Computer network adapted for industrial environments

• US 6,889,095 B1
• Filed: 06/11/1998
• Issued: 05/03/2005
• Est. Priority Date: 06/11/1998
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Eidson, John C., Sitte, Hans
• Primary Examiner(s): Backer, Firmin
• Application Number:
  US09/096,403
• Time in Patent Office: 2,518 Days
• Field of Search: 700/12, 395/296, 348/13, 348/7, 455/5.1, 710/5, 370/419, 370/431
• US Class Current: 700/12
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches

Abstract

A network for connecting a plurality of devices and the components used in constructing the network. The network includes at least one fan-out device for connecting the devices to each other. The fan-out device includes a controller, a top port and a plurality of downstream ports. The controller monitors messages received by the ports and generates messages that are sent via the ports. The network also includes a plurality of network cables, one per port. The network preferably utilizes a cabling system that includes twisted pairs for communicating the messages via the Ethernet protocol and power conductors for distributing power to the various network devices. The fan-out device includes one power component associated with each of the ports. Each power component provides connections between the power lines in the network capble and the ports of the fan-out device. The power components are used to power the devices on the network and to monitor the power lines for problems. Switching circuitry in the power components allows the fan-out device to isolate cable runs connected thereto that have shorts or other problems. The fan-out device preferably stores a device identification number that the controller transmits on all of the ports in response to a message received on one of the downstream ports. The controller also generates a signal on the top port that causes any device connected to the fan-out device via the top port to ignore the message. One embodiment of the fan-out device provides a hub that is transparent to Ethernet protocols while not introducing the jitter into the signals associated with the re-transmission and synchronization functions performed by conventional hubs.

Claims

1. A network for connecting a plurality of devices, said network comprising:

a fan-out device comprising a top port and a plurality of downstream ports, said fan-out device comprising;

a controller for monitoring messages received by said ports and for generating messages to be sent via said ports;

a first signal combining circuit for generating an upstream combined message comprising messages generated by said controller for said top port and messages received by said downstream ports, said upstream combined message being transmitted from said top port; and

a second signal combining circuit for generating a downstream combined message comprising messages generated by said controller for said downstream ports and messages received by said top port, said downstream combined message being transmitted from said downstream ports; and

a network cable connected to said top port and each of said downstream ports for communicating messages to and from said devices.

2. The network of claim 1 wherein said first signal combining circuit comprises a summing amplifier.

3. The network of claim 1 wherein said fan-out device conforms to the Ethernet standard for sending messages between said devices.

4. The network of claim 1 wherein said network cable comprises a twisted pair for communicating said messages.

5. The network of claim 1 wherein said network cable further comprises first and second power conductors.

6. The network of claim 5 wherein said fan-out device further comprises a plurality of power components, one such power component being associated with each of said ports, each power component being connected to said first and second power conductors of said network cable connected to said port associated with that power component, said fan-out device being powered by power received by one of said power components.

7. The network of claim 5 wherein said fan-out device is powered by said power component associated with said top port.

8. The network of claim 5 wherein each of said power components further comprises a circuit for detecting a predetermined condition on said first and second power conductors connected to said power component and for generating a signal indicative of the existence of said condition.

9. The network of claim 8 wherein each of said power components further comprises a switching circuit for disconnecting said first and second power conductors in said network cable connected to said port associated with said power component from said fan-out device.

10. The network of claim 8 wherein said controller generates and transmits a first error message indicating that said predetermined condition was detected, said message being sent via said top port.

11. The network of claim 5 wherein said network cable comprises first and second signal conductors and said fan-out device further comprises a plurality of signal line monitoring components, one such signal line monitoring component being associated with each of said ports, each signal line monitoring component being connected to said first and second signal conductors of said network cable connected to said port associated with that signal line monitoring component.

12. The network of claim 11 wherein each of said signal line monitoring components further comprises a circuit for detecting a predetermined condition on said first and second signal conductors connected to said signal line monitoring component and for generating a signal indicative of the existence of said condition.

13. The network of claim 12 wherein each of said signal line monitoring components further comprises a switching circuit for disconnecting said first and second signal conductors in said network cable connected to said port associated with said signal line monitoring component from said fan-out device.

14. The network of claim 12 wherein said controller generates and transmits a first error message indicating that said predetermined condition was detected, said message being sent via said top port.

15. The network of claim 1 wherein said fan-out device further comprises a circuit for storing a device identification number and wherein said controller generates and transmits an identification message containing said device identification number via said top and downstream ports, said controller further generating a signal on said top port that causes any device connected to said fan-out device via said top port to ignore said message.

16. The network of claim 15 wherein said identification message is generated in response to a request message received on one of said downstream ports.

17. The network of claim 16 wherein said identification message also includes information specifying which port on said fan-out device received said request message.

18. A fan-out device comprising a top port and a plurality of downstream ports, said fan-out device comprising:

a controller for monitoring messages received by said ports and for generating messages to be sent via said ports;

a first signal combining circuit for generating an upstream combined message comprising messages generated by said controller for said top port and messages received by said downstream ports, said upstream combined message being transmitted from said top port; and

a second signal combining circuit for generating a downstream combined message comprising messages generated by said controller for said downstream ports and messages received by said top port, said downstream combined message being transmitted from said downstream ports.

19. The fan-out device of claim 18 wherein said first signal combining circuit comprises a summing amplifier.

20. The fan-out device of claim 18 wherein said fan-out device conforms to the Ethernet standard for sending messages between devices connected to said ports.

21. The fan-out device of claim 18 wherein said fan-out device further comprises a plurality of power components, one such power component being associated with each of said ports, each power component being connected to first and second power terminals associated with that port, said fan-out device being powered by power received by one of said power components for connecting said power component to first and second power conductors.

22. The fan-out device of claim 21 wherein said fan-out device is powered by said power component associated with said top port.

23. The fan-out device of claim 21 wherein each of said power components further comprises a circuit for detecting a predetermined condition on said first and second power terminals connected to said power component and for generating a signal indicative of the existence of said condition.

24. The fan-out device of claim 23 wherein each of said power components further comprises a switching circuit for isolating said first and second power terminals.

25. The fan-out device of claim 23 wherein said controller generates and transmits a first error message indicating that said predetermined condition was detected, said message being sent via said top port.

26. The fan-out device of claim 18 wherein said fan-out device further comprises a plurality of signal line monitoring components, one such signal line monitoring component being associated with each of said ports, each signal line monitoring component having said first and second signal terminals for receiving messages on said port associated with that signal line monitoring component.

27. The fan-out device of claim 26 wherein each of said signal line monitoring components further comprises a circuit for detecting a predetermined condition on said first and second signal terminals and for generating a signal indicative of the existence of said condition.

28. The fan-out device of claim 27 wherein each of said signal line monitoring components further comprises a switching circuit for isolating said first and second signal terminals.

29. The fan-out device of claim 26 wherein said controller generates and transmits a second error message indicating that said predetermined condition was detected, said message being sent via said top port.

30. The fan-out device of claim 18 wherein said fan-out device further comprises a circuit for storing a device identification number and wherein said controller generates and transmits an identification message containing said device identification number via said top and downstream ports, said controller further generating a signal on said top port that causes any device connected to said fan-out device via said top port to ignore said message.

31. The fan-out device of claim 30 wherein said identification message is generated in response to a request message received on one of said downstream ports.

32. The fan-out device of claim 31 wherein said identification message also includes information specifying which port on said fan-out device received said request message.

33. A fan-out device comprising a top port and a plurality of downstream ports, said fan-out device comprising:

a plurality of summing circuits, one said summing circuit being associated with each of said ports; and

a plurality of signal receiving circuits, one of said signal receiving circuits being associated with each of said ports, wherein each of said summing circuits generates a signal comprising the sum of all of the signals received by said signal receiving circuits that are not associated with that port.

34. The fan-out device of claim 33 further comprising:

a controller for monitoring messages received by said ports and for generating a message to be sent via said ports, said generated message being sent by coupling said message to one of said summing circuits.

35. The fan-out device of claim 34 wherein said controller generates a collision message on all of said ports when said controller detects the simultaneous presence of two inbound messages to said fan-out device.

36. The fan-out device of claim 33 wherein said signal summing circuits comprise a summing amplifier.

37. The fan-out device of claim 34 wherein said fan-out device conforms to the Ethernet standard for sending messages generated by said controller.

38. The fan-out device of claim 34 wherein said fan-out device further comprises a plurality of power components, one such power component being associated with each of said ports, each power component being connected to first and second power terminals associated with that port, said fan-out device being powered by power received by one of said power components.

39. The fan-out device of claim 38 wherein said fan-out device is powered by said power component associated with said top port.

40. The fan-out device of claim 38 wherein each of said power components further comprises a circuit for detecting a predetermined condition on said first and second power terminals connected to said power component and for generating a signal indicative of the existence of said condition.

41. The fan-out device of claim 40 wherein each of said power components further comprises a switching circuit for isolating said first and second power terminals.

42. The fan-out device of claim 40 wherein said controller generates and transmits a first error message indicating that said predetermined condition was detected, said message being sent via said top port.

43. The fan-out device of claim 34 wherein said fan-out device further comprises a plurality of signal line monitoring components, one such signal line monitoring component being associated with each of said ports, each signal line monitoring component having said first and second signal terminals for receiving messages on said port associated with that signal line monitoring component.

44. The fan-out device of claim 43 wherein each of said signal line monitoring components further comprises a circuit for detecting a predetermined condition on said first and second signal terminals and for generating a signal indicative of the existence of said condition.

45. The fan-out device of claim 44 wherein each of said signal line monitoring components further comprises a switching circuit for isolating said first and second signal terminals.

46. The fan-out device of claim 44 wherein said controller generates and transmits a second error message indicating that said predetermined condition was detected, said message being sent via said top port.

47. The fan-out device of claim 34 wherein said fan-out device further comprises a circuit for storing a device identification number and wherein said controller generates and transmits an identification message containing said device identification number via said top and downstream ports, said controller further generating a signal on said top port that causes any device connected to said fan-out device via said top port to ignore said message.

48. The fan-out device of claim 47 wherein said identification message is generated in response to a request message received on one of said downstream ports.

49. The fan-out device of claim 48 wherein said identification message also includes information specifying which port on said fan-out device received said request message.