Casella CEL CEL-63X - Manual (Page 14)

CEL-63x Environmental & Occupational Noise Meter
14 Casella CEL
Each measurement run stores both the before-run and the after-run calibration
results, including any changes in the calibration. This confirms the absolute
accuracy of the measurement.
NOTE
It might be necessary to change the calibration reference level so that it includes the
pressure-to-free field correction applicable to the fitted microphone. For Casella
microphones, and assuming a 114.0 dB nominal calibrator pressure, the reference
level should be as follows:
• CEL-251 or CEL-252 = 114.0 dB (if using windshield)
• CEL-251 or CEL-252 = 113.9 dB (without windshield)
1. Remove the windshield from the CEL-63x instrument‟s microphone.
2. Press and release the ON/OFF key to switch the instrument ON.
3. Wait approximately 10 seconds until the instrument‟s initialization
screen changes to the Status screen.
4. Press the Menu Soft key to see the instrument‟s Settings menu.
5. Follow the instruction steps shown in Figure 3 to set the instrument‟s
calibration reference level so that it is the same as the sound pressure
level that the calibrator generates.
Figure 3. Setting the instruments calibration reference level
6. Save and exit to the Measurement screen.
7. Gently fit the calibrator to the instrument‟s microphone and press it into
position as shown in Figure 4.