Echelon LNS - Manual (Page 196)

LNS Programmer's Guide 182
and message tags to the new
Interface
as you desire, provided that the
device supports them. For more information on these tasks, see the
following sections.
Adding LonMark Functional Blocks To a Custom Interface
A LonMark Functional Block represents a collection of network variables and
configuration properties on a device that perform a related function. For example, a
digital input device with four switches could contain one LonMark Functional Block for
each switch. For general information on LonMark Functional Blocks, and how you can
use them to configure and manage a device, consult the LonMark Interoperability
Guidelines, which can be downloaded from the web at
http://www.lonmark.org/products/guides.htm .
In LNS, LonMark Functional Blocks are represented by LonMarkObject objects. Some
custom device interfaces support dynamic LonMark Functional Blocks, which means that
you can add them to the interface manually. You can determine if an interface supports
dynamic LonMark Functional Blocks by reading the interface’s
DynamicLonMarkObjectCapacity property. If the device interface supports dynamic
LonMark Functional Blocks, the DynamicLonMarkObjectCapacity property will be set
to a value greater than 0. Note that you cannot add LonMarkObjects to a device’s main
interface, although the DynamicLonMarkObjectCapacity property of that Interface
may be set to a non-zero value.
To add a dynamic LonMarkObject to a device, follow these steps:
1. Access the custom interface that you want to add the LonMarkObject to.
If necessary, create a new custom interface, as described in Adding a
Custom Interface to a Device on page 181.
Dim Interfaces as LcaInterfaces
Dim MyNewInt as LcaInterface
Set MyInterfaces = MyAppDevice.Interfaces
Set MyNewInt = MyInterfaces.Item(“NewInt”)
2. Make sure that the interface supports the addition of dynamic
LonMarkObject objects by reading the Interface object’s
DynamicLonMarkObjectCapacity property. If it does, acquire the
Interface object’s LonMarkObjects collection.
Dim LonMarkFunctionalBlocks as LcaLonMarkObjects
Set LonMarkFunctionalBlocks = MyNewInt .LonMarkObjects
3. Call the Add() method on the LonMarkObjects collection to create a
new LonMarkObject object. The Name and ProgammaticName
properties of the new LonMarkObject object will be set to match the
name you specify as the fbName element. You should note that the name
assigned to the LonMarkObject objects on each device must be unique. If
you attempt to use a name that is already used on the device, the
operation will fail, and the LCA#3 lcaErrDuplicateKey exception will
be thrown.
Dim MyLMFB as LcaLonMarkObject
Set MyLMFB = LonMarkFunctionalBlocks.Add(“new LMFB”,500)