B&K 2250 Light Bedienungsanleitung PDF herunterladen (Seite 66)

Hand-held Analyzer Types 2250 and 2270 – User Manual

Note: The Auto detect setting enables the automatic detection of the calibration level. For

free-field microphone types (like Types 4189 and 4190) the calibration level from Sound

Calibrator Type 4231 is either 93.85 dB or 113.85 dB. For diffuse- or pressure-field types,

the calibration level is either 94 dB or 114 dB. The calibration process automatically

determines the correct level

• Calibrator Serial Number: Type in the serial number for your calibrator. The calibrator

will be documented in the calibration history

5.4 Vibration Calibration

To calibrate an accelerometer use Calibration Exciter Type 4294. It provides a stable

acceleration of 10 m/s

at 159 Hz. The procedure for mounting the accelerometer to the exciter

is described in the Type 4294 user manual. Otherwise the calibration procedure is very similar

to the Standard Calibration procedure for sound calibration described above. However, if the

calibration deviates more than ± 5.5 dB from the nominal sensitivity, the calibration is stopped

without changing the calibration of the analyzer. In this case, check whether the correct

accelerometer has been selected from the transducer database and whether it has the correct

nominal sensitivity.

Note: If you use Low Level Accelerometer Type 8344, you need Calibration Exciter

Type 4294-002.

5.5 Electrical Calibration

To calibrate the Direct input use a stable sinusoidal voltage at a frequency between 150 Hz and

10 kHz. The procedure is very similar to the Standard Calibration procedure for sound

calibration described above; however, without the transducer mounting procedure.

5.6 Manual Calibration

If no calibrator is available (or a known amplification is introduced, that is, by analyzing a tape

recorded signal) then you can type the sensitivity directly into the Sensitivity field. The

analyzer will be regarded as un-calibrated and the text ‘Uncal.’ will appear in the Status Field.

5.7 Calibration History

To view calibration history, tap Calibration History > on the Calibration Details screen (Fig.5.2).

The analyzer saves the last 20 calibrations, plus initial calibration, which can be viewed on the

Calibration History screen (Fig.5.3). Tap to return to the calibration details screen; tap

again to return to the Measurement screen.

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B&K 2250 Light Bedienungsanleitung Seite 66