Xylem System 5000 User Manual - Manual (Page 20)

18
The System 5000
™
takes a new approach to data logging. During setup, measurement
parameters are assigned logical names (labels) such as AirTemp or Battery. These names are
referred to as Tasks in the System 5000
™
. Each Task can be assigned an input or source, such as
an SDI-12 sensor or an A/D channel, as well as one or more outputs or destinations, such as a log
file or GOES transmission. The value retrieved from the input becomes the Task’s primary value
and will be passed along to any outputs assigned to that Task. In this manner, inputs and their
values can be easily identified by their Task names in both simple and more advanced setups.
The Concept of a Task
MANAGING TASKS
Time vs. Event-driven Tasks
The Manage Tasks screen is the primary
location for setup and configuration
of the System 5000
™
and is directly
accessible from the Main Menu. All Inputs
(measurements, calculations, etc) and
Outputs (recordings, transmissions, etc)
are configured through the creation and
use of Tasks on the system.
The left-most area shows the current
Tasks and the order in which they will be
executed upon each scan by the System
5000
™
.
Manage Tasks Screen
Most Tasks on the System 5000
™
will probably be set up and used based on a common scan
rate. If a scan rate of 15 minutes was chosen and all Tasks were setup as such, every 15 minutes
the desired Inputs would be measured and the Outputs would be run. These events are based
purely on the time of day and are most common in data logging applications.
Unique to the digital ports on the System 5000
™
is the ability to be event-driven rather than
time-driven. This means that if a digital port is assigned as the Input for a Task and designated
as Event-driven (based on the falling or rising edge), the Outputs for that Task would only be run
when the chosen port detected a falling or rising edge. A rain bucket, for example, that momentarily
closes a switch could be set as Event-driven with a log file as an Output. Every
time the rain bucket closes the switch, the date and time of the exact edge change would be
recorded.