CR:270 Series User Manual
Page 6
First time use.
The instrument should be inspected for any signs of damage.
The two batteries type 6F22 (NEDA 1604 or PP3) should be fitted into the battery
compartment. See section 8 for details of changing the batteries.
Ensure that the MAX HOLD button is out. This is the lower of the three push buttons. If
this is not done, the display will be held. Push RESET ALL to ensure all functions are
reset to zero.
The lower of the four slide switches, WEIGHTING, should be pushed to the right hand
position marked dB(A).
The upper of the four slide switches, DISPLAY, should be pushed to the right hand
position marked SPL.
When using the CR:274 octave band instrument, the octave band filter may be enabled
when the instrument is switched on. Hold down the OCTAVE FILTER button for 5
seconds until none of the filter indicators are lit. See section 6. If so, the meter is ready
to calibrate and use.
Fundamental Precautions.
Always check the battery before and after each measurement. The CR:270 monitors the
battery continuously while operating.
Ensure that the black HOLD button is OUT. If this is not done, the display will not freeze
the last reading and the central colon will be displayed in the LCD.
Always check the instrument calibration before and after each measurement.
To obtain the most accurate readings, the microphone should be pointed at the source
of the noise and held away from the observer.
In wind over 5ms
-1
a foam windshield should be used. The UA:237 windshield should be
used with the CR:270. Do not operate the meter continuously at temperatures greater
than 40 degrees celsius or you will get errors of reading and the instrument may suffer
deterioration.
Remember to switch off after use or the batteries may leak and rot the case.
Never operate the unit in rain or snow. While the CR:270 is not affected by damp,
actual water in the microphone will cause errors of reading and may permanently
damage the capsule.
Keep the instrument still while measurements are being taken.
If the meter is being used out of doors, care should be taken to keep the unit away
from large objects which will cause sound reflections and thus give incorrect readings.
When the CR:270 is used inside buildings, thought should be given to the best site. If
in doubt make several measurements in different positions.
