230 • LON

General

LON nodes can be flexibly networked by one or several transmission media, such as for instance a twisted pair of conductors ("Twisted Pair"), the 230V power supply or radio and freely communicate among each other. Modifications and maintenance work such as extensions using high capacity tools and components by now available on the market, are possible at any time and while the system is in operation.

As such, LON offers a consistent and particularly economical and fast solution for simple and more complex automation tasks.

5.1 General Safty Information!

Warning!

Prerequisite for the observance of the intended use of the hardware and/or software is compliance with the generally accepted technical rules and standards. The user must observe the safety and accident prevention regulations applicable for the individual application. Here special emphasis must be placed on measures intended to protect from indirect electrical shock.

Beyond the regulations generally applicable, further rules might become relevant pursuant to the actual application, such as safety or elevator systems.

Where automation solutions are realised with the hardware and/or software which in the event of a malfunction could cause injury or major material damage, the user has to take suitable external and independent measures to ensure a safe operation of the system even in fault situations.

Such measures could, for instance include the use of forcibly opened safety limit switches which lead to a controlled or uncontrolled disconnection of the energy supply to machine drives.

Modular I/O System

LONWORKS®

LON • 231

Information on the network architecture

5.2 Information on the network architecture

Attention

Please note the following information intended to place emphasis on measures to be used to allow a reliable and trouble-free communication especially in networks of the Lonworks technology.

•Make sure that the specifications regarding transceiver, network topology, network lengths and cable specifications etc. are adhered to.

•Select the installation location of the components such that the ambient temperature range tolerated by the components are observed and that any heat produced can be dissipated.

•Allow a 200 mm minimum spacing from high energy interference sources, e. g. frequency changers.

•Prior to connecting individual components, check whether the operating voltage corresponds to the parameters on the machine type plate. Please pay particular attention to the fact whether direct current and/or alternate current supply is possible or whether a particular polarity of the supply voltage has to be observed.

•Mixing up the connections for data and current supply can lead to the destruction of components!

•On the basis of the documentation supplied, please obtain information as to which connections are coupled and/or what potential differences are permissible between connection points (e.g. signal mass, operating voltage).

•Please note that the removal or addition of network components during the running network operation implies risks relating to the data transmission and destruction of components.

•Should you fit coupling elements in the network, such as routers, repeaters, etc., make sure prior to connecting these coupling elements that conflicts are excluded.

Modular I/O System

LONWORKS®

232 • LON

Network architecture – Principles and Regulations

5.3 Network architecture – Principles and Regulations

A locally operating network is designed on the basis of an intelligent fieldbus node, one DC 24 V power supply unit and a PC with an installed Network Management Tool Software.

A XLON®DONGLE Lon-Talk® Adapter (Item no.: 759-344) can be fixed on the PC's parallel port as an interface to the bus. A connection cable is included in

the XLON®DONGLE delivery.

Every fieldbus node consists of a fieldbus coupler/controller at the front end, a number of I/O modules and an end module which is placed at the other end. The connection between the I/O modules and the coupler/controller is made automatically when snapped onto the DIN rail.

The internal bus includes the internal communication between them.

Physical 62 digital I/O modules can be connected to one LON fieldbus coupler/controller.

Sensors and actuators are connected on the fieldside to the digital or analog I/O modules. They are intended to ensure the coupling of the digital, analog or serial sensors and evaluate their signals.

In the initialization phase the fieldbus coupler/controller determines the physical structure of the node and creates a process image from this with all inputs and outputs. This could involve a mixed arrangement of analog (word by word data exchange) and digital (byte by byte data exchange) modules.

The fieldbus communication between network management application and fieldbus-coupler/controller takes place via network variables.

The coupler is equipped with a special micro-controller for signal processing, the so-called Neuron chip. Depending on the application for signal processing, this Neuron chip contains an individual program written in the programming language Neuron C.

Modular I/O System

LONWORKS®

LON • 233

Network architecture – Principles and Regulations

Thanks to convenient WAGO plug-ins, such as TOPLON® IF which includes some typical building automation functions or TOPLON® PRIO which enables easy data assignment to network variables, ready made application functions are available to you.

If you want to program your own special Neuron-C application, you can use a set of functions from the WAGO Neuron-C function library. This library provides important basic functions for operation with a control system, such as reading of digital inputs and analogue inputs and writing of digital and analogue outputs. This makes programming much easier.

More information

i Please find some detailed information about plug-ins, function libraries and updates on the Internet at:

http://www.wagotoplon.com

The results of the Neuron°C application are transmitted to actors or via the fieldbus to other nodes in the form of messages.

62 digital 4 channel modules, max. 60 analog 2 channel modules or 40 analog 4-channel modules respectively can be connected to one LON fieldbus coupler programmed with an application in the Neuron°C programming language.

5.3.1 Transmision media

In the network architecture the LON nodes are connected by means of a message transmission medium. Access of a LON node to the transmission medium is made possible by a transceiver. This transceiver greatly depends on the individual transmission medium. With LON, the corresponding transceivers are able to support a large number of transmission media, e. g.:

•twisted pairs (e.g. via transceiver FTT-10A)

•power line (e.g. via transceiver PLT-21)

•Radio connection (e.g. via transceiver LF 433MHz)

•Infra-red

•Coax cable

•Fibre optic cable

With the use of different transmission media with different bit rates in one network, coupling elements, the so-called routers, permit the transmission of messages from one medium to the other.

The most widespread type of wiring in buildings is the twisted pair wiring. In addition to being low priced and easy to handle, it allows wiring as a bus with only one matching resistor. Even a ringor star-shaped wiring as well as any

Modular I/O System

LONWORKS®