L-INX/L-GATE User Manual
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LOYTEC
LOYTEC electronics GmbH
7 Concepts
7.1 Universal Gateway
The operating principle of a universal gateway is to connect data points of one network
technology to data points of another technology. This is the primary function of the L-GATE
product family. Gateway function are, however, also available in the L-INX family.
Data points in the CEA-709 network are known as network variables (NVs). Data points in
the BACnet technology are known as BACnet server objects. They have a specific type (e.g.
analog input or binary output) and a set of properties, which describe the data point more
closely. The actual value is stored in the “Present_Value”. For more information on the
mentioned technologies refer to the LINX Configurator User Manual [2].
The typical task in configuring the universal gateway consists of the following steps:
1.
Selecting the data points of the network to be mapped (e.g., select the NVs in the
CEA-709 network nodes or create new NVs)
2.
Select or create matching counterparts of the other technology (e.g., create matching
BACnet objects)
3.
Create connections between the data points (e.g. connect NVs and BACnet objects).
The connection is the central part of the gateway functionality. It defines, which data points
are mapped to which data points. Refer to the Connections Section in the LINX Configurator
User Manual [2] for more information.
7.2 Data Point Configuration
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
using a folder structure. Folders can be created as needed and have a folder name and
description.
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 device provides a Web interface for displaying and modifying data point values (see
Figure 48). Data points that are structures contain their structure members as sub-data points
beneath them. Data point values are typically written by the controller or by the network. For
testing purposes the values can also be manually overridden (Set Override). More
information on the data point Web interface can be found in the LOYTEC Device User