Larson Davis CAL200, Руководство пользователя

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2-4 Microphone Calibration CAL200 Manual
Step 5
Make a reading. If the reading is not within
tolerance, refer to the instrument’s manual for instructions
on how to adjust the instrument.
Step 6 Check the ambient noise level to insure that the
calibration was not influenced by noise from external
sources. The CAL200 needs to be on the microphone but
with the CAL200 signal off. External noise levels lower than
89 dB SPL for the 114 dB level calibration, and 69 dB SPL
for the 94 dB calibration level will influence the calibration
by less than 0.015 dB.
Each time the ON button is pressed,
the CAL200 calibrator will run
approximately 60 seconds on a fresh
battery. In order for the calibrator to
turn off, do not press the ON button
again. Wait until the calibrator times
out. It is not an ON/OFF button. As the battery becomes weaker, the calibration tone will not
deteriorate, but the operating time will decrease until the
time is too short to accomplish an adequate calibration.
When making a sequence of measurements, a calibration
check and an adjustment (if necessary) of the instrument
should be made at the beginning. At the end of the
measurement sequence, the calibration should be checked
again. The inaccuracy of the measurements will be at least
as large as the difference between the level measured for the
initial calibration (or calibration check) and the level
measured for the final calibration check.
Calibration History
Larson Davis strongly recommends that a history of each
calibration adjustment be kept for each piece of equipment.
Normally, most modern equipment requires little or no
adjustment once the initial calibration is performed.
Systematic drifts are possible, and these should be recorded
for corrective action.
Most Larson Davis sound level meters keep a history of each
calibration change that can be printed before an overall reset.
Please refer to the individual instrument manuals for details.
Environmental Precautions
While the CAL200 will perform normally under a wide
variety of gradually changing environmental conditions,