Brüel & Kjær 3638 Manuel De L'utilisateur page 36

32 Exhaust Noise Inspector Type 3638 – User Manual
11) When the green LED starts flashing, release the throttle rapidly and allow the engine speed
to return to idle. The sound level meter measures from the time the RPM trigger occurs
until the engine has returned to idling position. The maximum sound level detected during
that period is used as the result.
12) Repeat steps 1 – 5 at least three times – the number of times depends on the applicable
legislation (see "Number of Measurements Setting" on page 14 for setting of this system
parameter). The results from the consecutive measurements must be within 2 dB of each
other. If not, the system will continue in measurement mode until this condition is satisfied.
When the required number of consecutive measurement results is within 2 dB, the system
automatically prints out the results. The highest measured value is considered the test re-
sult.
13) Sound level measurement is complete when the report is printed.
For more information on Tachometer Type 2979, see the manual accompanying the instrument.
Sound Level Meter
Fig.4.5 Sound level meters Types 2238 and 2239 A
You will need to familiarise yourself with the following keys on the sound level meters:
Start/Stop/OK
Calibration
Measure/Cancel
Up arrow
Mediator Type 2238
Press this key during calibration to confirm a menu selection
Press this key to calibrate the sound level meter. See the section
"Calibration" on page 24 for calibration instructions
While calibrating, press this key to cancel calibration
Press this key to make changes in the current window
Type 2239 A