Cirrus CR:270 Series, User Manual

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CR:270 Series User Manual Page 4
Overview.
The CR:270 series of instruments is a range of Digital Integrating Sound Level Meters.
The instruments in the range are:
CR:271 Type 1 Integrating Averaging Sound Level Meter
CR:272 Type 2 Integrating Averaging Sound Level Meter
CR:273 Type 1 Integrating Averaging Octave Band Sound Level Meter
CR:274 Type 2 Integrating Averaging Octave Band Sound Level Meter
This manual will refer to the CR:27x where the features are common to all the
instruments listed above. Where there are differences between both the specification
and operation of any of the instruments, these will be stated with reference to the
particular instrument.
The CR:270 series have all the features necessary to make a wide variety of Industrial
noise measurements, and they comply with the Standard IEC 804 (BS 60804) for Inte
grating Averaging Sound Level Meters, conventionally called 'Leq Meters' and IEC 651
(BS 60651) for Sound Level Meters, meeting both these specifications to Type 1 and
Type 2 accuracy where applicable. The CR:273 and CR:274 instruments also features
octave band filters that meet or exceed the requirements of IEC 1260.
The CR:270 series of instruments are ideally suited to the following uses:
 Determination of Leq for assessment of hearing loss risk.
 Measurement of machine noise.
 Sound Power Level measurements by the survey method.
 Specification of hearing defenders using the octave band method (CR:274 & CR:273
) or HML method (CR:272 & CR:271)
 Measurement of the absolute peak of a signal.
 Measurement of the 'Peak' action level under the EC directive.
Recommended Accessories
A full range of accessories are available for the CR:270 Series. These include the
following:
Item Description
CR:513A
Acoustic Calibrator
UA:237 Windshield
CK:250 Attache Case
CP:22 Pouch
These accessories can be purchased at a later date. The attache case allows the sound
level meter, acoustic calibrator, windshield and miscellaneous accessoires to be
transported safety.
Please refer to the current Cirrus Research pricelist for full details of the accessories
available for the CR:270 series of instruments.