User Manual

Network architecture
BACnet architecture (MLN & ALN)
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The half-router function is implemented in Desigo CC, XWP/ABT and PX.
PTP connections are only possible between Desigo CC, XWP/ABT und PX. PTP
connections between PXs are not permitted.
PX devices which can be reached via PTP always belong to a separate site.
With reference to the topology at the beginning of the chapter, the site named
Baar must not be combined with the sites named Zug or Cham. Several PXs per
site can be used as half routers. When establishing a communication, the best-
performing connection is always selected. Redundancy is not allowed, that is,
several simultaneously active connections in a given BACnet network are not
allowed.
With Desigo CC, a separate, independent, internal BACnet internetwork is
created for each Data Link Layer type. Routing between LonTalk, IP or PTP is
therefore not possible.
The following parameters are required for each half router:
Designation Description
Local network number The BACnet network number to which the half router belongs.
With PX, the local network number is the same as the device's own network number.
Desigo CC supports all three different Data Link Layers (IP, LonTalk and PTP). They are
handled internally as independent BACnet internetworks. This means that routing between
the different Data Link Layers is not possible. Therefore, the local network number can be
allocated to IP and/or LonTalk independently of the networks. However the local network
number must be unique among all networks which could possibly be reached from Desigo CC
via a PTP connection.
Recommendation:
If Desigo CC has an additional Data Link Layer (IP and/or LonTalk), the local network number
of this network should be used (example in the beginning of the chapter: For Desigo CC 2, the
local network number of BACnet network #4 should be adopted).
In Desigo CC with only one PTP connection, the local network number must be in the range
1000 to 1099. (Example: Desigo CC 3 -> #1000).
COM parameter For the PX half router, the COM port to which a modem or null modem is connected must be
specified.
Modem parameters The modem parameters contain individual settings for the relevant modem types. Predefined
parameter sets are available for the PX half router.
The following parameters are required for each PTP connection starting from a
PX half router:
Designation Description
Remote network number This network number determines the BACnet network in which the remote partner device is
located. In the Desigo system this is the local network number of Desigo CC.
Remote area name The remote area name stands for a peer-to-peer remote network number of the network
containing Desigo CC.
During configuration, the remote area number lets you assign a clear name to the (remote)
alarm recipient rather than a network number.
Telephone number The telephone number for access to the remote device.
Performance index The performance index refers to the quality of the router data connection. If multiple PX half-
routers are available in a PX site, and if a connection to a remote network is to be established,
the router with the best performance index is selected. If no connection is established, the
router with the next best performance index automatically tries to connect.
Range: 0...255 (0= best / 255 = worst connection)
Application Layer
Network Layer
PTPIPLonTalk MSTP