Echelon FTXL - Manual (Page 59)

FTXL User’s Guide 47
http://global.ihs.com/doc_detail.cfm?item_s_key=00391891&item_key_date=9711
31&rid=CEA .
See Appendix E, Determining Memory Usage for FTXL Applications , on page
181, for information about how to calculate the memory requirements for you
FTXL application.
Address Table
The address table contains the list of network addresses to which the device
sends network variable updates or polls, or sends implicitly-addressed
application messages. You can configure the address table through network
management messages from a network management tool.
By default, the LonTalk Interface Developer utility calculates the size of the
address table. The utility calculates the required number of address table entries
based on parameters defined in the device’s interface, such as the number of
static polling input network variables, static non-constant output network
variables, bindable message tags, the number of aliases, and the number of
dynamic network variables. The utility always allocates at least 15 address table
entries. Within the LonTalk Interface Developer utility, you can override the
automatic calculation of the table size and specify any number of entries, from 0
to 4096.
Recommendation: Whenever possible, use the LonTalk Interface Developer
utility-generated size for the address table.
The maximum number of address table entries that a device could require is
determined by the expected maximum number of different destination entries
that the device requires for connections (network variables and bindable message
tags).
The size of the address table affects the amount of RAM and non-volatile memory
required for the device. When the LonTalk Interface Developer utility calculates
the size of the address table, it attempts to balance the need to limit the amount
of resources required (small address table) and the need for comprehensive
coverage (large address table). Although you generally do not need to, you can
override the automatically calculated value with one that reflects the use of the
device.
Alias Table
An alias is an abstraction for a network variable that is managed by network
management tools and the FTXL LonTalk protocol stack. Network management
tools use aliases to create connections that cannot be created solely with the
address and network variable tables. Aliases provide network integrators with
more flexibility for how devices are installed into networks.
The alias table has no default size, and can contain up to 8192 entries. The
LonTalk Interface Developer utility calculates the size of the alias table. The
utility calculates the required number of alias table entries based on parameters
defined in the device’s interface, such as the number of static network variables
and the number of supported dynamic network variables. The utility always
allocates at least 5 alias table entries, unless the device does not support any
network variables. Within the LonTalk Interface Developer utility, you can