Instruction Manual
Sound Level Meter Types 2245 –
Instruction Manual
Page 30 of 110
Press Stop to a stopped measurement to reset the latched overload and to reset
all time-weighted sound levels to zero (–∞ dB). From this, they increase to their current
values. The timed measurements derived from time-weighted sound levels (e.g.,
Minimum Time-weighted Sound Level, Maximum Time-weighted Sound Level,
Equivalent Continuous I- weighted Sound Level, Taktmaximal-Mittelungspegel, and
Statistics) are fist valid after this has settled. The settling time is less than 1 s for Fast
weighting and less than 2 s for Slow weighting. Therefore, it is recommended to wait a
couple of seconds after a reset before starting the measurement. Measurement of
Equivalent Continuous Sound Level, Sound Exposure Level, and Peak Sound Level are
not influenced by this start-up settling after a reset.
Note: Changing microphone, windscreen or weightings will also make a reset.
Latched Overload
For the timed measurements, a latched overload indication is displayed and included
in the set of results if the overload condition exists at any time during the measurement
time interval. The latched overload is indicated by a magenta triangle on the screen.
The latched overload is common to all the results of the timed measurements.
Minimum Time-weighted Sound Level
The minimum time-weighted sound level,
L
xymin
(T)
, is defined as the smallest time-
weighted sound level,
L
xy
(t)
, within a time interval starting at
t
=
T
and ending at
t
=
T
+ Δ
t
where:
x
is A for A-weighted, B for B-weighted, C for C-weighted or Z for Z-weighted
y
is F for Fast-weighted, S for Slow-weighted or I for Impulse-weighted
T
is the start time of the measurement, indicated as
Start Time
Δ
t
is the measuring period, indicated as
Elapsed Time
The minimum time-weighted sound level is expressed in decibels (dB).
The symbols used by the sound level meter for maximum time-weighted sound levels
are (for A, B, C and Z frequency weighting and F, S and I time weighting):
L
AFmin
,
L
ASmin
,
L
AImin
,
L
BFmin
,
L
BSmin
,
L
BImin
,
L
CFmin
,
L
CSmin
,
L
CImin
,
L
ZFmin
,
L
ZSmin
,
L
ZImin
Maximum Time-weighted Sound Level
The maximum time-weighted sound level,
L
xymax
(T)
, is defined as the greatest time-
weighted sound level,
L
xy
(t)
, within a time interval starting at
t
=
T
and ending at
t
=
T
+ Δ
t
where:
x
is A for A-weighted, B for B-weighted, C for C-weighted or Z for Z-weighted
y
is F for Fast-weighted, S for Slow-weighted or I for Impulse-weighted
T
is the start time of the measurement, indicated as
Start Time
Δ
t
is the measuring period, indicated as
Elapsed Time
The maximum time-weighted sound level is expressed in decibels (dB).
The symbols used by the sound level meter for maximum time-weighted sound levels
are (for A, B, C and Z frequency weighting and F, S and I time weighting):
L
AFmax
,
L
ASmax
,
LA
Imax
,
L
BFmax
,
L
BSmax
,
L
BImax
,
L
CFmax
,
L
CSmax
,
L
CImax
,
L
ZFmax
,
L
ZSmax
,
L
ZImax