Echelon i.LON 100 e2 Internet Server - Manual (Page 68)

5.2.1.5 DataServerWrite
A data point's value and priority level are initially set when the data point is added to the
Data Server. The value is set to the value established for the property for
the data point, and the priority defaults to the lowest priority level (255).
You can use the DataServerWrite function to update the value and priority of one or more
data points at a time. Each NVL data point to be written to must be identified by an
element within the parameter, and each NVC data point must be identified by an
element. The rest of this section describes the information that must be filled in
within each of these elements.
You must reference the specific data point to be written to by their index numbers
(UCPTindex) or point names (UCPTpointName) within each of these elements.
If the data point is a structure, you can also specify the field whose value should be written
to by the function by filling in the property. In this case, you may also
want to fill in the property. If you assign the default value 1 to this
property, the change you make to the data point will be propagated to the network. If you
assign value 0 to this property, the change will be made in the i. LON 100 Data Server, but it
will not be propagated over the L ON W ORKS network. This may be useful if you are writing to
the different fields of a structure within a call to DataServerWrite, and do not want to
update the structure over the network until all fields have been written by the function.
The priority level specified for each data point is set by the property. This
must be a higher priority than that used by the last application to write to the data point. If
it is not, the data point will not be successfully updated. For more information on priority
levels, see Data Point Values and Priority Levels on page 3-5.
You can write to the value of the data point using either a value definition (UCPTvalueDef),
or an actual value (UCPTvalue). The example parameter below shows both of these
options. You should not attempt to write to more than 100 data points with a single call to
this function.
The following sample parameter writes to three data points. Note that the name of
each element within the parameter must match the data point type (NVL or NVC) of
the data point referenced within it.
Parameter
NVL_nvo01Switch
OffValue
25
5
state
1
50
0
i. LON 100 Internet Server Program 5-24 mer’s Reference