Dual protocol stack for maximum speed access to a programmable logic controller (PLC) in a factor automation system

• US 6,963,922 B2
• Filed: 04/14/2003
• Issued: 11/08/2005
• Est. Priority Date: 09/10/1997
• Status: Expired due to Term

• Current Assignee: Schneider Automation Incorporated (Schneider Electric SE)
• Original Assignee: Schneider Automation Incorporated (Schneider Electric SE)
• Inventors: Tanzman, Allan, Naismith, Ronald H., Papadopoulos, A. Dean
• Primary Examiner(s): Prieto, Beatriz
• Application Number:
  US10/414,662
• Publication Number:
  US 20030195975A1
• Time in Patent Office: 939 Days
• Field of Search: 709/203, 709/217, 709/218, 709/219, 709/223, 709/224, 709/230
• US Class Current: 709/230
• CPC Class Codes: G05B 19/05 Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
• CPC Class Codes: G05B 19/054 Input/output
• CPC Class Codes: G05B 2219/1208 Communication, exchange of control, I-O data between different plc,
• CPC Class Codes: G05B 2219/15038 Internet, tcp-ip, web server see under S05B219-40
• CPC Class Codes: G05B 2219/31104 Remote configuration of parameters of controlled devices
• CPC Class Codes: G05B 2219/31124 Interface between communication network and process control, store, exchange data
• CPC Class Codes: G05B 2219/31156 Network structure, internet
• CPC Class Codes: G05B 2219/31186 TCP-IP internet protocol
• CPC Class Codes: G05B 2219/31422 Upload, download programs, parameters from, to station to, from server
• CPC Class Codes: G05B 2219/32126 Hyperlink, access to program modules and to hardware modules in www, web server, browser
• CPC Class Codes: G05B 2219/34038 Web, http, ftp, internet, intranet server
• CPC Class Codes: H04L 41/0803 Configuration setting
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/025 for remote control or remote monitoring of applications
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/142 Managing session states for stateless protocols; Signalling session states; State transitions; Keeping-state mechanisms
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/169 : Special adaptations of TCP, UDP or IP for interworking of IP based networks with other networks protocols for interworking, protocol conversion H04L69/08
• CPC Class Codes: H04L 69/329 : in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 : Network security protocols

Abstract

A control system includes an Internet web interface to a network of at least one programmable logic control system running an application program for controlling output devices in response to status of input devices. The Web interface runs Web pages from an Ethernet board coupled directly to the PLC back plane and includes an HTTP protocol interpreter, a PLC back plane driver, a TCP/IP stack, and an Ethernet board kernel. The Web interface provides access to the PLC back plane by a user at a remote location through the Internet. The interface translates the industry standard Ethernet, TCP/IP and HTTP protocols used on the Internet into data recognizable to the PLC. Using this interface, the user can retrieve all pertinent data regarding the operation of the programmable logic controller system.

Claims

1. An interface module in a factory automation system for receiving messages from a remote location, the interface module providing access to a control system of the factory automation system including a programmable logic controller having at least one operably connected I/O module, the interface module comprising:

a central processing unit;

a real time operating system operating the central processing unit;

a network interface for facilitating communication with the control system of the factory automation system;

a back plane driver for communicating with the programmable logic controller through a back plane of the programmable logic controller; and

;

a dual protocol stack including a first and second protocol stack, the interface module being capable of parsing through received messages and distributing messages involving control aspects between the controller and the at least one I/O module to the second protocol stack wherein execution of messages residing on the second protocol stack are expedited with respect to messages residing on the first protocol stack.

2. The interface module of claim 1 wherein the control system being operably connected to a world-wide network utilizing an Internet Protocol (IPF).

3. The interface module of claim 2 wherein the interface module functions as a web site on the world-wide network, the interface module including a global IPF address.

4. The interface module of claim 2 wherein the interface module allows a user at a remote location to view data within the programmable logic controller from a browser operably connected to the world-wide network.

5. The interface module of claim 1 wherein the network interface is an Ethernet Driver.

6. The interface module of claim 1 wherein the dual protocol stack is a Transmission Control Protocol stack.

7. The interface module of claim 1 wherein the dual protocol task includes a server task using a hypertext transport protocol (HTTP) to driver hypertext documents to the network interface.

8. The interface module of claim 7 wherein the HTTP task accepts a connection, parses an HTTP request, and calls the real time operating system to process the request.

9. The interface module of claim 1 wherein the second protocol stack is implemented when source protocol is the Internet Assigned Number of 502 and the destination port is above a port number 3072.

10. The interface module of claim 1 further comprising:

a client task for communicating with the back plane driver and the protocol stack for initiating received requests;

a server task for communicating with the back plane driver and the protocol stack for responding to received requests; and

a protocol task for communicating with the back plane driver and the protocol stack for receiving and responding to protocol task requests.

11. For an interface module being capable for receiving messages from a remote location and providing access to a control system including a programmable logic controller having at least one operably connected I/O module, the interface module further including a dual protocol stack including a first protocol stack and a second protocol stack, a method of facilitating control communication with the control system comprising the steps of:

receiving a message;

determining whether the received message includes a control aspect; and

,

distributing the received message with the control aspect to the second protocol stack wherein execution of messages residing on the second protocol stack are expedited with respect to messages residing on the first protocol stack.

12. An interface module for receiving messages from a remote location, the interface module providing access to a control system including a programmable logic controller having at least one operably connected I/O module, the interface module comprising:

a central processing unit;

a real time operating system operating the central processing unit;

a network interface for facilitating communication with the control system;

a back plane driver for communicating with the programmable logic controller through a back plane of the programmable logic controller; and

;

a dual protocol stack including a first and second protocol stack, the interface module being capable of parsing through received messages and distributing messages involving control aspects between the controller and the at least one I/O module to the second protocol stack wherein execution of messages residing on the second protocol stack are expedited with respect to messages residing on the first protocol stack, wherein the dual protocol stack comprises a dual TCP/IP stack.

13. An interface module for receiving messages from a remote location, the interface module providing access to a control system including a programmable logic controller having at least one operably connected I/O module, the interface module comprising:

a central processing unit;

a real time operating system operating the central processing unit;

a network interface for facilitating communication with the control system;

a back plane driver for communicating with the programmable logic controller through a back plane of the programmable logic controller; and

;

a dual protocol stack including a first and second protocol stack, the interface module being capable of parsing through received messages and distributing message involving control aspects between the controller and the at least one I/O module to the second protocol stack wherein execution of messages residing on the second protocol stack are expedited with respect to messages residing on the first protocol stack, wherein the first protocol stack comprises a first TCP/IP stack and the second protocol stack comprises a second TCP/IP stack.

14. An interface module as defined in claim 13, wherein the second protocol stack is optimized to handle a predefined set of TCP/IP messages.

15. An interface module as defined in claim 14, wherein the predefined set of TCP/IP messages is associated with the programmable logic controller.