Echelon LonBridg Server - Manual (Page 59)

LonBridge Server User’s Guide 53
</nv>
The definition still lacks the network variable indices for the nviValue and
nvoValueFb network variables; see Browse the XIF File to Determine Indices on
page 56 to determine the indices.
The next step is to define the enumerations for the
state network variables.
Define <enum> Elements
The state network variables are structured network variables, and the example
LonBridge application for the simplified Lamp Module requires access to the
fields within these network variables. Thus, the <attribute> definition for each
<nv> element includes enum=”true” and a pair of <enum> elements. Each
<enum> element defines one state, “on” or “off”, and maps these values to the
network variable field enumeration values.
Thus, the <nv> elements for the
state attribute within the device class file
includes the following information:
<nv index="?" direction="input" size="3">
<byte index="0" length="1">
<attribute name="state" enum="true">
<enum input="off" output="?" />
<enum input="on" output="?" />
</attribute>
</byte>
<byte index="1" length="1">
<attribute name="state" enum="true">
<enum input="off" output="?" />
<enum input="on" output="?" />
</attribute>
</byte>
</nv>
<nv index="?" direction="output">
<byte index="0">
<attribute name="state" enum="true" scale="100">
<enum input="?" output="off" />
<enum input="?" output="on" />
</attribute>
</byte>
</nv>
The enumeration values are marked with a question mark (?). Also, for the input
network variable, the unknown values are the output values because the
LonBridge application uses the logical names; for the output network variable,
the unknown values are the input values.
To determine the enumeration values for the “on” and “off” states, return to the
Resource Editor, and expand the entry for Enumerations, as shown in Figure 8
on page 54.