Echelon LonBridg Server - Manual (Page 50)

44 LonBridge Device Class File
2. Define an <attribute> element for each abstract attribute that the
application requires.
3. Decide which network variables or fields within network variables the
LonBridge application needs to access. The application can include a
subset of the network variables or network variable fields that are
defined for the L
ON W ORKS device. Recommendation: If you define a
subset, include any mandatory network variables.
4. Define an <nv> element for each set of network variables or network
variable fields that correspond to each <attribute> element. The network
variables are defined within the L ON W ORKS device’s source files.
5. Use the NodeBuilder Resource Editor to determine the definitional
attributes of each network variable or field, such as its number of bytes,
type values, or enumeration values. You can also use the LONMARK
Resource Files Web page,
types.lonmark.org , to determine this
information.
6. Optional: Define <enum> elements for the attributes within an <nv>
element (inside the <nvs> element) to define logical names for network
variable or field values.
7. Browse the L ON W ORKS device’s external device interface (XIF) file to
determine the index value for each network variable. These index values
are required for each <nv> element.
Example for Creating a Device Class File
The following sections describe how to create a device class file for a simplified
Lamp Module, based on the Echelon Lamp Module. The example LonBridge
application for this simplified Lamp Module requires attributes for lamp state (on
or off) and for lamp power use.
Examine Source Files
For the Echelon Lamp Module, all network variable declarations are included in
a common header file that defines network variables, configuration properties,
functional blocks, and other Neuron C constructs (such as global variables,
functions, ISI callback functions, and so on).
The header file defines the following network variables. Note that the file defines
more network variables than the simplified Lamp Module will need.
///// Network Variables /////
network input SNVT_switch_2 nviValue;
network input SCPTenergyCntInit cp cpMinSendTime = 5;
// Set default throttle to 500ms
network output polled SNVT_switch_2 nvoValueFb
nv_properties {
cpMinSendTime
};
network output SNVT_occupancy nvoOccupancyFb;
network input far SCPTpwrSendOnDelta cp cpPwrSendOnDelta = 5;