MK:427 Environmental Noise Microphone
Page 6 of 23
The standard version of the MK:427 has a 4-20mA current loop which outputs a current level,
expressed in milliamperes that is proportional to the sound level with either a 'Fast' or 'Slow' Time
Weighting. The choice of time weighting is a factory set option made at the time of purchase.
The MK:427 has, as standard, an electrostatic actuation system which allows for remote, automatic
and regular verification of the system performance to ensure accurate measurements. See the
Calibration section of the manual on page 12 for more details.
This manual details a version of the MK:427 with both the 4-20mA loop output and the electrostatic
actuator option fitted.
The output is always weighted with the ‘A’ frequency weighting which is the most commonly used
frequency weighting for the measurement of environmental and industrial noise levels.
The 4-20mA current loop output is ideal for integration to many process measurement and control
systems where your own system loggers and software can provide an accurate representation of the
'live' noise levels and also store data.
Your own interface system will need programming with a simple formula which is outlined on your
Factory Configuration Information sheet.
For Example:
For a unit with a range of 34 to 104 dB
Sound Pressure Level
dB = (10 x I)-10
(Where I is the output current in mA)
Therefore, in this example an output current of 7.23mA would represent a noise level, L
A
, of
62.3dB(A) as shown below:
dB(A) = (10 x 7.23) -10
dB(A) = 72.3 – 10
dB(A) = 62.3
Please check with our technical department if you need confirmation as to the settings of your
equipment or if you need any other technical guidance.
Tel:
+ 44 1733 667100
email:
