User Manual

Network architecture
KNX architecture (ALN)
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R Repeater, e.g., LonWorks physical repeater
B Bridge, e.g., L-Switch (Loytec)
RT Router, e.g., LonWoks router
GW Gateway, e.g., PXC..., RXZ03.1
See
LonWorks networks Checklist (CA110335).
Trunk
A trunk holds all devices that can communicate with each other directly or via repeater, bridge or router.
The term trunk is specific to the Desigo system. One trunk corresponds to one LonWorks project. Trunks
can be connected via gateways.
Segment
A trunk can be divided into segments. The segments are connected by a router. If there are no routers, the
trunk comprises only one segment.
Physical segment
The physical segment is the communication medium. LonWorks devices are connected to the physical
segment. One segment can be divided by bridges or repeaters into several segments. The number of
devices per physical segment is limited.
System devices
Gateway
The gateway links trunks. It operates on the application layer of the ISO/OSI layer model. The following
LonWorks gateways are available:
The RXZ03.1 point coupler provides a fixed number and type of LonTalk network variables (NV). Each side
of the point coupler belongs to a trunk or LonWorks project. The point coupler can be used to implement
time-critical connections between two trunks. The point coupler integrates third-party devices that have
been engineered with a different tool.
Loytec L-Proxy and Sysmic XFM-LL are freely programmable point couplers. The XFM-LL device may be
used, when depicted like a standard third-party device (configuration via its own tool).
The PXX-L.. extension modules let you connect LonWorks devices to the PXC..D modular series.
Router
The LonWorks router operates on the network layer of the LonWorks protocol. It filters data packets based
on their subnet ID or group ID. Subnets or groups must never be defined across a router, that is, the subnet
IDs and group IDs at each end of the router must never be the same. Routers are used where there is
heavy local network traffic. They allow the unloading of unaffected devices from the network traffic. In
Desigo there are no large LonWorks networks, as the FLN is divided into trunks. Routers are only required
in exception cases.
L-Switch (Loytec)
The L-Switch filters the package on the basis of the subnet/node ID or group ID. It automatically learns the
topology and forwards the data packets accordingly. The L-switch does not have to be configured. Unlike
the router, there is no need to take account of any addressing limits (allocation of Subnet ID or Group ID).
Physical repeater
LonWorks has physical and logical repeaters. The physical LonWorks repeater does not filter the data
packets. It regenerates the electrical signal. One physical LonWorks repeater can be used in the path
between any two devices within a segment.
In logical repeaters, the data packet is processed by the neuron chip. This enables several logical repeaters
to be connected in series. The disadvantage is that the logical repeater must be configured, and that owing
to the limited size of the buffer, it cannot be used for large data packets, that is, for BACnet/LonTalk.
14.3 KNX architecture (ALN)
KNX is an open standard that conforms to EN 50090 and ISO/IEC 14543. See www.knx.org. KNX
corresponds to the former European Installation Bus (EIB) and is backward-compatible.
With KNX technology, advanced multiple disciplines and simple solutions can be implemented to satisfy
individual requirements in room and building automation in a flexible way. The ETS, a vendor-independent
tool is available for commissioning.