407738 Datasheet, PDF (5/8 Pages) Extech Instruments Corporation. – Digital Sound Level Meter

Power Supply
The meter can be powered by one 9V battery or by the specified optional AC power
adaptor. Before inserting or replacing the battery and before connecting the AC adaptor,
be sure to turn off the meter.
Battery Installation
Remove the battery compartment cover (lower back of the meter) and install or replace the
9V battery.
Fully charged
Battery Capacity Indicator
The battery status indicator on the meter’s display (see diagram)
informs the user of the battery’s condition. The number of segments in
the display icon decreases as the battery weakens. When all segments
switch off and the icon flashes, the meter is about to lose power.
Partially charged
AC Voltage Adaptor
Insert the AC adaptor into the DC 9V jack on the side of the meter.
Connect the other end of the adaptor to an AC source. With a battery
installed and the AC adaptor in use, the AC adaptor has priority.
Replace battery
Measurements
1. Turn the meter ON by pressing the button. The default settings are: ‘A’ frequency
response; ‘FAST’ response time; and 70 to 130dB range
2. Select the frequency weighting ‘A’ or ‘C” as desired using the ‘A’ or the ‘C’ buttons.
Typical sound level measurements use ‘A’ weighting.
3. Press the ‘FAST’ or ‘SLOW’ button to select the desired response time. Normally the
‘SLOW’ setting is used.
4. Use the up and down buttons to select the appropriate range. The range is shown at the
top left corner (low end of range) and top right corner (high end of range) of the LCD.
Use a range that puts the sound level reading in the center of the bargraph. If the OV
(over-range) or UN (under-range) icons appear with dashes on the main display area,
select a new range. Refer to the Specifications page for the list of available ranges.
5. The numeric and bargraph displays indicate the sound level measurement. The
numerical reading updates every second while the bargraph updates every 125ms.
MAX / MIN Operation
The Model 407738 stores the highest (MAX) and lowest (MIN) readings in its memory. The
stored MAX and MIN values are continually updated as new MAX and MIN values are
encountered. The user can recall these stored readings using the MAX button as
described in the steps below. Before starting, select an appropriate range as described
previously, otherwise the stored MIN/MAX readings may indicate all dashes (out of range).
1. Press the MAX button and the MAX icon will appear on the LCD. The reading shown is
the highest reading encountered since the meter was last reset. Note that the elapsed
timer display shows the time at which the MAX reading was recorded.
2. Press the MAX button again. The MIN icon will appear on the LCD and the reading
shown represents the lowest reading encountered since the meter’s memory was last
reset. The elapsed timer display shows the time at which the MIN reading was recorded.
3. Press the MAX button again to exit the MAX / MIN display mode (the MAX and MIN
display icons switch off when this mode is exited).
4. To clear the MAX / MIN memory, simply press the up or down arrow to change range.
Note that the elapsed timer starts when the meter is switched ON and continues running
until the meter is shut off or until 100 hours is reached.
5
Model 407738 Version 2.2 September 2005