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iLon, Brings the Web to LonWorksBy Michael Foley
utilities. The days of control networks that are islands unto themselves are over. The pervasiveness of the Internet is mandating that every network provide some type of path or gateway to the central or enterprise LAN. With the advent of information appliances, LonWorks is attempting to break free of its isolation with gateways and enter into the Internet generation. Echelon's iLon 1000 Internet Server is a device that bridges data from a Lonworks network to the Internet for monitoring and control through standard Web browsers.
Let's take a quick look at control networks and LonWorks. A simple definition for a control network is: any group of devices working in a peer-to-peer fashion to monitor sensors, control actuators, communicate reliably, manage network operation, and provide complete access to network data. Control networks provide deterministic timing of commands, responses, events, and data transfers. LonWorks is based upon the LonWorks protocol, also known as the EIA 709.1 Control Networking Standard. Neuron chipsets are used in transceivers for communicating across LonWorks. LonWorks consist of devices such as:
All interactions and events are setup through the LNS network operating system. LNS provides configuration, diagnostics, and maintenance for LonWorks networks. LNS automates common system tasks, handles directory management, and routes services. LNS is configured through the LonMaker development tool. LonMaker is a software package for designing, installing, operating, and maintaining LonWorks networks. Based on LNS, LonMaker is a graphical programming tool that uses Microsoft Visio to release developers from the constraints of having to write code to design a LonWorks distributed control network.
iLon provides Web pages to view LonWorks devices and control them. It is built solidly for harsh environments and can act as a:
iLon's key features include:
The LonWorks router application establishes a virtual LonWorks channel over IP, which is referred to as a LonWorks/IP channel. Data is tunneled across the LonWorks/IP channel. Configuration Server is used to setup on PC systems to establish LonWorks/IP channels and maintain a database of the channels. Channels can contain up to 40 devices.
The FTP server is used to build the directory structure on the iLon and to transfer files. The iLon has approximately 1 MB of storage space available for storage of user files. Application files are transferred to the iLon via FTP. Simple Network Time Protocol (SNTP) is used to synchronize the iLon with time servers. These servers can be located within a LAN or on the Internet. SNTP server settings are set through Configuration Server. iLon serves data through its Web services. The Web server supports standard Web pages generated with HTML and can incorporate dynamic data updates through Web page refresh or through Java scripting.
The iLon's CPU is a RISC processor with a MIPS 3900 core running at 50MHz. It runs on Wind River's VxWorks embedded operating system. It has 16 MB of RAM and 4 MB of flash storage. Up to 1 MB of flash memory is dedicated for user files such as Web pages, images, and data files. During operation, iLon can be placed on a shelf or rack-mounted using brackets that screw into the server.
Network connectivity is provided through its 10Mbps 10BaseT RJ45 port. Network setup is done through a DB9 RS232 serial console port using terminal emulator software, such as hyperterminal, running on a host PC. iLon contains a LonWorks interface based on the Neuron chipset and communicates to LonWorks through a two-wire interface (TP/FT-10 or TP/XF-1250 connector). iLon is a headless system, but does provide LEDs to indicate system and communication status.
Installation is rather straightforward. The software for building projects and drivers for the PC host and LonWorks interface card is loaded first. The LonWorks interface card is then installed into the PC host system. Upon start up the hardware is detected and initialized. A LonWorks network card utility is placed in the control panel to check communications.
Configuring the iLon for operation consists of three steps:
LonMaker is integrated within Visio to leverage its graphical capabilities to setup LonWorks. Visio comes with the LonMaker Integration Tool and is installed during the installation process. There are special stencils within Visio for LonWorks components such as iLon. Each LonPoint module and iLon adheres to the LonMark guidelines, so information about the devices in external interface files is uploaded directly from the devices onto LonMaker. The LonMaker page resembles a schematic that shows device connections and interactions. The bottom of the layout displays the devices connected to the channel. The top shows device interconnects and flow. The drawing below shows an example of a LonWorks design using LonMaker. Since it is graphical by nature, it plainly shows the layout of the network. If it looks pretty easy, that's because it is.
iLon's extended HTML tags provide access to system and network variable data. The <iLonWeb> is the tag used within Web pages to signal the server to include dynamic data. This tag is only recognized by iLon servers and will cause errors in browsers if it is served by other Internet servers. The <iLonWeb> tag is used to:
The tag syntax is:
The following Web page was built using HTML with <iLonWeb> tags and Java scripts. It uses the <iLonWeb> tag to place dynamic data into the page.
The documentation only discusses sending data through Web pages using HTML and Java script to render within the browser, but the iLon can do much more. The data can be formatted for XML, ASCII text, or other types of output. XML data from the iLon can be requested by other network servers for enterprise level data aggregation. The following code formats the data within XML when the page is requested:
<?xml version="1.0" encoding="UTF-8"?>
It also can formatted for raw data output for use in Java applets or ActiveX controls:
Current_Temp = <ILONWEB func=ShowValue symbol=NVL_nviTempSensor></ILONWEB>
On the other hand, it can only operate with LonWorks and can only collect data from LonWorks devices. There is minimal security functionality on the system, mainly username and password authentication, since SSL and data encryption usually put a heavy burden on these type of low-end appliance servers. It also lacks email client functionality for event or alarm notification. One last drawback is that it's missing a data push option that schedules data transfers to other servers at set intervals. This function is mainly used for aggregating data from multiple systems.
Looking forward, Ethernet is extending itself into controlled environments with its high speed, wide adoption, dropping cost points, and Ethernet switches that provide deterministic functionality. This will limit the adoption of LonWorks and the iLon. But, if you're using or planning to use LonWorks, iLon provides an option for bridging data onto the Web.
Check out iLon's home networking demo at: http://demo.echelon.com.
Pricing and Availability
The iLon 1000 Internet Server Starter Kit is currently available for $2,995. |
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