185
Norsonic Nor140
Instruction Manual
185
Socket for external
DC
:
1.3 mm plug, negative volt-
age on centre terminal.
The instrument will automatically switch off if the bat-
tery or external voltage is too low for operation within
the stated specifi cations. The maximum battery volt-
age for conformance testing is 4 × 1.6 V = 6.4 V.
The instrument has a calendar clock powered from
the batteries or external DC-supply. The clock is sup-
plied from a charged capacitor during change of bat-
teries. Contact your Norsonic service department for
change of this component. After replacement the in-
strument need factory calibration and to re-install the
options.
Display
The display is a monochrome, transrefl ective LCD
graphical display with 160×240 pixels (W×H) with au-
tomatic temperature compensation for contrast and
viewing angle. Pressing the light key illuminates the
display. The light switches off automatically 2 minutes
after the last operation of any key.
The bar graph display covers 80 dB, which may be
scrolled in 10 dB steps to cover the total range.
Keyboard
The keyboard is of silicon-rubber type.
Adjustment of indicated levels
Random response.
The instrument is equipped with
a microphone with fl at free-fi eld response and satisfi es
the class 1 requirements in IEC 61672-1 to free-fi eld
response. By selecting the random response
correction network included, the instrument will satisfy
the class 1 requirements in IEC 61672-1 to random re-
sponse as well as ANSI S1.4-1997 type 1. The nominal
correction to obtain fl at random response is shown in
the fi gure above.
Activating random response correction:
•
Press
SETUP
>
1
(Instr.) >
4
(Input) >
2
(Corrections)
to gain access to the Corrections menu. Navigate
in the menu as usual and activate the correction
parameter Random by means of the
INC
and
DEC
keys. Do the same to deactivate. Random response
correction activated is indicated by an “
R”
in the
lower line of the display.
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