Specifications

HYDROLOGICAL SERVICES
DL3 100-041 IMP
Issue 2: 15/11/2005
average current drain = [(1.7% X 155 mA )+ (98.3% x 200 uA)] 100 = 2.83 mA
continuous
Power = 12 v (nominal supply) X 2.83 mA = 34 mW
Notes:
1. For an RRDL-3 connected to a TBRG and Shaft encoder, each rain, river or 6 Hr internal
housekeeping event, wakes the logger for approximately 20 mS at 75 mA current drain.
With 100 events daily, the added power consumption is negligible, approximately 2 Mw.
2. A 1AH battery could provide sufficient energy to run the station for 350 hours or 2 weeks
without recharge.
3. The battery, modem, and logger could fit within the internal dimensions of a TBRG. The
external surface area of the TBRG could house a flexible solar array of sufficient capacity
to charge the internal battery.
4. The dial out capability of the logger will increase power consumption when compared to
polling for the same data. This is due to the logger and modem consuming power during
the call set-up and clear sequence.
5.1.7 System Memory
A fundamental requirement of the logger unit is for sufficient memory capacity to store 45,000
events, time stamped to one second resolution, plus the additional overheads of periodic time and
date checks. The figure of 45,000 is representative of 9.5 metres of rainfall where each event
equals 0.2 millimetres, and satisfies the maximum expected annual rainfall for a location within
Australia.
In most cases the logger unit can be returned to the processing centre via surface mail. The
loggers small size and light weight means the package returned, conforms with low cost postage
tariffs.
The logger application requires three essential memory areas, Data Memory for storage of the
historical records, Program Memory for storage of the application software and Set-up
Memory to store unique station parameters.
The memory arrangement is as follows:-
Data Memory - re-usable, non-volatile Flash memory (100,000 write / erase cycles);
Program Memory - the application software is also contained in Flash memory which
allows for the unique feature of downloading new software remotely;
Set-up Memory - E²PROM for storage of user set-up parameters with 100,000 write
/ erase cycles.
5.1.8 System Clock
The clock performance in terms of reliability and maintainable accuracy is of prime importance as
the historical rainfall record is unusable should time and date errors occur. The clock maintains