Bridge for an industrial control system using data manipulation techniques

• US 20030051053A1
• Filed: 09/12/2001
• Published: 03/13/2003
• Est. Priority Date: 09/12/2001
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Vasko, David A., Lenner, Joseph A.
• Granted Patent: US 7,107,358 B2
• Time in Patent Office: Days
• US Class Current: 709/246
• CPC Class Codes: G05B 19/4185 characterised by the network communication
• CPC Class Codes: G05B 2219/31122 Bridge between networks
• CPC Class Codes: G05B 2219/31244 Safety, reconnect network automatically if broken
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A bridge usable in a highly reliable industrial control system provides an interface between a producer module transmitting redundant messages in accordance with a communication protocol and a consumer module receiving the messages in accordance with a different communication protocol. The bridge includes a first network interface receiving two messages from the producer, a microprocessor capable of converting the messages from the producer communication protocol to consumer communication protocol, and a second network interface transmitting the messages to the consumer. One of the messages is reversible altered with respect to the other message. The altered message is uninverted in the consumer module, and compared to the other message to ensure that no transmission errors have occurred.

Claims

1. A control system comprising:

(a) a first communication module transmitting data in accordance with a first communication protocol;

(b) a second communication module receiving data in accordance with a second communication protocol; and

(c) a bridge disposed between the first and second communication modules to provide an interface therebetween, the bridge including;

(i) a first network interface receiving a first and second redundant message from the first communication module, wherein the second message is encoded in a predetermined manner with respect to the first message;

(ii) a processor capable of converting the first and second messages from the first communication protocol to the second communication protocol if the first communication protocol differs from the second communication protocol; and

(iii) a second network interface transmitting the first and second converted messages to the second communication module.

2. The control system as recited in claim 1, wherein the second message is encoded with respect to the first message in the first communication module.

3. The control system as recited in claim 2, wherein the second message is decoded in the second communication module.

4. The control system as recited in claim 3, wherein the first message is compared to the decoded second message to determine whether a transmission error has occurred.

5. The control system as recited in claim 1, wherein the first and second communication protocol is selected from the group consisting of Ethernet, DeviceNet, ControlNet, Fire Wire and Field Bus.

6. The control system as recited in claim 1, wherein the first communication module is a producer of data.

7. The control system as recited in claim 6, wherein the second communication module is a consumer of data.

8. The control system as recited in claim 1, wherein the second message is inverted with respect to the first message.

9. The control system as recited in claim 1, wherein the data comprises I/O data.

10. The control system as recited in claim 1, wherein the data comprises peer to peer data.

11. The control system as recited in claim 1, wherein the first communication protocol is the same as the second communication protocol.

12. The control system as recited in claim 1, wherein the first communication protocol is different than the second communication protocol.

13. A bridge for interfacing a first communication module operating on a first communication protocol and a second communication module operating on a second communication protocol in a control system, the bridge comprising:

a first network interface receiving two messages from the first communication module in accordance with the first communication protocol, wherein one of the messages has been decoded in a predetermined manner with respect to the other message;

a processor receiving the messages from the first interface;

a second network interface receiving the messages from the processor and transmitting the messages to the second communication module, wherein the second communication module decodes the encoded message and compares the decoded message to the other message to determine whether a transmission error has occurred.

14. The bridge as recited in claim 13, wherein the first communication protocol is different than the second communication protocol, and wherein the processor converts the received messages from the first communication protocol to the second communication protocol.

15. The bridge as recited in claim 13, wherein the first and second communication protocol is selected from the group consisting of Ethernet, DeviceNet, ControlNet, Fire Wire and Field Bus.

16. The bridge as recited in claim 13, wherein the encoded message is inverted with respect to the other message.

17. A method of communicating between two modules of a control network operating on different network protocols, the steps comprising:

(A) transmitting two messages from a first communication module to a first network interface of a bridge operating a first communication protocol, wherein one of the messages has been encoded in a predetermined manner with respect to the other message;

(B) transmitting both messages from the first network interface to a microprocessor of the bridge;

(C) transmitting both messages from the microprocessor to a second network interface of the bridge operating on a second communication protocol; and

(D) transmitting both messages from the second network interface to a second communication module operating on the second communication protocol, wherein the second network interface decodes the encoded message and subsequently compares the messages to determine whether a transmission error has occurred.

18. The method as recited in claim 17, wherein the first communication protocol differs from the second communication protocol, and wherein the microprocessor converts the messages from the first communication protocol to the second communication protocol.

19. The method as recited in claim 17, wherein the first communication protocol is the same as the second communication protocol.

20. The method as recited in claim 17, wherein the encoded message is encoded with respect to the other message in the first communication module.

21. The method as recited in claim 17, wherein the first and second communication protocol is selected from the group consisting of Ethernet, DeviceNet, ControlNet, Fire Wire and Field Bus.

22. The method as recited in claim 17, wherein the first and second communication modules are selected from the group consisting of and input module, a controller module, an output module, and an actuator module.