26
SVANTEK 977W User Manual
Optional measurement functions that broaden the application of the instrument can be easily installed. These
options can be initially supplied by the manufacturer or purchased later and added by the user.
Note: It is not possible to change the measurement function during a measurement run. In this case
the instrument displays for about 3 seconds the message:
“Measurement in Progress”. To change
the mode of the instrument the current measurement in progress must be finished!
4.3.
Instrument’s calibration – Calibration
The instrument is factory calibrated with the supplied microphone for the standard environmental conditions.
Because the microphone sensitivity is a function of the temperature, ambient pressure and humidity, when the
absolute sound pressure level value is important, the absolute calibration of the measurement channel should
be performed. To select the calibration function, the user should enter the
Calibration
sub-list.
The
Calibration
sub-list consists of positions
which are used to perform the in-situ checks
and
calibration
(
System Check
,
Calibr. by Sensitivity
,
Calibr. by Measurement
),
check
the
calibration records (
Calibration History
) as
well as perform additional calibration after the
measurement session and add the results to
the file (
Post Calibration
).
<ENT>
To have access to the instrument’s
calibration (positions
Calibr. by Sensitivity
or
Calibr. by Measurement
)
in
the
Sound Meter
mode the user should have a
special right and know the
Code
to unlock
these positions.
<ENT>
Note: The new calibration factor for Sound Meter
mode can be saved if it differs less than ±1.1 dB
from the factory one, or the last one defined by the authorised user and recorded in the Calibration
position (path: <Menu> / Welmec / Service / Calibration).
In the
Vibration Meter
mode, all calibration
positions don’t require special
unlocking code. In addition to the
Sound Meter
mode there is one additional
position enabled the user to clear calibration records (
Clear Calibr. History
).
Note: The calibration factor is always added to the results and measurement range limits in the
Level Meter, 1/1 Octave, 1/3 Octave modes.
Note: It is advised to perform the system check of the instrument each time before the measurements
begin. If system check shows negative result, then it is necessary to perform calibration.
Note: The calibration level and the calibration result are expressed in different units depending on
the settings of the instrument. The metric or non-metric Vibration units are set in the Vibration Units
window (path: <Menu> / Auxiliary Setup / Vibration Units). Additionally, the linear or logarithmic units
are set in the Display Scale window (path: <Menu> / Display / Display Scale).
Note: It is not possible to check and calibrate the instrument during the execution of live
measurements. It is possible to open different lists and sub-lists but the positions in these lists are
displayed greyed out inversely and so -
not accessible. The flashing “
►
” icon on the top line indicates
