Echelon FTXL - Manual (Page 49)

FTXL User’s Guide 37
Sharing a Configuration Property
The typical instantiation of a configuration property is unique to a single device,
functional block, or network variable. For example, a configuration property
family whose name appears in the property list of five separate network variables
has five instantiations, and each instance is specific to a single network variable.
Similarly, a network variable array of five elements that includes the same
configuration property family name in its property list instantiates five members
of the configuration property family, and each one applies to one of the network
variable array elements.
Rather than creating extra configuration property instances, you can specify that
functional blocks or network variables share a configuration property by
including the static or global keywords in the configuration property declaration.
The global keyword causes a configuration property member to be shared among
all the functional blocks or network variables whose property list contains that
configuration property family name. The functional blocks or network variables
in the configuration property family can have only one such global member.
Thus, if you specify a global member for both the functional blocks and the
network variables in a configuration property family, the global member shared
by the functional blocks is a different member than the global member shared by
the network variables.
The static keyword causes a configuration property family member to be shared
among all elements of the array it is associated with (either network variable
array or functional block array). However, the sharing of the static member does
not extend to other network variables or functional blocks outside of the array.
Example 1:
// CP for throttle (default 1 minute)
SCPTmaxSndT cp_family cpMaxSendT = { 0, 0, 1, 0, 0 };
// NVs with shared throttle:
network output SNVT_lev_percent nvoValue1
nv_properties {
global cpMaxSendT
};
network output SNVT_lev_percent nvoValue2
nv_properties {
global cpMaxSendT // the same as the one above
};
network output SNVT_lev_percent nvoValueArray[10]
nv_properties
{
static cpMaxSendT // shared among the array
// elements only
};
In addition to sharing members of a configuration property family, you can use
the static or global keywords for a configuration network variable (CPNV) to
specify sharing. However, a shared configuration property network variable
cannot appear in two or more property lists without the global keyword because
there is only one instance of the network variable (configuration property
families can have multiple instances).
A configuration property that applies to a device cannot be shared because there
is only one device per application.