L-VIS User Manual 176 LOYTEC
Version 6.2 LOYTEC electronics GmbH
10 Data Point Configuration
As outlined in the description of the data point object in section 9.5.11, the network
variables, BACnet server objects, client mappings, user defined registers, and system
registers are represented by objects which exist on the device independent of any controls
or other objects in the object tree. These objects are called data points and are referenced
through the L-Vis data point objects described in section 9.5.11 by their unique ID.
While some of these objects are created automatically, most of the data points need to be
created by the user. There are ways to manually create individual data points, import object
definitions from CSV files or scan the network and create new data points based on the
information collected by the network scan. Once created, a data point may be used to
exchange data with other devices on the network, store and load internal registers, or access
internal system parameters. Working with data points is the same for the entire line of
LOYTEC products.
This chapter explains the use of the data point system on which L-Vis projects are built.
10.1 Data Points
10.1.1 Overview
Data points are part of the fundamental device concept to model process data. A data point
is the basic input/output element on the device. Each data point has a value, a data type, a
direction, and a set of meta-data describing the value in a semantic context. Each data point
also has a name and a description. The entire set of data points is organized in a hierarchy.
At the data point level, the specific technological restrictions are abstracted and hidden
from the user. Working with different technologies at this level involves common work-
flows for all supported technologies.
The direction of a data point is defined as the “network view” of the data flow. This means,
an input data point obtains data from the network. An output data point sends data to the
network. This is an important convention to remember as different technologies may define
other direction semantics. If a data point can both receive and send data on the network, its
direction is set to value, indicating no explicit network data flow.
The basic classes of data points are:
Analog: An analog data point typically represents a scalar value. The associated
data type is a double precision machine variable. Meta-data for analog data
points include information such as value range, engineering units, precision, and
resolution.
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