been enabled or disabled, the
display will show the word “yES” over the word “bEEP”. Press the ▼ button until the
desired setting (“yES” or “no”) is displayed, and then press the REC/ENTER button to
store the selection as the default.
7. Set the data logging sampling time. Once the beeper has been enabled or disabled,
the display will show a value above the letters “SP-t”. Press the ▼ or ▲ button to
decrease or increase the value until the desired sampling time appears above “SP-t”.
The options are 0, 1, 2, 5, 10, 30, 60, 120, 300, 600, 1800 and 3600 seconds (0 seconds
to 1 hour).
8. Format the SD card. Once the sampling time has been set and stored, the term “Sd-F”
will appear in the lower half of the display. Press the REC/ENTER button.
Pressing the REC/ENTER button causes the word “no” or “yES” to appear over the term
“Sd-F”. Press the ▼ button to make a selection. Choose “yES” whenever a new SD card is
being used, or when a used card is being repurposed (from use with another SD card
instrument or a camera, for example) and all data on it is to be erased. Choose “no” to
preserve any data on a card previously used with this instrument.
If you choose “yES”, after you press the REC/ENTER button the instrument will prompt you
to confirm that decision by displaying the term “Ent” below “yES” and sounding three
beeps (if the beeper is enabled). To confirm that you want to begin the erasure/formatting
procedure, press the REC/ENTER button. “Ent” will then flash several times and the
instrument will sound another three beeps to confirm that the SD card has been erased and
formatted.
Once the SD card has been formatted (or not), the display will return to the first of the six
steps in the setup sequence—setting the current date and time. To re-enter the setup
sequence in order to change one or more settings, press the REC/ENTER button. If you are
satisfied with the existing settings, press the POWER/ESC button to exit setup mode and
enter normal operating mode.
CALIBRATING THE METER
The DSM403SD must be calibrated before it can make accurate sound level measurements.
1. To prepare for calibration, obtain a sound calibrator and mate its output connector with
the head of the DSM403SD’s microphone (callout 1-9 of Fig. 1). Power on the sound
calibrator and manually set its range to 50 to 100 dB.
2. On the DSM403SD, manually set its range to 50 to 100 dB as well by pressing the
▲ button (which has the word “Range” stenciled above it) once. The display will then
show the first of three range options: “30 – 80”. Press the ▲ button again and the
display will show the second option: “50 – 100”.
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