Norsonic nor140, Instructional Manual, Page: 114 / 220

96
Chapter 19
Reference Spectrum
Editing a selected
Reference Spectrum
Use cursor keys to move the field indicator in row with
the frequency band to be edited. Use the
INC
and
DEC
keys to adjust the value (in 0.1 dB steps) or use
the numerical keys to enter the desired new value. Al-
ternatively, use the
DEL
key to clear the value.
If the values from one or more bands are deleted,
the Reference Spectrum indicators for these bands are
NOT
presente d in the graphical display.
A-pre-weighted Reference Spectrum
The Reference Spectra saved in the instrument are
always stored as unweighted values. However, if the
A-pre-weighting display feature is used during the
comparison, both the displayed Reference Spectrum
and the measured frequency spectrum will be pre-
weighted.
“Go / NoGo” Quality Control feature
The Reference Spectrum feature may be used to give
a “Go” or a “NoGo” output signal in quality control ap-
plications. This additional feature is found in Ref. curve
(
SETUP 4 > 1
) menu as the “QC” setting.
There are three selections for the QC feature:
Off: No “Go / NoGo” comparisons are made
On: The “Go / NoGo” comparisons functions con-
tinuously before, during and after the measure-
ment. When selected On, a sub menu appears,
where you may select a
Delay
. This delay will
hold the Go/NoGo comparison signal on the
digital I/O active the number of second that is
entered. Any value between 0 and 99 seconds
is accepted. This feature is especially useful
when an alarm lamp or other type of warning
device is connected to the instrument. The
alarm will then stay on as long as the signal is
outside the reference spectra plus the number
of seconds entered in the
Delay
field.
End: The “Go / NoGo” comparisons functions only
after the measurement has been ended or
stopped
The status of the “Go / NoGo” comparison is displayed
as a “Go” or a “NoGo” symbol within the L(f) display.
As the Reference Spectra only contain dB-values, the
currently selected spectra function (Leq, Lmax, Lmin,
etc selected by the
FUNC
key) will be the basis for the
comparison of the actual measurement spectrum with
the currently stored and selected Reference Spectra. All
frequency band values of the actual measured spectrum
must fulfil the actual requirements of the saved Refer-
ence Spectra in order to get a “Go” status.
Comparison between reference and measured
spectrum. A-preview is selected