FIS HDL1, Operating Manual

Page: 10 / 55

- 2 -
SENSORS
The data logger provides dedicated connections for four SDI-12 sensors and a
standard FTS tipping bucket style rain gauge.
TELEMETRY
The HDL1-G5 is factory configured with an integrated high data rate GOES
Transmitter. The HDL1 is factory configured with an external telemetry connector
which can connect to a variety of FTS telemetry products.
DISPLAY
Both data loggers come with a built-in weatherproof display unit as well as a standard
PC com port connector.
ENVIRONMENTAL
The data logger is watertight, even with no connectors attached. With the exception
of the front panel COMPUTER connector, all the connectors used are circular metal
shell military types that have both color coding and unique sizes and pin-outs that
minimize erroneous connections. The COMPUTER connector is a stainless steel
DB9 com port for easy connection to a local PC.
DATA STORAGE
The data logger actually stores four separate items: the data logger program (DLP);
the data; an audit log; and, telemetry configuration information. Each item is
described further below.
All data logger storage is in non-volatile memory. This means that collected data,
program configuration, and the data logger program are preserved through power
failures and that no backup batteries are needed. If satellite telemetry is used, the
setups for the satellite interface are also saved and are restored when power is
restored. Password protection can be enabled to limit access to functions such as
clearing memory, etc.
DATA
Storage for more than a year of field collected data (typically 87 000 data records).
Data is stored in a compressed form, with time tags on each record. This is a
circular buffer, so the newest data overwrites the oldest when the memory fills. The
time tags have a resolution of one second and correctly account for leap years.
The data is cleared whenever a new program is loaded. It is possible to explicitly
clear the data; this would be recorded in the audit log.