Abstract:
A method and system for converting LonWorks® protocol in an electrical device management network to a different protocol for RF transmission between RF transceivers of the network and thereafter returning the converted protocol back to the LonWorks® protocol at a remote location without the need for software to make the conversions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application for Patent, Ser. No. 60/834,471, filed Jul. 31, 2006, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This application is generally directed to the field of LonWorks® seamless networking platforms used to monitor and control numerous computers, switches, electronic sensors, monitors and controllers for use with HVAC equipment, appliances, lighting, sprinkler and irrigation systems, power meters, valves, security systems, vending machines, office and industrial machinery, and the like used both in commercial buildings and private environments, wherein control logic is spread across an entire system or network without requiring separate controllers for separate devices or nodes of the network. More particularly, the invention is directed to the field of LonWorks® communication and control systems wherein the LonWorks® signals are converted to permit radio frequency (RF) transmissions in applications where hardwire connections are impractical or where communications must be made across extended ranges. 
     BRIEF DESCRIPTION OF THE RELATED ART 
     There is an ever growing movement to provide open communication systems that monitor, report, sense and control the functioning of electrical equipment such as HVAC equipment, irrigation system, lighting, appliances, switches, fans, valves, meters and the like over media including powerlines, optical fibers, twisted wires, coaxial cables, infrared (IR) and radio frequency (RF) transmissions. Such systems make it possible to optimize equipment operating parameters in order to maximize energy efficiencies in homes, apartments, hospitals, schools, places of business and in industrial and transportation industries. As opposed to prior art “master/slave” hierarchy communications between primary or central controllers and remote nodes or devices that are connected to the various monitors, switches, sensors and secondary controllers, in an open network, communication is open and peer-to-peer wherein each node or sets of nodes or devices may communicate with other nodes or sets of nodes using a common protocol, that is transmitted over any one of a plurality of different media. A universally recognized open network protocol to implement such communications was developed by Echelon® and is known as LonWorks®. The LonWorks® control networking platforms include a low bandwidth protocol known in the industry as ANSI/EIA709.1, EN14908, IEEE 1593-L and SEMI E56.6. The platforms include nodes or devices having dedicated Neuron® microprocessor chips that have been developed for control networking and which communicate by way of LonWorks® transceivers over various communication media including twisted pair wires, cables, powerlines, fiber optics and radio frequency (RF) with other nodes or devices of a network. Management of the networking platforms is by way of specially developed application software such that control and monitoring of the various nodes or devices may be done remotely, such as over Ethernet. 
     LonWorks® networks permit communication between as many as 32,000 devices or nodes, each of which is associated with equipment installed on a network including sensors, actuators, alarms and other warning devices, controllers, monitors and the like. Each node includes a 48 Bit identification. The devices or nodes are able to send and receive messages with respect to other devices or nodes on the network without knowing the topology of the network or the identity of the other devices or nodes of the network. The network management software interacts with the devices or nodes to set various identifications and protocol parameters, download specific applications or instructions, require reporting of specific information relating to the condition or operating characteristics of a piece of equipment, a switch, a sensor, a controller or the like, and to cause specific events to occur, such as turning a device ON or OFF, starting a process or machine, terminating power to stop a process or machine, or to change operating parameters such as the operating temperature of a buildings HVAC system by resetting a control thermostat. 
     For the network devices to communicate with the other devices or nodes of the network and the control or management software, the signals are processed through LonWorks® transceivers such as LonWorks® twisted pair and power line transceivers. One such transceiver is the FTT-10A transceiver that operates at 78 kbps baud rate over a range of about 500 meters. The range can be increase but requires the addition of repeaters. Although RF communication links have been established utilizing LonWorks® protocols, such links have been generally in-line or in-sight communications that require special management software such as Lonmaker® or Workplace Pro®. 
     In view of the foregoing, it would be a significant benefit to increase the range of RF communication of devices or nodes and management computers in a LonWorks® network without the need for additional management software so as to allow communication between a control site and one or more remotely positioned devices associated with equipment, switches, sensors or controllers located at distances beyond the currently effective ranges of current LonWorks® networks and wherein twisted wire or powerlines applications are not practical. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a bridging and RF modem system for permitting long distance RF communications within a LonWorks® network that includes two or more domains of nodes or devices that are remotely positioned relative to one another. Each device or node or sets of devices or nodes includes a Neuron® processor chip operating on a LonWorks® protocol and wherein the system includes a first set or domain of devices and/or controllers operating at one location that communicates through a first channel to a LonWorks® transceiver which outputs signal packets in the LonWorks® protocol to an input of a plug and play bridge device. The bridge device receives and stores the packets and converts or bundles the signals so as to be compatible for transmission over a serial transport line or device capable of transporting RS-232 signals. The packets that are bundled within the bridge are communicated to an RF transceiver where the signals are stored until the transceiver knows that communication is possible with one or more remote RF transceivers associated with domains or remote groups of controlled devices or nodes of the LonWorks® network. Once the signals are received by the remote RF transceivers they are communicated to another bridge device that converts the RS232 signals to the LonWorks® protocol and from which the signals are transported to LonWorks® transceivers and to the various devices or nodes of the remote domain. Signals from the controlled devices or nodes of the remote domain or domains are transported, converted, transmitted, converted and transported to the devices or nodes of other network domains in a reverse manner. The bridge devices may convert the signals to other communication media including but not limited to RS-422, RS-485 or Ethernet. 
     It is the primary object of the present invention to provide an RF system for communicating signals in an LonWorks® networking system wherein LonWorks® signal packets are converted for serial transport, such as RS-232 and related signals, prior to RF transmission, and are thereafter, after receipt at a receiving transceiver, reconverted to LonWorks® protocol for communication to devices or nodes within the LonWorks® network without requiring network management software and such that the range of RF transmission may be increased. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the invention will be had with reference to the accompanying drawings wherein: 
         FIG. 1  is a schematic flow chart showing the RF communication System for LonWorks® protocol networking in accordance with the present invention and including a management device that is connected directly to a LonWorks® twisted pair bus to give and receive information and to monitor the functionality of the controllers, sensors and monitors in a LonWorks® network; 
         FIG. 2  is a block diagram of one of the controllers, devices or nodes of the invention; and 
         FIG. 3  is a schematic chart showing a remote work station on an Ethernet setup for communicating with the devices and controllers on the LonWorks® busses of domains of a LonWorks® network. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the drawing figures, an RF communication System for LonWorks® protocol networking is disclosed. The network includes a first domain  10  including a plurality of sensing and/or control devices or nodes  12  that are associated with electronic devices, such as a switch A, a motor B, and a sensor C that are to be monitored and/or controlled using various software products that are downloaded within a management computer or processor  15 . By way of example, the control devices  12  may be Invensys MN20RS4 controllers. In the diagram of  FIG. 1 , the computer is a workstation that is located in the area of the first domain. It should be noted that the computer  15  may be located remotely from the network but must be operatively connected thereto by way of routers or other devices. 
     In  FIG. 2 , the nodes or devices  12  include a microprocessor chip  16 , such as a Neuron® chip, that includes a plurality of inline processors such that one or more processors may be used for executing the LonWorks® protocol so as to provide network communication and at least one processor that may be used for specific dedicated tasks that are unique to the controller associated therewith. Each chip may be customized and secured using layering techniques, however, the communication protocol remains compatible with the protocol of other processors of the network. In this manner, devices from separate vendors within the network can link with one another. 
     With continued reference to  FIG. 2 , the one or more microprocessors  16  are connected to transceivers  18 , such as the twisted wire and power line transceivers developed by Echelon®. In the preferred embodiment of the invention shown, the transceiver  18  is a FTT-10 transceiver operating at 78 kbps baud rate. The signal from the transceiver  18  is transmitted to a twisted wire, coaxial cable or power line bus  20  of the network, as shown in  FIG. 1 . It should be noted that the devices within the first domain are connected such that they may communicate directly with one another. As shown, controller  12 A communicates with the bus using a non-wire Wi-Fi link. 
     With further reference to  FIG. 1 , the network includes at least one second domain  10 ′ that is remotely spaced from the first domain by a distance that makes hardwire communication between the domains not practical using a LonWorks® protocol. The second domain also includes a plurality of sensing and/or control devices or nodes  12 ′ that are connected to electrical devices D, E, and F. The nodes include microprocessor chips connected to transceivers as previously described. The control devices  12 ′, the microprocessors and the transceiver are the same as those discussed with respect to the first domain. 
     In order to communicate the control devices or nodes  12  and  12 ′ of the first and second domains with one another such that information may be exchanged between the processors thereof, the information being communicated must be transmitted by a pair of RF transceivers  22  and  22 ′ associated with the first and second domains, respectively. By way of example, the transceivers may be Aerocomm CL4790-1000-232 transceivers. The transceivers may be selected from, but are not limited to, a variety of 900 MHz, 2.4 GHz, 5.8 GHz and 802.11 transceivers. The transceivers may employ the use of frequency hopping spread spectrum technology, data encryption, addressing and parameter adjustments as needed to increase performance and security. 
     Before signals in the LonWorks® protocol may be transmitted by the transceivers  22  and  22 ′, the signals must be converted from the LonWorks® protocol to a serial form such as RS-232, although the signals may be converted to RS-422, RS-485 and Ethernet media forms as well. To convert the form of protocol from LonWorks®, a bridge  25 , such as a DTI LonWorks® to serial bridge (D-LonbridgeRS), is connected at 23 to the twisted-pair bus receiving the LonWorks® signal from the controllers  12 . The bridge is a plug and play module which requires no setup or programming to perform the function of data transfer. The bridge provides transparent packetization and translation of Lonworks® data when the data is being passed from a LonWorks® twisted-pair bus to other media and from other media, using LonWorks® communication, to the LonWorks® twisted pair bus, respectively. The process of packet transmission is broken into two parts. First, the packets are received and then stored in the bridge&#39;s internal buffer before being sent to the RF transceiver  22 . The bridge bundles Lonworks® packets regardless of packet size. Once ready, the packets are forwarded by way of cable  24  to the RF transceiver  22  where they reside in another buffer until the RF transceiver sees that network communication is possible. The packets are segmented into a size not to exceed 80 bytes. Network readiness is defined as a period of time in which communications are silent from other LonWorks® nodes or devices on the network. Once transmitted over the RF link to remote RF transceivers  22 ′, the packets larger than 80 bytes in total length are reassembled by a remote bridge  25 ′, which is the same as bridge  25 . After reassembly, the packets are checked for errors and then forwarded in a reverse manner where they re-enter the native LonWorks® environment on a twist-pair bus  20 ′ of the second domain  10 ′. 
     It should be noted that more than one device, node or controller  12  or  12 ′ may be connected over the wire busses to the bridges  25  and  25 ′ and the additional domains may form part of the network. Communication from the remote devices  12 ′ to the devices  12  of domain  10  is in a reverse manner. 
       FIG. 3  shows a schematic diagram of a LonWorks® protocol system wherein a remote management computer  15 ′ is connected by way of the Ethernet  30  to two twisted-pair buses  20  and  20 ′ of two domains  35  and  36  of a LonWorks® network by way of routers  37  and  38  such that remote management of the controllers, devices or nodes  40  and  40 ′, similar to those discussed with respect to the embodiment shown in  FIGS. 1 and 2 , is possible. 
     The foregoing description of the present invention has been presented to illustrate the principles of the invention and not to limit the invention to the particular embodiments illustrated. It is intended that the scope of the invention be defined by all of the embodiments encompassed within the following claims and their equivalents.