Echelon i.LON 1000, User Manual, Page: 85 / 126

i .LON 1000 Internet Server User’s Guide 10-13
Important! The default value of the PROPAGATE: attribute is FALSE when operating on a
network variable field. For further information, see PROPAGATE : .
FORMAT:
You may assign a format to a network variable to control how the data is displayed and
changed in your web page. Specify the format of the network variable using the FORMAT
attribute.
Network variable formats can come from three places:
LonMark Standard Network Variable Type (SNVT) Device Resource Files
This is a set of files that describes the data structures within SNVTs and also describes the
formats to be used for display of SNVT data. On the
i. LON 1000, these files may be found in
the directory
/root/lonworks/types
, and are named
STANDARD.ENU
,
STANDARD.TYP
,
STANDARD.FMT
and
STANDARD.FPT
.
The default format for a SNVT is its native format, as described in the
STANDARD.FMT
text
file within the resource file set. To assign a different SNVT format, or to assign a SNVT
format to a user network variable type, explicitly assign the format type. For example:
FORMAT:SNVT_switch
User Network Variable Type (UNVT) Device Resource Files
This is a set of files created by device manufacturers to describe non-standard network
variables. Using the same mechanisms as the standard resource files, they describe how to
format data from a particular manufacturer's device. On the
i. LON 1000, all device resource
files will be found in the directory
/root/lonworks/types
.
UNVT formats must be specified using a fully qualified format name of the form:
#<progID>[<selector>].<format name>
In this syntax, the “
#
”, “
[
“, “
]
” and “
.
” characters are literal characters. The program ID is
represented as a hex byte string (in the “
RAW_HEX_PACKED
” format described below). The
selector is a one-digit string from 0 to 6, and the format name syntax is similar to that used
for SNVT types, except that the type name starts with “UNVT” instead of “SNVT”. For
example:
FORMAT:#8011223344556677[1].UNVT_switch
Built-in Formats
Built-in formats are provided by the underlying formatting engine, and they include "
RAW
",
"
RAW_HEX
”, and “
RAW_HEX_PACKED
”. All of these formats display the network variable data
byte-by-byte, in the same order that the bytes arrive on the network (the Neuron has Big
Endian byte ordering, the opposite of the PC’s Little Endian ordering, and network variable
data must be in Big Endian order on the L
ON
W
ORKS
network). The “
RAW
” format displays
the data as decimal byte values, with each byte separated by a space. The “
RAW_HEX
” format