Echelon LNS - Manual (Page 193)

LNS Programmer's Guide 179
break communication between the LNS Server and a remote Full client, the
NS#182
lcaErrNsInsufficientRtrsForNsi
exception will be thrown.
Using Dynamic Device Interfaces
As described in the Device Interfaces section in Chapter 6, each L ON W ORKS device
contains a device interface that represents the device’s functionality. The device interface
consists of network variables, configuration properties and LonMark Functional Blocks.
In LNS, network variables, configuration properties and LonMark Functional Blocks are
represented by NetworkVariable, ConfigProperty, and LonMarkObject objects.
The device interface as a whole is represented by the Interface object, which can be
accessed through the Interface property of the AppDevice object associated with the
device.
In some cases, there may be a need to modify the functionality provided by a device
interface. For example, some controller devices are used to control other devices. The
number of components required on a controller device’s interface is often an attribute of
the network configuration (i.e. how many devices it is controlling). Ideally, the resources
on these controllers could be allocated dynamically to fit the changing requirements of a
given network as devices are added to it. As a result, LNS Turbo Edition features
additional support for dynamic interface components, meaning that you can use LNS to
add custom interface components to devices that support dynamic interfaces. This section
describes how you can use those features.
Accessing a Device Interface
A device interface is represented by an
Interface
object. The
Interface
objects
contained by an application device include the device’s main interface, as well as custom
interfaces that have been added to the device dynamically. You can access the main
interface of a device through its Interface property. The main interface contains the
device interface installed with the device by its manufacturer, as well as all the network
variables and LonMark Functional Blocks defined in the custom interfaces that have
been added to the device. Main interfaces are static interfaces that cannot be modified
directly.
You can access and modify each of the custom interfaces that have been added to a device
through the device’s Interfaces property. Figure 8.4 shows the relationship between
the device’s main interface and its custom interfaces. Note that the network variables
and LonMark Functional Blocks included in the custom interfaces are also included in
the device’s main interface.