CESVA SC-30, Руководство пользователя, Страница: 17 / 76

SC-30
User’s Manual
15
1) Insert the SC-30 into the CB006 calibrator,
introducing the microphone into the
calibration cavity. Make sure the
microphone reaches the bottom of the
cavity and is parallel to the calibrator axis
(see figure). This may require a little effort
since the sound level meter must fit exactly
into the calibrator. Insert the SC-30 gently;
otherwise
you might damage the
microphone.
2) Turn the calibrator on and check the state
of the batteries. The luminous indicator
must be lit throughout the calibration
process.
3) Apply the free field to pressure corrections
of the microphone at 1 kHz and those
corresponding
to the influence of
atmospheric pressure, temperature and
humidity in the calibrator. The free field to
pressure correction for C-130 and C-250
microphones at 1 kHz is 0.1 dB.
That is the SC-30 should be set to read
93,9dB.
4) Switch the SC-30 to numeric sound level
meter mode ( 2.3.3) using the keys:
5) Select the sound pressure level with fast time weighting (FAST) L
AF
, L
CF
or L
ZF
as the
function to measure. NOTE: The frequency weighting makes no difference since
calibration takes place at 1 kHz.
6) Begin measuring with the SC-30 in numeric sound level meter mode:
7) Check that the value which appears at the top of the screen (large digits) coincides
with the value of 94.0 dB corrected with the corresponding corrections normally (93.9
dB).
If the value of the reading differs more than
±
0.3 dB from the calculated value, the sound
level meter sensitivity needs adjusting. If not, the meter is reading correctly and there is no
need to readjust its sensitivity.
NOTE: The sensitivity of the SLM must only be adjusted by authorised, technically qualified
personnel. Readjustment of the sensitivity entails the loss of traceability in the calibration of
the instrument.
If the results of checking the SC-30 show a deviation of more than 0.3 dB, adjust the
sensitivity as follows:
1) Press the key to terminate the measurement process.
2) Do not switch the CB006 calibrator off; keep it in the calibration position.
3) Next press to access the SC-30 menu.