Patent Publication Number: US-2002010801-A1

Title: Server to third party serial gateway in a power control management system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
     [0001] This application claims the benefit of U.S. Provisional Application No. 60/1 99,678 filed Apr. 21, 2000, which is hereby incorporated by reference in its entirety. 
    
    
     
       BACKGROUND OF INVENTION  
       [0002] This invention relates generally to computer systems and in particular, to a power control management system in which a plurality of power monitoring and control devices are coupled to and controlled by a computer through a common bus.  
       [0003] In known power control management systems, a control computer connected to an Ethernet or other network uses a network gateway to communicate with intelligent end devices (IEDs), such as relays, meters, and other analysis tools and power control devices. The network gateway facilitates communications between the computer and the network. IEDs usually are not Ethernet compatible devices, and typically use a known serial communications protocol. In order for the network control computer to communicate with one or multiple IEDs in a power control management system a gateway is required. A gateway is typically a programmable hardware device programmed to convert Ethernet or another communication protocol to a communication protocol recognized by the IEDs. In known systems, the gateways and servers were custom designed for use with only certain devices or IEDs. In such known power control management systems, a packet of programming information to be received or transmitted by the IED was encapsulated by a header, the information in the header being in the protocol of the computer network. At the gateway the header information is stripped away leaving a packet of information to be interpreted by the IEDs. Typically, parts of the header information and the gateway are proprietary products delivered as part of an entire system, and the gateway is not able to communicate with or support other devices even though those devices had the same hardware interfaces and communications protocols as the IEDs.  
       SUMMARY OF INVENTION  
       [0004] In one aspect, a power control management system is provided which includes an Ethernet server in a control computer and Ethernet gateways, which facilitate communications with intelligent end devices (IEDs). The server is configured to create and encapsulate messages intended for IEDs, in an industry standard format, and the Ethernet gateway is configured to communicate with the server.  
       [0005] In another aspect, a method is provided for communicating with intelligent end devices (IEDs) in a power control management system which includes at least one IED, an Ethernet gateway, and a control computer including an Ethernet server. The method includes electrically connecting the Ethernet gateway to the Ethernet server, configuring the server to create and encapsulate messages intended for IEDs in an industry standard format, configuring the gateway to remove the encapsulation from received messages for transmission to the IEDs, and transmitting the messages to the IEDs.  
       [0006] In yet another aspect, a computer is provided which is programmed to create and encapsulate messages in an industry standard format and further programmed to function as an Ethernet server for transmission of the messages.  
       [0007] In still another aspect, a gateway is provided which includes a programmable hardware device, configured to receive Ethernet messages from an Ethernet server in an industry standard format, remove both an Ethernet header and footer from the received Ethernet messages, leave messages intended for an intelligent end device and transmit messages to at least one intelligent end device. 
     
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
     [0008]FIG. 1 is a diagram of a known power control management system.  
     [0009]FIG. 2 is a diagram of a power control management system according to one embodiment of the present invention.  
     [0010]FIG. 3 is a TCP/IP Ethernet data packet in accordance with the invention. 
    
    
     DETAILED DESCRIPTION  
     [0011]FIG. 1 is a diagram of a known power control management system  10 . System  10  is divided into functional layers. A human interface layer  12  includes operating software that causes information to be formatted and presented to a user of the system, for example on a monitor. In the embodiment shown in FIG. 1, layer  12  includes a web interface  14 , a human machine interface (HMI)  16  for the power control management system, standard screens and wizards  18  to be used with HMI  16 , and a remote monitoring package  20 .  
     [0012] An application layer  30  includes software packages that further filter, refine and analyze data sent and retrieved from hardware comprising power control management system  10 . As an example, if a device in system  10  measures and analyzes a voltage waveform, a software package in application layer  30  compares a measured value of samples of the waveform against known upper and lower limit values as part of a test. Included in application layer  30  are windows applications  32 , an oscillography analysis and retriever module  36 , a sequence of events analysis and retriever module  40 , a data analyzer module  42 , and a reporting tool  44 . Oscillography analysis and retriever module  36  typically facilitates functions such as voltage waveform measurement and comparisons to known quantities.  
     [0013] Sequence of events analysis and retriever module  40  typically facilitates functions such as measurement and reporting of timing events, for example, frequency, or when a switch is turned off or on.  
     [0014] A dynamic data exchange (DDE)/object linking and embedding (OLE) for Process Control and operating system layer  50  includes control computer hardware  52  and associated servers. In a Power Management Host PC, such as system  10 , there are a number of commercially available proprietary protocol specific servers, for example Ethernet Server  54 , Modbus® Server  56 , MMS Server  58  and ION® Subsystem  60 . Modbus is a registered trademark of Gould Inc, located at 10 Gould Center, Rolling Meadows Ill. 60008, and ION is a registered trademark of Power Management LTD., located at 6703 Rajpur Place Victoria, British Columbia Canada. Dynamic data exchange and/or OLE for process control (OPC) allows external programs to access data in a windows environment through communications layer  70 . Modbus server  56  facilitates direct communication with a Modbus concentrator  72 , for communication with Modbus devices or other serial-communications based devices when a computer  52  is directly connected to a serial network. Further, Ethernet server  54  provides for Ethernet communication with a proprietary Ethernet gateway  74  typically located at or near IEDs to be controlled within system  10 . Control computer  52  and gateway  74  are electrically connected using an Ethernet medium (not shown). Server  54  and gateway  74  are, in known systems, proprietary products, custom designed for communication with a known set of intelligent end devices (IEDs). Typically, Ethernet server  54  and gateway  74  are supplied as one product of a manufacturer, and communications between the devices are accomplished using non-industry standard communications protocols. Therefore, to incorporate IEDs from multiple vendors into a system, such as system  10 , multiple proprietary Ethernet servers must be incorporated into the system.  
     [0015] The servers listed above service a plurality of communication interfaces as shown in communication interface layer  70 . Included in layer  70  are several gateways including a Modbus concentrator  72 , proprietary Ethernet gateway  74 , a Modbus monitor  76 , a utility communication architecture (UCA/MMS) and universal relay devices  78 , and a dial up modem  82 .  
     [0016] A meter and protection devices layer  100  shows a variety of devices available for communication within power control management system  10 . A variety of communications protocols are also shown. Using the Modbus concentrator  72 , multiple devices  102  communicate on a Modbus Network. Meters  104  and relay devices  106  communicate using proprietary Ethernet gateway  74 . Programmable logic controllers  108  and other legacy/third party applications  110  communicate directly with computer  52  either through a serial port attached to the computer or via the Ethernet.  
     [0017]FIG. 2 is a power control management system  200  according to one embodiment of the present invention. System  200  includes many of the same devices, packages and interfaces shown in system  10  of FIG. 1. Components in system  200  identical to components of system  10  are identified in FIG. 2 using the same reference numerals used in FIG. 1. System  200  includes an Ethernet server  210 , which provides communications within a network (not shown). Ethernet server  210  is configured for support of IEDs supplied by multiple third party vendors as described below. System  200  further includes an Ethernet gateway  220 , meters  104 , relays  106 , a third party protocol converter  222  that communicates with third party IEDs  224 , and other IEDs  226 . Ethernet gateway  220  controls and programs multiple devices, such as meters  104 , relays  106 , third party protocol converter  222 , and third party IEDs  224 . Other IEDs  226  include an Ethernet gateway and are directly controlled and programmed by Ethernet server  210 . IEDs  224  and  226  perform the hardware control functions of the power control management system, and in one embodiment includes on-board Ethernet gateways which also communicate with the power control management system Ethernet server. Third party IEDs  224  and other IEDs  226  are typically supplied by multiple third party vendors and have proprietary communications schemes.  
     [0018] Third party protocol converter  222 , third party IEDs  224  and other IEDs  226  that are directly supported through a third-party Ethernet gateway for addition into known power control management systems have heretofore been unavailable. Typically, Ethernet servers  54  (shown in FIG. 1) have been configured such that server  54  could only communicate through proprietary gateways, for example gateway  74  (shown in FIG. 1). Any attempt to communicate with a gateway such as Ethernet gateway  220  required a software driver and corresponding gateway which communicated in the same manner from the same vendor. Without additional software or protocol conversions means, server  210  supports communication with any serial based 3rd party gateway, and therefore IEDs, that directly embed the serial protocol in the data portion of the TCP/IP Ethernet packet. Thus, server  210  enables communications between serial-based IEDs and a power management control system (PMCS), for example system  200 , such that the IEDs can be connected to the PMCS without the need for proprietary software drivers and gateways.  
     [0019]FIG. 3 is a block diagram of a typical TCP/IP Ethernet communication protocol, including packeted device data  252 , a header  254 , and a footer  256 . Ethernet server  210  and gateway  220  (shown in FIG. 2) use TCP/IP communications protocol  250  when communicating with a computer network including network devices such as printers, scanners, programmable logic controllers, and other computers (not shown). Additionally, Ethernet server  210  and gateway  220  (both shown in FIG. 2) allow the computer network to communicate with other devices, such as meters  104 , relays  106  and third party IED&#39;s  226  (shown in FIG. 2), using other communication protocols. Server  210  encapsulates data  252  for a device, for example, a Modbus remote terminal unit, by packeting data  252  intended for the device within header  254  and, if necessary, a footer  256 . Thereafter, gateway  220  removes header  254  and footer  256  before sending data  252  to the devices.  
     [0020] Ethernet Server  210  is, in one embodiment, a software program running in layer  50  which creates and encapsulates Modbus messages intended for system IED&#39;s residing in layer  100 . Server  210  encapsulates Modbus messages  252  in an industry standard format with an industry standard TCP/IP Ethernet message header  254  and footer  256 . Server  210  encapsulates the Modbus messages  252 , with header  254  and footer  256  in order to transport Modbus message  252 , in the industry standard format, across an Ethernet network to Ethernet Gateway  220 . Ethernet Gateway  220 , upon receiving the message extracts Modbus message  252 , by extracting header  254  and footer  256 , from the data portion of the Ethernet message and transmits Modbus message  252  to the device. When an IED at layer  100  returns messages to the Ethernet Server  210 , Gateway  220  encapsulates the returned message with a header  254  and footer  256 , before passing the returned message to Ethernet server  210 .  
     [0021] Ethernet Server  210  further acts as a communication server to one or more software programs residing within layer  30 . Note that layer  50  also includes other communications servers (one for each type of support system protocol: Modbus, MMS, ION). As a communication server, Ethernet Server  210  acts as a conduit for all communication between the software programs within layer  30  and Ethernet Gateway  220  and eventually to the IEDs, for example, IEDs  226 . Ethernet Server  210  is electrically connected to Ethernet Gateway  220  via an Ethernet network. Ethernet Gateway  220  is further electrically connected to one or more IEDs  226  via an Ethernet network.  
     [0022] Ethernet server  210  and Ethernet gateway  220  allow industry standard programming protocols to be used when communicating with multiple IEDs  226 , supplied by multiple vendors, thereby allowing a user to take advantage of industry standardization in computer networking and connect the IED directly to the gateway without having concern whether the gateway and the PC-based server software have been specially designed and programmed to support the new device. Industry standardization provides additional benefits when a system user is adding additional IEDs to a system, which need to communicate with the system.  
     [0023] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.