Civil Engineering Reference
In-Depth Information
4.5.5.2
Communication Modes
• Silent: The Postmaster will be silent but still receives Letters and notifies the
Mayor when Letters are accepted. The Postmaster will transmit neither acknowl-
edgement bit nor error or overload frames.
• Listen Only: The Postmaster will be fully active but the Mayor will send Letters
only upon the King's request.
• Communicate: Normal communication.
4.5.5.3
City Mode
City-specific modes, e.g. configuration mode, service mode, working mode, etc.
For each City Mode the City Founder has to define how the City will work on Ac-
tion Mode and Communication Mode commands from the King.
4.5.6
Mayor's Document
Each Mayor has a Document with some Pages and an Envelope of his own by which
he can respond to the King. The King will broadcast a Base Number and the Mayor
will use the Envelope that equals the sum of the City Address and the Base Number.
The Mayor's Pages 0 and 1 are mandatory (Table
4.23
and
4.24
):
A City is fully identified by the Mayor's Page 1 and 2. Any King's Page can be
mirrored by a Mayor's Page and the current setup of a City can be checked by ask-
ing for those Pages.
4.5.7
City Organization
The City Founder (the module designer) always knows what information his City
must receive and what it can transmit in different situations but frequently he does
not know how his City will be used in a specific Kingdom. It is only known by the
Kingdom Founder (the system designer). A convenient way for the City Founder
to escape the problem of how to receive and transmit information is to leave it to
the Kingdom Founder. This is done by organizing the City information into Lists
where selectable information blocks are referenced by records. Lists are enumer-
ated from 0 to 253 and each list can hold up to 256 records. The King can use some
King's Pages to order the Mayor to construct new Pages by referring to records in
the Lists and place them in new Documents. In this way, modules can be optimized
to the system requirements and the use of bandwidth optimized as only required
data are transmitted. No profiles like the ones in CANopen and DeviceNet have to
be defined.
A full-blown City may have all of the following Lists:
