6
•
Required for mobile phone app:
o
An internet connection (via the mobile network),
o
An account and password for the HWM DataGate system.
2.3
L
OGGER
D
EVICE
–
R
ADIO
-L
INK
The loggers are designed to conserve energy use wherever possible in order to prolong
the life of the battery, which is not rechargeable. The radio-link is one function affected
by this. The loggers do not continuously send data over the radio-link, but only do so for
part of the day; This
period is known as the “patrol window”. Typically, this will be up to
8 hours per day, during a time when data is planned to be collected by the user. The
rest of the day (and at times when measurements are being made) the radio interface is
turned off. During the patrol window, the logger transmits data typically every
2 seconds in order to ensure a patroller that is installed in a passing vehicle has
opportunity to detect the signal (usually several times) as it passes within the range of
the radio. Eac
h message is very short and is sometimes referred to as a “chirp”.
The loggers can sometimes be factory set into another radio mode, where the radio-link
has a “patrol window” of 24 hours
. To compensate for power use, the loggers transmit
chirps less frequently. Loggers with these settings can transmit to a fixed receiver
installed near-by.
This is sometimes referred to as “Fixed Network Mode”.
Some loggers can be factory set (or set by the user) to have no patrol window at all,
conserving energy even more. This setting is often used
for a logger being used as a “lift
and shift” device by the user.
Any time the logger device is not within its patrol window, it can have the radio-link
temporarily re-activated by resetting the logger (see section 2.5). This awakens the
logger’s radio
-link for a period of approximately 2 minutes.
The logger devices have to establish a 2-way conversation in order to download certain
types of data. To save power, the logger does not continuously listen for the Patroller
signal. It may therefore take typically up to 40 seconds for a device to begin the 2-way
conversation to allow data downloads to begin.
2.4
L
OGGER
D
EVICE
–
S
ERIAL
I
NTERFACE
In addition to the radio-link, some loggers (P AMR models only) have a wired
interface for connection to 3rd-party Automatic Meter Reading equipment. This allows
the AMR equipment to use the logger as an external leak noise sensor, collecting the
latest leak state result over the cable.
