General Tools and Instruments DSM8921 - Manual (Page 12)

2 Press and hold the DOWN or UPPER
key to switch back to automatic
ranging.(See Fig.11)
If the meter is operating in manual
range and UNDR is displayed (See
Fig.13) , the sound is too low or the
range. If UPER is displayed (See
Fig.14) ,the sound is too loud.
In either case, you must adjust the
measurement range or your readings
will be incaccurate.
1 When measuring sound levels,press
the DOWN and UPPER keys as
needed to adjust the measurement
range. MANU will appear on the
display (See Fig.12) .Note that the
two digit number to the left of the
bar graph will change to reflect the
low of the newly selected range.
TO ADJUST THE RANGE MANUALLY:
Fig.13
+10
SPL SPL
UNDR
Fig.14
+10
SPL SPL
UPER
AUTOMATIC SHUTOFF
The meter will turn off automatically
after 20 minutes to preserve the
battery.