December 2005

Innovations in Comfort, Efficiency, and Safety Solutions.

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Steve Nguyen, Director, Corporate Marketing, Echelon Corporation


EMAIL INTERVIEW  Steve Nguyen & Ken Sinclair

Steve Nguyen, Director, Corporate Marketing, Echelon Corporation


Pyxos™ Embedded Control Networks - Thinking Inside the Box™

The Pyxos platform is the world's first platform for embedded control networks – networks inside of machines.

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Reliable Controls

Sinclair:  What is an embedded control network?

Nguyen:  Embedded control networks extend networking to the discrete sensors (micro-switches, pushbuttons, shaft encoders, etc.), actuators (solenoids, pumps, valves, etc.), and displays (LCD, LED, etc.) embedded inside a machine or device. They represent a huge market that is not being addressed – that of networks inside of machines. Embedded Control Networks are at the bottom of the control networking pyramid if you will. At the top level are enterprise networks providing wide-scale control. At the middle level are local control networks that are addressed by the LONWORKS platform and include building automation systems, home automation, factory automation, street lighting, and so forth. Embedded control networks occupy the lowest layer and, until the creation of Pyxos, the market has lacked a well thought out, comprehensive control platform.

A true embedded control network should be both complimentary and synergistic with higher level control networks. For example, an air handling unit could operate by means of an embedded control network that makes the machine more reliable, easier and cheaper to manufacturer, have increased functionality, lower life-cycle costs, and be able to provide more diagnostic data. This same air handler should be installed and managed using the exact same software tools as the building automation system to which it belongs. In this scenario, a building integrator might not know that he had just added a complete embedded control network to his BAS.

Sinclair:  What is the Pyxos platform?

Nguyen:  The Pyxos platform is the world's first platform for embedded control networks – networks inside of machines. Pyxos networks are very low-cost, offer high speed deterministic operation, and are self-organizing into functioning systems without technically-skilled assembly personnel or laborious configuration tools or procedures. Pyxos processor ICs can be so small in size that they can fit into virtually any sensor or actuator. The platform is designed to be media independent for wired or wireless media, Pyxos networks receive and disseminate control information between sensors/actuators, displays, host processors and the other devices and components within a machine.

Self-organizing networks minimize assembly costs and time. Replacing troublesome wire harnesses with two-wire networks or, where appropriate, wireless networks, reduce assembly and warranty costs.

Pyxos Points are embedded inside sensors and actuators, manage network activity, and relay data to a Pyxos Pilot. The Pyxos Pilot then exchanges the control data with host processors, LONWORKS networks, to the Internet and beyond.

Sinclair:  How are Pyxos and LONWORKS networks different?

Nguyen:  Pyxos networks are intended to be embedded inside machines and connect the sensors/actuators that lay at the heart of those machines, hence the phrase, “Thinking Inside the Box™”. Pyxos networks operate at very high speeds over short distances making it an ideal platform for embedding control networks inside of machines and industrial applications. The Pyxos platform may also be used for small rooms and control applications, allowing installers or system integrators to reduce the cost of maintaining and installing devices that were not previously networked. For example, in a building system that has the VAVs on a LONWORKS BAS, the VAV controller could also be a Pyxos Pilot and the thermostats and motion sensors Pyxos Points. The benefits would include extending and leveraging the BAS, use of the standard LONWORKS installation tools for the VAV, self-installation (no software tool) of the Pyxos Points, free-topology wiring, power and data over the same wire, reduced parts, elimination of wiring errors, and greater reliability – a huge win for the end-user, installer, and equipment manufacturer.

LONWORKS networks interconnect machines and devices to one another and to the Internet.

Devices and machines on a LONWORKS network interoperate so that users can select products from different manufacturers for use in a single network. LONWORKS networks operate at a wide range of speeds and include a wide variety of Internet options including peer-to-peer tunneling and web services.

Reliable Controls Sinclair:  Can Pyxos and LONWORKS networks work together?

Nguyen:  Absolutely. A machine with a Pyxos embedded network can be seamlessly integrated with a LONWORKS network, using the LONWORKS network to connect to machines with a Pyxos embedded network, other machines or devices on a LONWORKS network, and the Internet.

Embedding a Pyxos network into the machines on a LONWORKS network creates a synergistic application - unlocking the rich set of data inside machines that can be used to further enhance the value and capabilities of control applications such as energy management and remote monitoring and maintenance; and improve the quality and profitability of such programs as service level agreements and facility management.

Pyxos Pilots bridge the two networks - behaving exactly like standard LONWORKS devices to allow manufacturers to take advantage of the growing worldwide market for LONWORKS control networks. A Pyxos machine with a LONWORKS interface can be integrated with a control application in the same manner as LONWORKS devices that do not use a Pyxos embedded network. They can be managed using standard LONWORKS network management tools, and interoperate with other LONWORKS devices. Furthermore, manufacturers of LONWORKS tools and integrators of LONWORKS networks can work with machines that incorporate Pyxos embedded control networks without additional training or re-engineering of their software.

Sinclair:  Does the Pyxos platform compete with wireless (RF) control networks like Zigbee?

Nguyen:  In certain market sub-segments, yes. The market for embedded control networks addressed by the Pyxos Platform is very broad and encompasses a wide range of applications that require twisted pair, power line, and other media and in many segments very price sensitive.

Pyxos is designed to be extremely reliable while still maintaining a low cost. RF based controls today, are unable to achieve high reliability at a reasonable cost level, let alone one that competes with Pyxos. Additionally, since the Pyxos platform is intended to be media independent, it can address a much wider range of control applications. In this sense the Pyxos platform is suitable for the entire market space for embedded control applications, whereas Zigbee, being exclusively RF, is limited to only a small subset of the overall market.

Zigbee, a proprietary control protocol that resides on top of the IEEE 802.15.4 open RF physical medium, is only able to address a very limited portion of the overall control market and is completely unsuitable for applications inside of a box, e.g., commercial washing machines, AHUs, etc. The Zigbee RF physical layer may be unsuitable for a wide range of applications (such as equipment housed in metal enclosures, buildings with metal foil wall paper or lathe, factory floors with movable metal partitions). Additionally, Zigbee, like other existing RF control schemes, is highly susceptible to noise generated from a variety of sources. The combination of these impediments means that Zigbee’s range of applications may be further limited.

More information about the state of wireless control today can be found at


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