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  Related Information

Device Certification - LonMark conformance instructions.

Design Guidelines - Technical information for developing open interoperable LonMark products.

Technical Corner - Provides answers to commonly asked technical questions.

LonMark Members who manufacture products used in Open Systems

Terminology (J - L)

The descriptions and terminology contained within this document are made in the context of use with LonWorks® networks and products.




An aspect of a drawing that can be turned on or off. Each drawing contains three layers: physical, logical and data whose default setting is “View” or being displayed. The physical layer shows all devices, routers, channels, and subsystems on a page. The logical layer contains all functional blocks, message tags, network variables, unmonitored connections, and subsystems on a page. The data layer contains all monitored connections on a page. Click on a given button in the toolbar to show or hide the associated layer. Hiding layers that aren’t required for viewing allows the user to reduce the clutter in a drawing.

LCA (see LonWorks Component Architecture)

LCA Data Server API

A standard LCA component that provides high performance monitoring and control. Using the data server, client applications can observe the values of network variables and explicit messages and can change the values of network variables or send explicit messages to effect the operation of the network. The data server supports both bound and unbound monitoring (using polling) and, optionally, filters redundant updates so that only changes in a variable’s value are reported to the application. To simplify client applications, the data server optionally converts raw network data into formatted text strings, which can be directly displayed.

LCA Field Compiler API

An optional LCA component, which can be used to build tools that can be used to reprogram devices in the field. This API consists of Dynamic Link Libraries for a Neuron C compiler, assembler, linker, exporter, and debugger.

LCA Object Server ActiveX Control

An ActiveX control that converts LNS objects (e.g., devices, routers, channels) managed by the NSS for Windows engine into standard OLE objects. The object server also provides a network tool kernel that enables sharing of information and objects between multiple tools and components. The kernel also provides an extensible host database that contains host-specific data not managed by the NSS as well as application-specific data.

Legacy I/O Device

A sensor or actuator, which cannot directly attach to a LonWorks network.

Lightweight Client (see Remote Lightweight Client)

Link-Powered Device

A device that is powered by a central power supply connected to the network.  This power supply is typically shared by several devices on the network, eliminating the need for a power supply at each device. The power is supplied over the same medium as the communication signals.

LNS® (LonWorks Network Services)

Echelon Corporation's LNS provides directory, installation, management, monitoring, and control services required for open LonWorks networks. LNS is a platform that allows multiple LNS applications to interoperate on the same personal computer (PC) or on multiple PCs on the same network. See also LonWorks Network Services.

LNS is a client-server operating system with a single LNS Server that supports many interoperating client applications. The LNS Server can run as a standalone application on a PC attached to the network, or it can run on the same PC as the Network Management tool. Clients on other PCs (called remote clients) can log into the LNS Server to access the shared LNS database.

Since API networks operate as a peer-to-peer network and use a different database structure (vs. client-server), the networks are incompatible. This implies that API products cannot be commissioned using an LNS tool and visa versa.

Network Management tools use the client-server capabilities of LNS to allow multiple Network Management tools running on different PCs to simultaneously access the same LNS Server. This capability allows multiple users to work at the same time on a single network.

LNS Client

Any application that uses the services of the LNS Server.

LNS Host Application

A host application that uses an NSI as its network interface. An LNS host application can make use of the services, events, and properties provided by an NSS to perform network installation, configuration, maintenance, repair, monitoring, and control. A LNS host application can also implement its own application-specific services, events, and properties and, through the LNS architecture, make these available to other LNS host applications.

Load Status

The application state of the target device. The load status is indicated in the NodeBuilder Device Window and the Neuron C debugger status bar. A device may be in one of the following load states: applicationless, configured, or unconfigured.

Local Client or Local Full Client

A Network Management tool running on the same PC as the LNS Server. The simplest Local Client configuration, a local application is where the Network Management Tool and LNS Server PC is directly connected to the LonWorks Channel.

Local IP Client

The other configuration for a local client is as a Local IP client.

LonMark® Logo

A distinctive logo applied to LonWorks devices that have been certified to the interoperability guidelines of LonMark  International.

LonMark Affiliate

A Regional or National chapter affiliated with LonMark International. Click here for a full listing of Affiliates.

LonMark Certified

A LonMark certified device has a program ID type 8 (LonMark certified) or 9 (non- LonMark certified). In these cases each functional block will correspond to a LonMark object. A non-LonMark certified device will contain just one functional block, known as a virtual functional block, which represents all of the network variables and configuration properties on the device.

LonMark Device

A LonWorks device that has been certified to meet the interoperability standards of LonMark International.

LonMark Functional Profile

A LonMark functional-block definition or template. Such "Profiles" are designed for specific application areas, such as HVAC or lighting systems. An example is the VAV Controller functional profile, which takes room temperature value from the network and implements a PID control algorithm to drive a damper actuator to regulate room temperature. LonMark International forms task groups of interested members to design, approve, and publish functional profiles in numerous functional areas, such as HVAC, security, lighting, and semiconductor manufacturing systems.

LonMark International (LMI)

An independent organization of companies, organizations and individuals committed to the development, manufacture, and use of interoperable LonWorks products and networks.

LonMark Functional Block (formerly: LonMark Object)

A collection of network variables, configuration properties, and associated behavior defined as part of the LonMark interoperability program. LonMark objects define standard formats and semantics for how information is exchanged between devices on a network.

LonTalk® Firmware

A program implementation of the LonTalk protocol residing in ROM in the processor chip of every LonWorks device. A portion of non-volatile RAM in the device is reserved for modifiable configuration parameters to make tradeoffs in performance, security, and reliability for a particular application.

LonTalk Protocol

The protocol used on LonWorks networks to standardize communication.  It defines a standard way for devices to exchange information.

LonTalk Router  (see LonWorks Router)

LonWorks Component Architecture (LCA)

Echelon Corporation's LNS application programming interface for Microsoft Windows hosts.  LCA is an architecture for implementing LonWorks network tools using multiple cooperating software components.  LCA provides an open standard with a standard network tool kernel, so that tools may be constructed from software components from multiple vendors.  LCA defines a standard Windows OLE service interface for invoking network services and a standard application interface for invoking LCA software components.

LonWorks Control Device

A LonWorks device that senses and/or controls the variables in the system being controlled. It can have any combination of embedded sensors and actuators, or input-output interfaces to external legacy sensors and actuators. The application program in the device can both send and receive values over the network and perform data processing (e.g. linearization, scaling) of the sensed variables and control logic such as PID loop control, data logging, and scheduling.

LonWorks Control Network

Network of intelligent devices (such as sensors, actuators, and controllers) that communicate with each other using a common protocol over one or more communications channels.

LonWorks Device

A device that communicates on a LonWorks network. A LonWorks device may be an application device or a router. LonWorks devices are commonly called devices or nodes in LonWorks documentation. Each LonWorks device includes local processing and input/output (I/O) hardware to process input data from sensors, execute a control task, and control actuators. Each device also includes the capability to communicate with other devices using the LonTalk protocol in firmware. The LonTalk protocol is a complete 7-layer communications protocol that ensures that devices can interoperate using an efficient and reliable communications standard.

Each LonWorks device contains an application program and hardware similar to the following:

  • A Neuron Chip or other processor that can run the protocol.
  • A transceiver.
  • Application electronics to connect the Neuron Chip to I/O devices such as sensors, actuators, displays, and keypads.
  • An optional host processor. If a host processor is used, the application executes on the host processor and the Neuron Chip or other processor is used as a network interface.

A LonWorks Router is a special type of LonWorks device.

LonWorks Network Services (LNS®) Architecture

The foundation for interoperable LonWorks installation, maintenance, monitoring, and control tools.  Using the services provided by the LNS architecture, tools from multiple vendors can work together to install, maintain, monitor, and control LonWorks networks.

LonWorks Node  (see LonWorks Device)

LonWorks Router

An active LonWorks device, which physically connects two LonWorks channels.  Each router side can receive a packet, make a decision as to whether the packet needs to be transmitted, and transmit the packet on the other side’s channel, if required.  The router necessarily injects some delay in the packet transmission.

A router can be configured to be one of the following:

  • Repeater:  all packets are forwarded.
  • Permanent Repeater:  all packets are forwarded. Subnets can span permanent repeaters.
  • Bridge:  all packets in a given domain are forwarded.
  • Permanent Bridge all packets in a given domain are forwarded.  Subnets can span permanent bridges.
  • Learning Router:  packets are routed only for a given domain.  The router starts as a bridge and reduces forwarding as it learns the topology.  Learning routers are vulnerable to failures if configured devices are incorrectly moved within the topology.
  • Configured Router:  packets are routed only for a given domain.  Configured routers forward packets based on configured tables.  This is the most reliable and efficient form of router.

Each router side can be addressed by its Neuron ID or by a subnet/node address.  The side of the router, which can communicate with the network manager, is referred to as the near side, and the other side as the far side.

LonWorks Technology

LonWorks is a technology platform that consists of the tools, modules, and ICs required to build intelligent device and to install them in control networks. Each LonWorks device includes local processing and input/output (I/O) hardware to process input data from sensors, execute a control task, and control actuators. Each device also includes the capability to communicate with other devices using the LonTalk protocol in firmware.


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