U.S. patent application number 09/738433 was filed with the patent office on 2002-07-11 for web interface to a device and an electrical network control system.
Invention is credited to Baker, Richard A., Rolland, Jean-Marc.
Application Number | 20020091784 09/738433 |
Document ID | / |
Family ID | 39331671 |
Filed Date | 2002-07-11 |
United States Patent
Application |
20020091784 |
Kind Code |
A1 |
Baker, Richard A. ; et
al. |
July 11, 2002 |
Web interface to a device and an electrical network control
system
Abstract
A method and interface module for communicating messages with a
remote location and to provide access to an at least one
intelligent electronic device (IED) operably connected to a
communication network. The interface module is comprised of a
central processing unit and an operating system operating the
central processing unit. A network interface is operably connected
with the communication network. A protocol task processes
communication on the network according to a protocol stack. A set
of application tasks communicates with the protocol task for
responding to an incoming message from the communication network
and initiating an outgoing message to the communication network. An
interconnection bus with an interface driver is operably connected
with the at least one IED.
Inventors: |
Baker, Richard A.; (West
Newbury, MA) ; Rolland, Jean-Marc; (Le Versoud,
FR) |
Correspondence
Address: |
Larry I. Golden
Square D Company
1415 South Roselle Road
Palatine
IL
60067
US
|
Family ID: |
39331671 |
Appl. No.: |
09/738433 |
Filed: |
December 15, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09738433 |
Dec 15, 2000 |
|
|
|
09595159 |
Jun 15, 2000 |
|
|
|
09595159 |
Jun 15, 2000 |
|
|
|
08927005 |
Sep 10, 1997 |
|
|
|
Current U.S.
Class: |
709/208 |
Current CPC
Class: |
H04L 69/08 20130101;
H04L 41/08 20130101; H04L 69/161 20130101; G05B 2219/31104
20130101; G05B 2219/31422 20130101; Y04S 40/00 20130101; G05B
2219/31186 20130101; H04L 67/12 20130101; H04L 69/329 20130101;
H04L 67/02 20130101; H04L 69/16 20130101; H04L 69/169 20130101;
G05B 2219/34038 20130101; H04L 67/142 20130101; Y04S 40/18
20180501; H04L 67/025 20130101; H04L 9/40 20220501; H04L 41/0253
20130101; H04L 41/082 20130101; G05B 2219/32126 20130101; G05B
19/05 20130101; G05B 2219/31156 20130101; H04L 41/0803 20130101;
H04L 69/12 20130101; G05B 2219/15038 20130101 |
Class at
Publication: |
709/208 |
International
Class: |
G06F 015/16 |
Claims
We claim:
1. An interface module for communicating messages with a remote
location and to provide access to an at least one intelligent
electronic device (IED) operably connected to a communication
network, the interface module comprising: a central processing
unit; an operating system operating the central processing unit; a
network interface for communicating with the communication network;
a protocol stack for managing the communication on the network; a
protocol task for processing the communication according to the
protocol stack; a set of application tasks communicating with the
protocol task for responding to an incoming message from the
communication network and initiating an outgoing message to the
communication network; and, an interconnection bus with an
interface driver for communicating with the at least one IED.
2. The interface module of claim 1 wherein the communication
network is a worldwide Internet network using the Internet Protocol
(IP).
3. The interface module of claim 2 operating as a Web site on the
Internet, the interface module having a global IP address.
4. The interface module of claim 1 wherein the network interface is
operably connected to a driver.
5. The interface module of claim 4 wherein the network interface is
operably connected to an Ethernet driver.
6. The interface module of claim 4 wherein the network interface is
operably connected to a SLIP/PPP driver.
7. The interface module of claim 1 wherein the protocol stack is a
Transmission Control Protocol stack.
8. The interface module of claim 1 wherein the set of application
tasks includes a control task for processing the messages between a
remote location and the at least one IED using an industrial
communication standard Modbus over TCP/IP.
9. The interface module of claim 8 wherein the control task accepts
a connection; parses a Modbus message; and, calls the operating
system to process the Modbus message.
10. The interface module of claim 9 wherein the control task
comprises means for processing the Modbus message received from the
remote location over the communication network; accessing data on
the at least one IED; and, sending back a response.
11. The interface of claim 10 wherein the control task further
includes means for initiating the message allowing the at least one
IED to communicate with the remote module.
12. The interface of claim 1 wherein the set of application tasks
comprises a HTTP server task for processing the Hypertext Transport
Protocol (HTTP) to provide a standard Web access to a remote Web
browser.
13. The interface module of claim 12 wherein the HTTP server task
accepts a connection; parses an HTTP message; and, calls the
operating system to process the HTTP message.
14. The interface module of claim 13 wherein the HTTP message
allows a user at a remote location to view data within the at least
one IED from the browser operably connected to the communication
network.
15. The interface module of claim 13 wherein the HTTP message
allows a user at a remote location to write data within the at
least one IED from the browser operably connected to the
communication network.
16. The interface module of claim 2 wherein the set of application
tasks comprises a FTP server task for processing a File Transfer
Protocol (FTP).
17. The interface module of claim 16 wherein the FTP server task
accepts a connection; parses an FTP message; and, calls the
operating system to process the FTP message.
18. The interface module of claim 17 wherein the FTP message allows
a user at a remote location to download a file for updating the
operating software within the at least one IED through the
Internet.
19. The interface module of claim 17 wherein the FTP message allows
a user at a remote location to upload a file for obtaining data
records from the at least one IED through the Internet.
20. The interface module of claim 1 wherein the data transfer
enabling means comprises a dual TCP/IP stack.
21. The interface module of claim 20 wherein the dual TCP/IP stack
comprises a first stack capable of handling a broad range of TCP/IP
messages and a second stack capable of handling a less broad range
of TCP/IP messages more quickly than the first stack is capable of
handling the broad range of TCP/IP messages.
22. A control system for allowing a user access at a remote site
through a communication network, to information and data contained
in an electrical network control system having an at least one
intelligent electronic device (IED), the control system comprising:
means for coupling the remote site to the communication network,
the coupling means including a Web browser for interacting with the
communication network; a Web site associated with the electrical
network control system and accessible through the communication
network; means for linking the electrical network control system to
the Web site, the linking means including an interface module for
coupling the at least one IED to the communication network; means
for coupling the interface module to the at least one IED and
transferring messages between the interface module and the at least
one IED; means for enabling the message transfer between the remote
location and the electrical network control system; and, means for
processing a message received from the remote location over the
communication network, the means for processing the message
comprising means for receiving a message; means for accessing the
at least one IED for the message; and, means for sending a response
to the remote location through the communication network.
23. The control system of claim 22 wherein the communication
network is a worldwide Internet network using an Internet Protocol
(IP).
24. The control system of claim 22 wherein the interface module
operates as a Web site on the Internet, the interface module having
a global IP address.
25. The control system of claim 24 wherein the interface module
comprises a network driver for receiving the message from the Web
browser on the Internet and for sending a response back to the Web
browser.
26. The control system of claim 25 wherein the message transfer
enabling means comprises a protocol task using a Transmission
Control Protocol (TCP).
27. The control system of claim 26 wherein the protocol task
implements a dual TCP stack.
28. The control system of claim 27 wherein the dual TCP stack
comprises one stack capable of handling TCP/IP messages with a
higher priority than the other stack.
29. The control system of claim 28 wherein the message processing
means comprises a control task for processing a message exchange
over the communication network between a remote application and the
at least one IED using the industrial communication standard Modbus
over TCP/IP.
30. The control system of claim 29 wherein the control task accepts
a connection; parses a Modbus message; and, calls the operating
system to process the Modbus message.
31. The control system of claim 30 wherein the control task
includes means for processing the message received from the remote
location over the communication network; accessing data on the at
least one IED; and, sending back a response.
32. The control system of claim 31 wherein the control task further
includes means for initiating the message allowing the IED to
communicate with the remote location over the communication
network.
33. The control system of claim 28 wherein the data message
processing means includes a FTP server task for processing a File
Transfer Protocol (FTP).
34. The control system of claim 33 wherein the FTP server task
accepts a connection; parses an FTP message; and, calls the
operating system to process the FTP message.
35. The control system of claim 34 wherein the FTP message allows a
user at the remote location to download a file through the Internet
for updating the operating software within the at least one IED
associated with the electrical network control system.
36. The control system of claim 35 wherein the FTP message allows a
user at the remote location to upload through the Internet a file
for obtaining data records from the at least one IED associated
with the electrical network control system.
37. The control system of claim 28 wherein the data message
processing means includes a HTTP server task for processing a
Hypertext Transport Protocol (HTTP) to provide access to the remote
Web browser.
38. The control system of claim 37 wherein the HTTP task accepts a
connection; parses an HTTP message; and, calls the operating system
to process the HTTP message.
39. The control system of claim 38 wherein the HTTP message allows
a user at the remote location to view the electrical network
control system from a browser connected to the Internet.
40. The control system of claim 39 wherein the HTTP message allows
a user at the remote location to write to the electrical network
control system from a browser connected to the Internet.
41. The control system of claim 38 wherein the HTTP message allows
a user at the remote location to view IED data from a browser
connected to the Internet.
42. The control system of claim 39 wherein the HTTP message allows
a user at the remote location to write IED data from a browser
connected to the Internet.
43. The control system of claim 38 wherein a Java message allows a
user at the remote location to view IED data from a browser
connected to the Internet.
44. The control system of claim 39 wherein a Java message allows a
user at the remote location to write IED data from a browser
connected to the Internet.
45. The control system of claim 38 wherein an ActiveX message
allows a user at the remote location to view IED data from a
browser connected to the Internet.
46. The control system of claim 39 wherein an ActiveX message
allows a user at the remote location to write IED data from a
browser connected to the Internet.
47. A method of communicating with an intelligent electronic device
operably connected to a communication network, the method
comprising the steps of: utilizing a web browser to contact the
intelligent electronic device; and, obtaining information from the
intelligent electronic device.
48. The method of claim 47 further comprising the step of sending
information to the intelligent electronic device from the web
browser.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 09/595,159 filed on Jun. 15, 2000, entitled
"Web Interface To An Input/Output Device (SAA-35), which is a
continuation-in-part of U.S. patent application Ser. No.
08/927,005, filed on Sep. 10, 1997, entitled "Web Interface To A
Programmable Controller." This application is also related to the
following, commonly assigned applications entitled, "Messaging
Application Layer (MODBUS) Over Ethernet To Transport Layer (TCP)
Communications Method and Apparatus For A Modular Terminal
Input/Output System," U.S. patent application Ser. No. 09/166,870,
filed Oct. 6, 1998; "Web Interface To A Programmable Controller,"
U.S. patent application Ser. No. 09/303,458, filed Apr. 30, 1999;
"Interface To A Programmable Logic Controller," U.S. patent
application Ser. No. 09/223,349, filed Dec. 30, 1998; and
"Communications System For A Control System Over Ethernet And IP
Networks And Communication Interfaces For Such Systems," U.S.
Patent Application Ser. No. 60/078,223, filed Mar. 16, 1998. The
contents of these Applications are expressly incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates generally to the field of
protection, monitoring and controlling devices and modules for an
electrical network control system. More particularly, the present
invention relates to a system for coupling protection, monitoring
and controlling devices and modules to a Web server.
BACKGROUND OF THE INVENTION
[0003] Remote monitoring and control of Substation Automation
Systems (SAS), and protection, monitoring and controlling devices
has taken many forms. In the past, dedicated lines were the common
form of communication between a control system and a remote
location. This type of communication had limited application since
the control system was not accessible from multiple locations.
Modems have made it possible to access the control system from
different locations, but this type of access required implementing
generally specific communication protocols. Providing any type of
control function between locations is rather limited in this type
of environment. Furthermore, a customized interface is generally
required to access the control system by an end user.
[0004] With the growth of Internet and its World Wide Web providing
a delivery platform for organizing Internet data through hypertext
links, a client server system can be designed that will give each
end user the same type of user friendly interface and universal
access to services on the Web. The Web is a network of documents
called sites or pages stored on server computers throughout the
world. Each page typically contains text, multimedia offerings,
i.e., graphic images, video, or audio; and hypertext links to other
Web pages or documents. A browser allows a user to read and
interact with the Web page. The browser is a graphical software
program that sends commands to the Internet Web site and displays
whatever information is available on the page. As is well known,
various browser programs are commercially available from different
manufacturers.
[0005] The Internet network employs methods designed to handle many
general-purpose computers sharing a single cable, and therefore has
no ability to differentiate traffic in terms of its purpose or the
criticality of its data. The Internet is no longer a network of
computers sharing a single cable, but rather a web of
interconnected point to point links involving both general purpose
stations and specialized infrastructure components such as routers
and firewalls.
[0006] Most personal computers or work stations can be used by the
end user to connect to the Web through the commercially available
browsers. Communication over the Internet and other networks
requires one of several available protocols. Protocols such as
Internet Protocol (IP) provide for file transfers, electronic mail,
and other services. Commercially available programming languages
such as Java or ActiveX, along with Hypertext Markup Language
(HTML) and Extensive Markup Language (XML), are used in designing
layouts and graphics for a Web site or page and have extended
Internet technology such that a Web site can be used for dynamic
applications, e.g., applets or plug-ins, that can be downloaded and
run by the end user.
[0007] Many manufacturers provide automation information using
dedicated hardware and software with private communication
networking environments. Numerical protection units, electronic
meters, fault detectors, substation control units and Remote
Terminal Units (RTU) are widely used in control network systems. In
addition to these devices, monitoring and controlling modules for
smart power equipment (e.g. intelligent circuit breaker, switch
gear and power transformer) may also be integrated in process
control systems. Such specialized environments can be very
expensive. Furthermore, these systems are based on proprietary
communication busses and conversion products are required to allow
information carried over those networks to be visible on a
general-purpose network. There are significant installation and
other deployment costs associated with the existence of such
intermediate devices.
[0008] It would be desirable to develop an electrical network
control system whereby a user could use general purpose
communication networks, such as the Internet and specialized
industrial networks, directly connected to intelligent power
equipment, protection units, electronic meters, fault detectors,
substation control units and RTUs for remote monitoring and control
access.
[0009] This invention is designed to solve these and other
problems.
SUMMARY OF THE INVENTION
[0010] Accordingly, an object of the present invention is to
provide an interface between an electrical network control system
and a Web browser coupled to a communication network such as the
Internet.
[0011] Another object of the invention is directed to an interface
module for communicating messages with a remote location and to
provide access to an at least one intelligent electronic device
(IED) operably connected to a communication network. The interface
module is comprised of a central processing unit and an operating
system operating the central processing unit. A network interface
is operably connected with the communication network. A protocol
task processes communication on the network according to a protocol
stack. A set of application tasks communicates with the protocol
task for responding to an incoming message from the communication
network and initiating an outgoing message to the communication
network. An interconnection bus with an interface driver is
operably connected with the at least one IED.
[0012] A further object of the present invention is to provide
remote access through a Web browser to an Intelligent Electronic
Device (IED), i.e., intelligent power equipment, protection units,
electronic meters, fault detectors, substation control units, RTUs
and smart power equipment such as intelligent circuit breakers,
switch gears and power transformers.
[0013] The present invention allows for easy access over a
commercial network such as the Internet to information within at
least one IED. Access can be made locally or worldwide using a
commercial Web browser. The invention is comprised of a control
system of essential elements comprising a Web interface, a local
network, and a network interface to at least one IED.
[0014] The Web interface runs Web pages from an embedded interface
module coupled to the main IED processor board. The Web interface
module includes a network driver, a Transmission Control
Protocol/Internet Protocol (TCP/IP) stack, a hypertext transfer
protocol (HTTP) interpreter, a file transfer protocol (FTP) server,
and an interface driver to the IED.
[0015] The Web interface provides access to the IED by a user at a
remote location through the Internet. The interface translates the
TCP/IP, FTP and HTTP protocols used on the Internet into data
recognizable to the IED. Using this interface, the user can
retrieve all pertinent data regarding the operation of the IED and
the related process, i.e., configuration data; operating
statistics; diagnoses; and data from the process or the primary
equipment, such as input/output status, measurements, alarms, event
records, disturbance/fault records, power quality data and
predictive maintenance information.
[0016] The user can also modify parameters and send controls to the
IED. Updates to operating software can also be downloaded through
the Internet access and the FTP protocol. In the preferred
embodiment of the invention to a SAS, the IED is connected to an
Ethernet local network and the network driver is an Ethernet
driver.
[0017] Another object of the invention also allows for access to
smaller control systems such as pole-top control systems. For such
simple systems, the IED can be connected to regular telephone wires
using a phone modem wherein the network driver is a PPP
(Point-To-Point Protocol) or SLIP (Serial Line Internet Protocol)
driver.
[0018] Yet a further object of the invention is a method of
communicating with an intelligent electronic device operably
connected to a communication network. The method comprises the
steps of utilizing a web browser to contact the intelligent
electronic device. Information is obtained from the intelligent
electronic device using a protocol and programming language.
Information can also be sent to the intelligent electronic device
from the web browser. For instance, various protocols, i.e., HTML,
SGML, XML, etc. cooperate with known or yet to be developed
programming languages and technologies such as Java, ActiveX, etc.,
to communicate with the IED. The IED can also be controlled in this
manner from the web browser.
[0019] Other features and advantages of the invention, which are
believed to be novel and nonobvious, will be apparent from the
following specification taken in conjunction with the accompanying
drawings in which there is shown a preferred embodiment of the
invention. Reference is made to the claims for interpreting the
full scope of the invention which is not necessarily represented by
such embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an overview block diagram illustrating the
relationship between a user at a remote location and an Internet
Web site embedded in a control system and used for monitoring and
operating on an electrical network control system, according to the
present invention;
[0021] FIG. 2 is a block diagram illustrating the main features of
an embedded Web site associated with an intelligent electronic
device (IED), according to the present invention;
[0022] FIG. 3 is a block diagram of the present invention
illustrating an Internet interface to an IED;
[0023] FIG. 4 is a block diagram of the Web server module
illustrated in FIG. 2 according to the present invention; and,
[0024] FIG. 5 is a block diagram of the present invention
illustrating an IED operably connected to an SAS.
DETAILED DESCRIPTION
[0025] Although this invention is susceptible to embodiments of
many different forms, a preferred embodiment will be described and
illustrated in detail herein. The present disclosure exemplifies
the principles of the invention and is not to be considered a limit
to the broader aspects of the invention to the particular
embodiment as described.
[0026] FIG. 1 shows an overview block diagram illustrating the
relationship between a user 1 at a remote location and an Internet
Web site 3 embedded in a control system 7 used for monitoring and
operating a process.
[0027] The user 1 will have a personal computer (PC) 5 having a
commercially available browser 6, such as Netscape Communication's
Navigator or Microsoft's Internet Explorer, installed for viewing
the contents at the Web site through a communication network, such
as the Internet 4. The PC 5 provides a remote human-machine
interface (HMI) to the electrical network control system 7. Various
interconnection services are readily available to provide the
physical and electrical interconnection from the PC 5 to the
Internet 4 itself. The Internet 4 is a collection of independent
worldwide communication networks that are interconnected to each
other and function as a single connectionless entity. Communication
is based on a client-server basis, using a number of established
protocols that allow for communication and file transfers between
the client and the server. One of the most widely used protocols is
Internet Protocol (IP). The applications layer protocol interface
to the Web browser is typically through the HTTP protocol using the
HTML, XML, JAVA or ActiveX language. File transfers are typically
implemented through the FTP protocol.
[0028] The user 1 can connect to the Internet 4 using one of a
number of Internet service providers and will enter the address of
the Web site 3 when connected. The Web site 3 will display a home
page which may contain text, some type of multimedia offerings such
as graphic images, video, or audio, and possible hypertext links to
other Web sites or documents. Trouble shooting instructions,
maintenance logs, repair diagnostic information, quality control
parameters, etc., reside within the Web site 3 for convenient
access by the user. The browser 6 allows the user 1 to read and
interact with the page. The browser 6 will send commands to the Web
site 3 which will interact with an intelligent electronic device
(IED) 20 and display the information available from the electrical
network control system 7, concerning the process and the control
system itself. The browser 6 facilitates human interaction with the
electrical network control system 7.
[0029] FIG. 2 is a block diagram illustrating the main features of
an embedded Web site 3 associated with an IED 20. The Web site 3
includes a network interface 8 having a unique Internet address 9,
a server 10, and an IED interface 12. The server 10 includes a
hypertext transfer protocol (HTTP) interpreter and a FTP server and
uses a Transmission Control Protocol (TCP) in conjunction with
Internet Protocol through a Transmission Control Protocol/Internet
Protocol (TCP/IP) stack 11 to interact with the network interface
8. This enables the transfer of data and files between the IED 20
and the user 1 through the Internet 4. The IED interface 12
exchanges information with the IED 20 and enables the server 10 to
transfer/obtain data to/from the electrical network control system
7. The exchanged data can be used by the user at a remote location
to monitor and control the process. The transferred files can be
used (in a downloading direction) to update the operating software
on the IEDs 20 which the control system is based on and to get
measurements, events and disturbance/fault records (in an uploading
direction). The TCP/IP stack 11 enables data transfers over the
Internet 4 between the user 1 and the Web site 3 as required for
the various layers specified by the IP protocol.
[0030] FIG. 3 is a block diagram of the present invention
illustrating the Internet interface to an IED 20. The Web site 3
illustrated in FIGS. 1 and 2 is physically implemented on the Web
interface module 21. The Web interface module 21 includes the
network interface 8 having a unique Internet address 9 and a Web
server 22. The Web server 22 provides the home page for the Web
site 3. Security for the overall system can be included in the Web
server 22, but is generally maintained as part of the network
interface 8. A password and user list can be provided in initial
configuration files stored in the Web server 22 and can be
downloaded from a remote server. Protection of the configuration
file is provided by the remote server and the Web server 22 through
the password and the user list. By operably connecting the Web
server 22 with the IED 20 through the interconnection bus 24, the
Web server 22 provides a direct connection for the IED to the
Internet 4.
[0031] An IED 20 is any device having a communication input and/or
output capable of interfacing with the Web server 22 or other
devices. The IED 20 refers to devices such as sensors, actuators,
smart power equipment (e.g. intelligent circuit breakers, switch
gears and power transformers), protection units, electronic meters,
fault detectors, substation control units, RTUs and any other like
device as well as traditional I/O modules for PLC systems.
[0032] The Web server 22 provides both a client and a server
interface. All signals between the IED 20 and the Web server 22 are
through the interconnection bus 24. The interconnection signals
include addressing, control, data, and power. The client interface
allows the IED to send commands to a remote node over the Internet,
and the server interface allows for processing commands that
originate from the remote node. Substantially real time control of
the IED 20 from a remote HMI is possible by controlling the data
flow through the Web server 22.
[0033] The Web server 22 functions as a node on the communication
(TCP/IP) network 30 allowing it to send commands to the IED 20 and
receive the responses. Although the TCP/IP network 30 of the
preferred embodiment is an Ethernet network, other high level
protocols can be used. A user can control and view configuration
information and run-time data of the IED 20 through the Internet 4
by using a Web browser 6 at the remote location.
[0034] FIG. 4 is a block diagram illustrating the Web interface
module 21 in greater detail. The Web interface module 21 includes
various components to perform its functions: connection to the
TCP/IP network 30, connection to the IED 20, and application
functions (standard Web access, file transfer for software update
and records uploading, and monitoring and control access to the
IED).
[0035] Connection to the TCP/IP network 30 is through a network
driver 33. In the preferred embodiment of the present invention, to
a SAS, the IED 20 is operably connected to an Ethernet local
network and the network driver 33, is an Ethernet driver. FIG. 5
depicts the IED 20 operably connected to the SAS and the Internet
4. The connection to the Internet 4 is via an Ethernet connection
37. For a smaller control system such as a pole-top control system,
the IED 20 may be connected via a phone modem to regular telephone
wires. In this configuration, the Ethernet driver will be replaced
by a PPP (Point-To-Point Protocol) or SLIP (Serial Line Internet
Protocol) driver. The following description refers to the Ethernet
option. The connection to the TCP/IP network 30 is through an
Ethernet driver 33 and the connection to the IED 20 is through an
interface driver 38. Standard Web access is provided by a HTTP
server task 40. File transfer service is provided by a FTP server
task 41. And monitoring and control access to the IED 20 is
provided by a control task 42. Other possible protocols/interfaces
include placing the signal on electrical power lines.
[0036] A substantially real time operating system (RTOS) 32
controls the interaction between the components. The RTOS 32
allocates processor time on a central processor unit (CPU) 31 to
various tasks, provides memory management, and provides a set of
message services and signal services. The message and signal
services allow for communication between tasks, and between drivers
and a task. The RTOS can be a custom design or commercially
available, i.e., PSOS from ISI or VxWorks from Wind River
Systems.
[0037] Connection to the TCP/IP network 30 is through an Ethernet
driver 33 which transmits and receives messages at a rate of 10
Mb/s (megabits per second) or faster via an Ethernet controller 34.
It is contemplated that in the future, Ethernet controllers 34
capable of speeds of 1 Gb/s (gigabits per second) and faster can be
used. The physical connection over which communication is
facilitated can be over a fiber optic cable or a twisted pair-type
copper wire. Connection to the IED 20 is through an interface
driver 38 which transmits and receives data via a dual port memory
39 and an interconnection bus 24.
[0038] In addition to providing a standard interface to a remote
Web browser through the Internet 4, the interface module 21 also
enables the IED 20 to exchange control messages with other IEDs or
control units connected either on the local network 30, or on the
Internet network 4 at a remote location. This communication is
related to the control task 42 and will be processed using the
industrial standard Modbus over TCP/IP. The TC/IP stack 11 must
provide support for both broad range TCP/IP messages for the
Internet World and Modbus control messages. Alternatively, the
TCP/IP stack 11 can be replaced by a dual TCP/IP stack. The dual
TCP/IP stack comprises a first TCP/IP stack that provides support
for a broad range of TCP/IP messages (related to the HTTP task 40
and the FTP task 41). A second TCP/IP stack, a "smart stack,"
manages the high priority Modbus control messages (related to the
control task 42). For outgoing TCP/IP messages, the appropriate
TCP/IP stack is chosen by the calling HTTP, FTP or control tasks.
For incoming TCP/IP messages, the TCP/IP message is intercepted and
examined to determine its type. If the incoming message is a Modbus
control message, the message is then delivered to the "smart
stack." If the incoming message is not a Modbus control message,
the first TCP/IP stack handles the message. In this manner, Modbus
TCP/IP control messages are managed more quickly and efficiently
than a non-Modbus control message managed by the single TCP/IP
stack.
[0039] The Web interface module 21 has a unique global address 9
allowing it to be accessed by other devices on the network. The
Ethernet driver 33 manages transmit 36 and receive 37 buffers in
memory 35 and interfaces with the Ethernet controller 34. The
transmit 36 and receive 37 buffers are shared both by the Ethernet
controller 34 and the Ethernet driver 33. The Ethernet driver 33
also provides a transmit request interface and a receive indication
interface to the TCP/IP stack 11. The Ethernet controller 34
provides a transmit queue interface, a receive queue interface, and
generates interrupts on completion of transmitting a message and on
receiving a new message. The Ethernet driver 33 places receive
buffers in the receive queue. In the interrupt routine, the
Ethernet driver 33 examines the receive queue. If any messages are
in the receive queue, the Ethernet driver passes the receive buffer
to the TCP/IP stack 11. The TCP/IP stack 11 copies the buffer and
calls the Ethernet driver 33 to return the buffer and place the
returned buffer back into the receive queue.
[0040] The TCP/IP stack 11 calls the Ethernet driver 33 to transmit
a message. The Ethernet driver 33 allocates a buffer from the
shared memory 35, copies the message into the buffer, and places
the buffer into the Ethernet controller 34 transmit queue. In the
interrupt routine, the Ethernet driver 33 examines the transmit
queue, processes the transmission and frees the transmitted
buffers.
[0041] The TCP/IP network 30 enables the IED 20 to exchange control
messages with other IEDs or remote control units. In one direction,
the control task 42 allows a remote application to issue a request
command to the IED 20 and to receive its response. In the other
direction, the control task 42 allows the IED 20 to send data to a
remote application and to obtain responses.
[0042] The interface driver 38 provides a transmit request service
to the IED 20 and receives indication services from the IED. The
communication with the IED 20 is based on a dual port memory 39.
The dual port memory 39 allows a full-duplex and bi-directional
communication. The dual port memory 39 is split into two zones. One
zone is dedicated to the incoming side for communication from the
IED 20 and the other zone is dedicated to the outgoing side for
communication to the IED 20. Writing to a specified location will
cause an interrupt. For the incoming side, the IED 20 first writes
a message in the dual port memory 39 and then triggers an
interrupt. In the interrupt routine, the interface driver 38 reads
the memory to get the message from the IED 20. According to the
type of the message, the interface driver 39 uses a call back
routine mechanism to pass the message to either the HTTP task 40,
the FTP task 41 or the control task 42. For the outgoing side, the
HTTP task 40, the FTP task 41 or the control task 42 call the
interface driver 38 to transmit a message to the IED 20. The
interface driver 38 writes the message in the dual port memory 39
and then triggers an interrupt to the IED processor.
[0043] The control task 42 processes a message originating from a
control unit or another IED 20 at the remote location. The control
task 42 interfaces with the interface driver 38, the TCP/IP stack
11, and the RTOS message services. The control task 42 calls the
interface driver 38 and passes to it the message with a reference
to the associated call back routine for the response. The call back
routine uses the RTOS message services to send the response to the
control task 42. A TCP/IP stack 11 signal function also uses the
RTOS 32 IPC services to send a TCP/IP event to the control task 42.
The control task 42 can handle multiple transactions and
connections. The control task 42 maintains a list of connection
machines and each connection machine contains a list of transaction
machines. The connection machines manage the connection and the
transaction machines manage the incoming messages and
responses.
[0044] After performing an initialization, the control task 42
enters a loop and calls the RTOS 32 to receive a message. The RTOS
32 blocks the control task 42 until there is a message or there is
a time out. The control task 42 either receives a message from the
TCP/IP task's 11 signal handler from the interface driver 38 or it
times out. The control task 42 processes the message or the
time-out and reenters the loop. If the message received from the
RTOS 32 is from the TCP/IP task's 11 signal handler, the control
task 42 determines if the event is a connection request, a close
socket event or a receive data event. Based on the TCP/IP event,
the control task 42 uses the connection machine and transaction
machine to advance the transaction. Received data for a message may
occur over several receive data events and the transaction machine
assembles the events into a request message. When the response
message is received from the RTOS 32, the control task 42 locates
the connection and transaction machine to send the response.
[0045] When the control task 42 requests the TCP/IP stack 11 to
transmit a message, not all of the message may be transmitted. This
occurs when the remote node is flow controlled. In this case, the
associated connection is placed into a blocked state. Every time
the control task 42 calls the RTOS 32 to receive a message, it
searches the list of connection machines that are flowed
controlled. For each blocked connection, the control task 42 tries
to advance the transaction state machines.
[0046] After the control task 42 has parsed the header of an
incoming message, it attempts to allocate a structure to pass the
message to the interface driver 38. If the control task 42 is
already processing a predetermined number of outstanding messages,
the attempt fails and the connection is placed into a blocked
state. The body of the message is not read from the TCP/IP stack
11. As a result, the TCP/IP stack may apply flow control to the
remote node. When one of the other messages is complete, the free
data structure event causes a blocked connection machine to
continue processing the incoming message.
[0047] The FTP task 41 enables file transfers with the IED 20
through the communicating network 30. The FTP task 41 interfaces
with the TCP/IP stack 11 and the interface driver 38. The FTP task
41 receives a FTP request from the TCP/IP stack 11. To process the
request, the FTP task 41 may access the IED 20 through the
interface driver 38 and interconnection bus 24. The FTP task 42
sends back the response over the TCP/IP stack 11. A framework is
supplied by the RTOS 32. The framework creates the FTP task,
accepts connection, and parses the FTP request. After parsing the
request, the framework calls the RTOS 32 to process the request.
Processing the request involves determining the request type and
processing the actual request. A subset of FTP is implemented in
order to process file transfer operations. A download request
allows a user to update the operating software of the IED 20. An
upload request enables a user to get measurement, event and
disturbance/fault records provided by the IED 20. The processing of
TCP, FTP and HTTP stacks are well known in the industry.
[0048] The HTTP task 40 interfaces with the TCP/IP stack 11 and the
interface driver 38. The HTTP server task 40 receives a HTTP
request from the TCP/IP stack 11. To process the request, the HTTP
task 40 may access the IED 20 through the interface driver 38 and
interconnection bus 24. The HTTP server task 40 sends back the
response over the TCP/IP stack 11. The framework is supplied by the
RTOS 32. The framework creates the HTTP task, accepts connection,
and parses the HTTP request. After parsing the request, the
framework calls the RTOS 32 to process the request. Processing the
request involves determining the request type and processing the
actual request. The different request types allow a user to acquire
a snapshot of the IED 20 operations by allowing a view of various
data within the IED 20. These request types also include: display
of the IED 20 configuration; health statistics; readings;
interconnection bus configuration; Ethernet configuration and
statistics, and others. Images can be also displayed on the various
HTML pages by means of an image file, e.g., a "gif" file. Table 1
shows the various HTML pages the user can access to:
1 TABLE 1 Home Page/Login Readings Parameters Setup Quality
Information Monitoring and Diagnoses IED Configuration and
Statistics Ethernet Configuration and Statistics Security and
Administration
[0049] The Home Page contains hyperlinks to several pages of data.
This page will display the identification of the IED 20. A user
identification and password are required to access to the linked
pages.
[0050] The Readings page can display run time data about the
process, i.e.,
[0051] measurements: phase currents, voltages, tripping current,
frequency, real and reactive power, energy counters, temperature,
etc;
[0052] status: circuit breaker open/close positions, earthing
switch, protections enabled/disabled, recloser status, etc;
and,
[0053] events and alarms: alarm protection, tripping protection,
pole pressure, Buchholtz, etc.
[0054] The Parameters Setup page can display the current value of
the functions parameters, i.e., protection tripping curve,
threshold current, threshold voltage, tripping time delay, recloser
activation mode, etc. The IED 20 may have several sets of
parameters. This page enables the user to switch the active set to
another defined parameters set. Access to this page is protected by
a password.
[0055] The Quality information page can display voltage sag and
swell, harmonics and wave captures.
[0056] The Monitoring and Diagnoses page can display information
for network diagnosis and predictive maintenance, such as tripping
current, cumulative breaking current, breaker opening/closing time,
number of CB operations, disturbance records, etc.
[0057] The IED Configuration and Statistics page can display the
configuration of the IED 20 and give diagnostics information for
troubleshooting or performance analysis. In the case of a modular
IED 20, the first page provides access to a series of linked pages
related to the IED modules.
[0058] The Ethernet page can display information about the
configuration of the Ethernet Network Interface 8. Diagnostic
counters related to communication on the network can also
displayed.
[0059] The Security and Administration page can enable an
administrator to configure users' passwords and access rights,
i.e., no access, view only access, full access; to another
HTML.
[0060] The HTML pages provide a client/server user interface. This
interface is performed by requests and responses exchanged between
the browser 6 and the Web server 22. The RTOS 32 processes these
requests and responds by receiving and sending HTTP messages
through the TCP/IP stack 11. Processing some of these requests
involves reading and writing within the IED 20. To perform these
operations, the RTOS 32 sends a request to the interface driver 38
and uses an event signal mechanism and an event flag to determine
when the request is complete. After sending the request to the
interface driver 38, the RTOS 32 waits for an event flag to be
sent. When the interface driver 38 completes the request, it calls
a call back routine that sets the event flag. The RTOS 32 then
resumes processing the request.
[0061] While the specific embodiments have been illustrated and
described, numerous modifications are possible without departing
from the scope or spirit of the present invention.
* * * * *