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Optimus VNK - Quick Start Guide
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Performing measurements
Once your Optimus VNK is set up, you're ready to begin taking vehicle noise measurements.
The following section sets out how to use the Optimus VNK to make measurements to ISO
5130-2007 and §29 StVZO standards.
With the car's engine running at its normal temperature and the Optimus+ sound level
meter turned on, gently press the accelerator to achieve the appropriate number of
revolutions per minute for your vehicle (as per section 6.4 of ISO 5130-2007). You can use
your car's rev counter as a guide.
Gradually press the throttle to achieve the correct engine speed. Once you're at the correct
RPM, press and hold the vehicle noise trigger button to begin the first reading.
Hold the engine speed for at least one second whilst
continuing to hold the trigger button. Then, rapidly
release the throttle and allow the engine to return to
idling speed, keeping the trigger button pressed. Once
idling, you should release the trigger button.
The first measurement will be recorded in position
one on the Vehicle Noise screen on your Optimus+.
The measurement will be the LAFMax for the duration
of when the engine was at the target speed and
throughout the deceleration period.
For your overall measurement to be compliant with
the international standard, three measurements
must be taken. Your Optimus+ sound level meter will
automatically calculate the LArep from these three
measurements, which will constitute the result for
that measurement period.
Once you have captured the first reading, repeat the
process as described above to capture the second
value. The second measurement will appear in position
one on the screen of your Optimus+.
Taking Vehicle Noise Measurements With The VNK
Repeat the process a final time to capture the last
measurement. The third measurement will appear in
position one on the screen of your Optimus+.
Once three measurements have been taken, the LArep
(average of the three measurements) will automatically
be displayed. This value should be given as the result
of the noise test you've just conducted.
If you wish to test another vehicle with the same
instrument or retest the same vehicle, simply press
the trigger button again when you are ready to take a
measurement. This will overwrite the value in position
one, as shown below.
Alternatively, you can press 'Menu' or the middle button to open the menu, and then the
'back' button to exit. This will reset the vehicle noise display.
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