Reference Datapoints - Honeywell Centraline FALCON User Manual

USER GUIDE FALCON
Value datapoints are values (intermediate results and parameters) computed while
the application program is running. In contrast to physical datapoints, value
datapoints are not directly connected to hardware devices.
A typical example of a value datapoint is a room temperature setpoint.
Access via datapoint name During system operation, you may need to access these values. To simplify this
process, you can include value datapoints in the datapoint list, where you can
access them directly via their datapoint name.
Like physical datapoints, value datapoints, too, can have different properties; for
example, they can specify a manual value, set minimum and maximum values, or
log trends.
The following are types of value datapoints:
• Analog value points
• Binary value points
• Multi-state value points
Analog Value Datapoints Analog value points are software points containing an analog value in the user
program.
An analog value point could, for example, contain a flow temperature setpoint cal-
culated from the room setpoint and the outside air temperature via the heating
curve.
Binary Value Datapoints Binary value points are software points containing a binary value in the user
program.
For example, logical AND operation:
The AND operation provides a logical 1 output when all input conditions are also
logical 1. Otherwise the output is a logical 0. If the user program contains such an
AND operation on different input conditions, then the output could be available as a
binary value datapoint.
Multi-state Value Point Multi-state Value datapoints allow switching 32 stages (including the "off stage") of
physical digital inputs or outputs. Depending on the number of stages, the multi-
state value point provides up to 32 editable stage texts, e.g., stage 1, stage 2, stage
3, etc, to be edited in CARE.
A typical example would be a multi-state electric heater or a multi-stage fan.

Reference Datapoints

If your control and monitoring system contains more than one controller, the con-
trollers communicate with one another via the BACnet bus. This enables one con-
troller both to read and set the datapoints from other controllers, and to read values
rd
of 3 -party BACnet devices of the project and external BACnet devices which are
not in the project.
This data communication is realized via so-called reference input/output points.
They always originate in or write to another plant and may originate in or write to
another controller.
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