System and method for maintaining proper termination and error free communication in a network bus

• US 20040153870A1
• Filed: 10/20/2003
• Published: 08/05/2004
• Est. Priority Date: 04/26/2001
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Ellerbrock, Philip J, Konz, Daniel W.
• Granted Patent: US 7,581,031 B2
• Time in Patent Office: Days
• US Class Current: 714/47
• CPC Class Codes: G06F 13/4068 Electrical coupling
• CPC Class Codes: H04B 1/74 for increasing reliability, e.g. using redundant or spare channels or apparatus replacing by standby devices for amplifiers H03F1/52, H03F1/542
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 12/40032 Details regarding a bus interface enhancer
• CPC Class Codes: H04L 12/40045 Details regarding the feeding of energy to the node from the bus
• CPC Class Codes: H04L 12/40169 Flexible bus arrangements arrangements for maintenance or administration involving management of faults; events, alarms H04L41/06; automatic restoration of network faults H04L41/0654
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 2012/40267 Bus for use in transportation systems
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/0817 by checking functioning
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors
• CPC Class Codes: H04L 43/103 with adaptive polling, i.e. dynamically adapting the polling rate
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate
• CPC Class Codes: Y04S 40/00 Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them

Abstract

A system for maintaining proper termination and error-free communicaton in a network bus (12) including a power bus includes at least one network device (18), a network controller (16) and at least on bus protection element. The network devices (18) are electrically connected to and adapted to communicate via the network bus (12). The network controller (16), in turn, is electrically connected to the network bus (12) and is adapted to direct communicaitons with the network devices (18) via the network bus (12). The network controller (16) is also adapted to provide power signals to the network devices (18) via the power bus of the network bus (12). The network controller (16) and/or the bus protection elements can monitor signals on the network bus (12). And based upon the network controller (16) and/or bus protection elements identifying a predefined number of improper signals, the bus protection elements can selectively connect and disconnect respective network devices (18) to and from the network.

Claims

1. A system for maintaining proper termination and error-free communication in a network bus including a power bus comprising:

at least one network device electrically connected to and adapted to communicate via said network bus, wherein said at least one network device is capable of transmitting signals to said network bus, and capable of receiving signals from said network bus; and

a network controller electrically connected to said network bus, wherein said network controller is adapted to direct communications with said at least one network device via said network bus, and wherein said network controller is adapted to provide power signals to said at least one network device via the power bus of the network bus; and

at least one bus protection element disposed between said at least one network device and the network bus, wherein at least one of said at least one bus protection element and said network controller is capable of monitoring signals on the network bus to thereby identify improper signals on the network bus, and wherein the at least one bus protection element is capable of selectively connecting and disconnecting the at least one network device to and from the network bus based upon said at least one bus protection element and said network controller identifying a predefined number of improper signals on the network bus.

2. A system according to claim 1, wherein said at least one bus protection element is capable of monitoring the signals transmitted by said at least one network device and the signals received by said at least one network device, wherein said at least one bus protection element is capable of identifying improper signals transmitted by said at least one network device and controllably halting the transmission of signals from respective network devices onto the network bus if a predefined number of improper signals are identified.

3. A system according to claim 2, wherein each bus protection element comprises:

at least one isolation switch disposed between said at least one network device and the network bus, wherein said at least one isolation switch is capable of controllably halting the transmission of signals from said at least one network device onto the network bus; and

at least one logic element electrically connected to said at least one isolation switch and said at least one network device and capable of monitoring the signals transmitted by said at least one network device and the signals received by said at least one network device, wherein said at least one logic element is capable of identifying improper signals transmitted by said at least one network device and controllably operating said at least one isolation switch if a predefined number of improper transmitted signals are identified.

4. A system according to claim 2, wherein each network device includes a communications interface comprising:

a transmitter for transmitting signals from the network device to the network bus; and

a receiver for receiving signals on behalf of the network device from the network bus,

wherein said at least one bus protection element is capable of monitoring the signals transmitted by the transmitter and the signals received by the receiver.

5. A system according to claim 4 further comprising:

at least one diagnostic switch electrically connected to and disposed between the at least one transmitter and said at least one network device, wherein said at least one diagnostic switch is electrically connected to said at least one bus protection element, and wherein said at least one diagnostic switch is capable of controllably halting the transmission of signals from a respective network device to the respective transmitter,

wherein each bus protection element is capable of controllably operating a respective diagnostic switch if a predefined number of improper transmitted signals are identified, the transmitter and receiver associated with a respective network device are electrically connected such that after the bus protection element controllably operates the respective diagnostic switch to halt the transmission of signals from the respective network device the bus protection element is capable of transmitting diagnostic signals and receiving corresponding return signals, and wherein the bus protection element is capable of comparing the diagnostic signals and the return signals such that when the diagnostic signals and the return signals are substantially identical the bus protection element is capable of controllably operating the respective at least one isolation switch and the respective diagnostic switch to permit the transmission of signals from the respective network device.

6. A system according to claim 1, wherein each bus protection element comprises:

a first set of switches in-line with the network bus that are closed upon application of power to the power bus;

a second set of switches in-line with the network bus that are closed following the application of power to the power bus and in response to a command from said network controller; and

a termination element adapted to be switchably connected to the network bus upon the application of power to the power bus and to be switchably disconnected from the network bus in response to a command from said network controller.

7. A system according to claim 6, wherein bus protection element further comprises a first power detector for detecting the application of power to the power bus and, if power is applied to the power bus, for signaling said first set of switches to close and said termination element to be connected to the network bus.

8. A system according to claim 6, wherein each bus protection element transmits a response to said network controller once said first set of switches have been closed and said termination element has been switchably connected to the network bus.

9. A system according to claim 6 further comprising a second network controller, wherein said network controllers are connected to opposite ends of the network bus.

10. A system according to claim 6 wherein each network device is also associated with a network device interface connected to the network bus and connected to the network device via a data channel, said network device interface including said selective connection device.

11. A method for maintaining proper termination and error-free communication conducted via a network bus that is electrically connected to at least one network device, wherein the network bus includes a power bus, said method comprising:

monitoring signals on the network bus;

identifying a predefined number of improper signals from the signals on the network bus; and

switchably disconnecting the at least one network device after identifying a predefined number of improper signals.

12. A method according to claim 11, wherein monitoring comprises monitoring signals transmitted by the at least one network device to the network bus and the signals received by the at least one network device from the network bus, wherein identifying comprises identifying a predefined number of improper signals from the signals transmitted by the at least one network device to the network bus, and wherein switchably disconnecting comprises halting the transmission of signals from the at least one network device after identifying the predefined number of improper signals.

13. A method according to claim 12, wherein each network device includes a transmitter for transmitting signals from the network device to the network bus, and a receiver for receiving signals on behalf of the network device from the network bus, wherein each respective transmitter and receiver are electrically connected, said method further comprising:

transmitting diagnostic signals through the respective transmitter and thereafter receiving corresponding return signals from the respective receiver after halting the transmission of signals from the respective network device;

comparing the diagnostic signals and the return signals; and

permitting the transmission of signals from the respective network device to the network bus, wherein said permitting the transmission of signals comprises permitting the transmission of signals when the diagnostic signals and the return signals are substantially identical.

14. A method according to claim 11 further comprising:

detecting application of power signals to the power bus;

closing a first set of switches that are in-line with the network bus upon detecting the application of power to the power bus to thereby enable a first network device to communicate with a network controller via the network bus;

switchably connecting a termination element to the network bus upon detecting the application of power to the power bus to maintain the proper termination of the network bus;

closing a second set of switches that are also in-line with the network bus upon receipt of a command from a network controller via the network bus; and

switchably disconnecting the termination element from the network bus upon receipt of a command from the network controller via the network bus to enable the network controller to communicate with another network device,

wherein detecting, closing, switchably connecting, closing and switchably disconnecting all occur before monitoring signals on the network bus.

15. A method according to claim 14 further comprising closing a power switch that is in-line with the power bus upon receipt of the command from the network controller.

16. A method according to claim 14, wherein closing the second set of switches and switchably disconnecting the termination element from the network bus are in response to the same command from the network controller.

17. A method according to claim 14 further comprising transmitting a response to the network controller once the first set of switches is closed and the termination element is switchably connected to the network bus.

18. A method according to claim 14, wherein switchably connecting the termination element comprises switchably connecting the termination element to the network bus between the first and second sets of switches.

19. A method according to claim 14, wherein the network bus comprises the power bus and at least one pair of conductors, wherein switchably connecting the termination element comprises switchably connecting a respective termination element across each pair of conductors.

20. A bus protection element for operation with a network device electrically connected to and adapted to communicate via a bus, wherein the network device includes a communications interface having a transmitter for transmitting signals from the network device to the bus, and a receiver for receiving signals on behalf of the network device from the bus, said bus protection element comprising:

at least one isolation switch disposed between the communications interface and the bus, wherein said at least one isolation switch is capable of controllably halting the transmission of signals from the network device onto the bus; and

a logic element electrically connected to said at least one isolation switch and the communications interface and capable of monitoring the signals transmitted by the transmitter and the signals received by the receiver, wherein said logic element is capable of identifying improper signals transmitted by the transmitter and controllably operating said at least one isolation switch thereby halting the transmission of signals from the network device if a predefined number of improper transmitted signals are identified.

21. A bus protection element according to claim 20, wherein the predefined number of improper signals is dependant upon a predetermined number of signals transmitted by the transmitter, and wherein said logic element is capable of identifying the predetermined number of signals transmitted by the transmitter and controllably operating said at least one isolation switch thereby halting the transmission of signals from the network device if a predefined number of improper transmitted signals are identified.

22. A bus protection element according to claim 20 further comprising:

two diagnostic switch, wherein one diagnostic switch is disposed between the transmitter and the network device and the other diagnostic switch is disposed between the receiver and the network device, and wherein said diagnostic switches are capable of controllably halting the transmission of signals from the network device to the transmitter and the reception of signals by the network device from the receiver,

wherein said logic element is capable of controllably operating said diagnostic switches if a predefined number of improper transmitted signals are identified, wherein the transmitter and receiver are electrically connected such that after said logic element controllably operates said diagnostic switches to halt the transmission of signals from the network device and the reception of signals by the network device said logic element is capable of transmitting diagnostic signals through the transmitter and receiving corresponding return signals from the receiver, and wherein said logic element is capable of comparing the diagnostic signals and the return signals such that when the diagnostic signals and the return signals are substantially identical said logic element is capable of controllably operating said at least one isolation switch and said diagnostic switch to permit the transmission of signals from the network device to the bus via the transmitter.

23. A bus protection element according to claim 20, wherein said at least one isolation switch operates in at least one of an on mode wherein said at least one isolation switch permits the network device to transmit signals to the bus and an off mode wherein said at least one isolation switch prevents the network device from transmitting signals to the bus, and wherein said logic element is capable of controllably operating the mode of said at least one isolation switch.

24. A bus protection element according to claim 23, wherein said logic element is capable of operating said at least one isolation switch in the on mode before identifying the predefined number of improper signals, and wherein said logic element is capable of placing said at least one switch in the off mode after identifying the predefined number of improper signals.

25. A bus protection element according to claim 24 further comprising:

a diagnostic switch disposed between the transmitter and the network device, wherein said diagnostic switch operates in at least one of an on mode wherein said diagnostic switch permits the network device to transmit signals to the transmitter and an off mode wherein said at least one isolation switch prevents the network device from transmitting signals to the transmitter,

wherein said logic element is capable of controllably operating said diagnostic switch in the on mode before identifying the predefined number of improper signals, wherein said logic element is capable of placing said diagnostic switch in the off mode after identifying the predefined number of improper transmitted signals, wherein the transmitter and receiver are electrically connected such that after said logic element controllably places said diagnostic switch in the off mode said logic element is capable of transmitting diagnostic signals through the transmitter and receiving corresponding return signals from the receiver, and wherein said logic element is capable of comparing the diagnostic signals and the return signals such that when the diagnostic signals and the return signals are substantially identical said logic element is capable of placing said at least one isolation switch and said diagnostic switch in the on mode.

26. A bus protection element for maintaining proper termination and error-free communication in a network bus including a power bus, said bus protection element associated with at least one network device and adapted to selectively connect each associated network device to the network bus, said bus protection element also in communication with a network controller via the network bus, said bus protection element comprising:

a first set of switches in-line with the network bus that are closed upon application of power to the power bus;

a second set of switches in-line with the network bus that are closed following the application of power to the power bus and in response to a command from the network controller; and

a termination element adapted to be switchably connected to the network bus upon the application of power to the power bus and to be switchably disconnected from the network bus in response to a command from the network controller.

27. A bus protection element according to claim 26 further comprising a first power detector for detecting the application of power to the power bus and, if power is applied to the power bus, for signaling said first set of switches to close and said termination element to be connected to the network bus.

28. A bus protection element according to claim 27 further comprising a power switch in-line with the power bus that is closed in response to the command from the network controller.

29. A bus protection element according to claim 28 further comprising a second power detector including said power switch for detecting the application of power to the power bus and, if power is applied to the power bus, for signaling said second set of switches to close.

30. A bus protection element according to claim 26, wherein said second set of switches are closed and said termination element is disconnected from the network bus in response to the same command from the network controller.

31. A bus protection element according to claim 26, wherein said termination element is switchably connected to the network bus between said first and second sets of switches.

32. A bus protection element according to claim 26, wherein the network bus comprises the power bus and at least one pair of conductors, wherein the bus protection element comprises the same number of termination elements as the number of pairs of conductors, and wherein each termination element is adapted to be switchably connected across a respective pair of conductors.

33. A bus protection element according to claim 26, wherein said termination element comprises a resistor having a resistance that matches a characteristic impedance of the network bus.