Message tag syntax, Keywords – Echelon LonTal Stack User Manual

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LonTalk Stack Developer’s Guide

177

// empty string initializer with its own

};

Message Tag Syntax

msg_tag [ connection-info ] tag-identifier [, tag-identifier ...] ;

Keywords

The connection-info field is an optional specification for connection options, and

includes the following keywords:

msg_tag

Declares a message tag with the specified tag-identifier.

bind_info ( options )
The following connection options apply to message tags:
nonbind

Specifies a message tag that carries no addressing information and does not

consume an address table entry. It is used as a destination tag when

creating explicitly addressed messages.

rate_est ( const-expr )

The estimated sustained message rate, in tenths of messages per second, that
the associated message tag is expected to transmit. The allowable value

range is from 0 to 18780 (0 to 1878.0 messages/second).

max_rate_est ( const-expr )

The estimated maximum message rate, in tenths of messages per second,

that the associated message tag is expected to transmit. The allowable value

range is from 0 to 18780 (0 to 1878.0 messages/second).

It might not always be possible to determine rate_est and max_rate_est. For

example, update rates are often a function of the particular network where the

device is installed. These values can be used by a network management tool to
perform network load analysis and are optional.
Although you can specify any value in the range 0 to 18780, not all values are
used. The values are mapped into encoded values in the range 0 to 127. Only the

encoded values are stored in the device's self-identification (SI) data. The actual

value can be reconstructed from the encoded value. If the encoded value is zero,
the actual value is undefined. If the encoded value is in the range 1 to 127, the

actual value is

5

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8

/

(

2

=

n

a

, rounded to the nearest tenth. The value a, produced

by the formula, is in units of messages per second.



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