4
2
O
VERVIEW
:
2.1
L
OGGER
D
EVICE
-
O
VERVIEW
Note: P and PCorr+ will both sometimes be referred to as
“device”,
“
logger
” or
“logger device”
within this document.
The P product family and PCorr+ product family are Leak Noise detectors built
by HWM. The equipment
’s primary
and repetitive function is to detect the presence of a
leak in a pipe network. The devices accomplish this by means of a specialised
microphone that can detect the sounds emitted from a leak. A micro-controller, built
into the unit, measures the noise level once per day and performs a statistical analysis
to generate a noise “histogram”. The re
sults are saved in memory for collection by the
user.
The saved data could be in the form of:
•
A
“
leak / no leak
” status
.
This gives a simple indication of whether the histogram indicates a
probable leak.
•
A Level / Spread indication.
This is a numeric summary of the noise histogram.
•
A “noise histogram”.
This provides a detailed indication of how consistent the noise measurement
is, and can be used for more advanced analysis.
•
An “Aqualog”.
This is a set of up to 28 histograms, made at regular intervals and used to
analyse the consistency of noise measurements over a longer period.
The name originally referred to a separate type of logger manufactured by
HWM, but this function has now been integrated into P / PCorr+
The logger devices are powered by non-rechargeable Lithium batteries. The software
within the logger is designed to take steps to minimise the battery use and thus
increase the life expectancy of the unit (e.g. the loggers are only active when needed;
most of the time they are asleep). The battery life is also affected by the user-
programable settings.
The stored data can be read from the loggers by means of communication over a
proprietary radio-link to a nearby device (the patrol equipment).
A version of P (referred to as AMR models) also have a built-in serial interface
for connection to certain types of meter-reading equipment; these can then wake the
logger and read its leak-state data using the wired connection.
PCorr+ products are an enhanced version of the P product. Most of the
functions are identical, but PCorr+ additionally allows a sound recording to be made.
