Low cost redundant communications system

• US 6,133,846 A
• Filed: 10/01/1996
• Issued: 10/17/2000
• Est. Priority Date: 10/01/1996
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Birkedahl, Byron F., Eddy, Brett A.
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): Beaulieu, Yonel
• Application Number:
  US08/723,066
• Time in Patent Office: 1,477 Days
• Field of Search: 340/825.16, 340/825.5, 340/825.05, 340/825.02, 395/200.01, 395/200.02, 395/200.03, 370/431, 370/451, 370/458, 370/254
• US Class Current: 370/225
• CPC Class Codes: G05D 1/0077 using redundant signals or controls
• CPC Class Codes: G06F 11/2007 using redundant communication media
• CPC Class Codes: H04L 12/40 Bus networks
• CPC Class Codes: H04L 12/40013 Details regarding a bus controller
• CPC Class Codes: H04L 12/40189 by using a plurality of bus systems
• CPC Class Codes: H04L 12/407 with decentralised control
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04L 2012/4028 the transportation system being an aircraft
• 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

Abstract

A communications system capable of providing enhanced data integrity and reliability through redundant buses, and a network interface controller for use therewith. Redundant conductors conforming to well-known ethernet standards interconnect electronics components. Each component communicates with the conductors through a single network interface card (NIC). Each NIC comprises an ethernet compliant transceiver for each ethernet conductor in communication with the component. Microcontrollers embedded in each NIC synchronously and deterministically place data on the ethernet conductors according to a timing scheme stored in a non-volatile memory means. A heartbeat/power monitor is also provided to ensure that data cannot be transmitted in the event of a microcontroller failure. The communications system provides a high degree of redundancy and fault-tolerance and is therefore well-suited to critical applications in avionics communication.

Claims

1. A network interface controller connecting a component to a redundant communications bus having at least two data conductors, said network interface controller comprising:

at least three transceivers, each transceiver being in communication with at least one of said conductors;

a plurality of system network interface controllers (SNICs), each SNIC being in communication with at least one of said transceivers; and

a microcontroller in communication with each of said SNICs, said microcontroller being configured for sequencing data transmitted by said transceivers on said redundant communications bus.

2. The network interface controller of claim 1, wherein said microcontroller communicates with a non-volatile memory means having a lookup table, said lookup table corresponding to a timing sequence for transmitting data on said redundant communications bus.

3. The network interface controller of claim 1, wherein said transceivers are ethernet transceivers.

4. The network interface controller of claim 2, further comprising means for monitoring electrical power supplied to said microcontroller.

5. The network interface controller of claim 4, further comprising a watchdog means for monitoring the heartbeat of said microcontroller.

6. A redundant communications system for electronics components comprising:

a plurality of conductors including at least a left side bus, a right side bus, a left backup bus and a right backup bus; and

a plurality of network interface controllers, each network interface controller being in communication with one of said electronics components, said left side bus, said right side bus and either of said left backup bus or said right backup bus, and each network interface controller comprising;

a plurality of transceivers, each transceiver corresponding to one of said conductors;

a plurality of system network interface controllers (SNICs), each SNIC being in communication with at least one transceiver and said electronics component; and

a microcontroller coupled to said SNICs and sequencing data transmitted on said conductors.

7. The communications system of claim 6 wherein said conductors are ethernet conductors.

8. The communications system of claim 7 wherein said conductors are coaxial cables.

9. The communications system of claim 6 wherein said electronics components are avionics components.

10. The communications system of claim 9 wherein said microcontroller communicates with a non-volatile memory means having a lookup table, said lookup table corresponding to a timing sequence for transmitting said data on said redundant communications bus.

11. A communications system of claim 10 wherein said timing sequence is synchronous and deterministic.

12. A communications system of claim 11 further comprising means for verifying the presence of electric power and the heartbeat of said microcontroller.

13. A method of transmitting an electronic message between a first avionics component and a second avionics component, the method comprising the steps of:

receiving the electronic message from the first avionics component at a first system network interface controller (SNIC) and at a second SNIC;

monitoring a sequence of communications at a controller;

providing a signal from the controller to the first SNIC and to the second SNIC in response to the sequence of communications;

providing the electronic message from the first SNIC to a first transceiver and from the second SNIC to a second transceiver in response to the signal from the controller;

the first transceiver transmitting the electronic message on a first data bus that is in communication with the second avionics component; and

the second transceiver transmitting the electronic message on a second data bus that is in communication with the second avionics component.

14. The method of claim 13 further comprising the steps of:

providing the electronic message from the first SNIC to a third transceiver in response to the signal from the controller; and

the third transceiver transmitting the electronic message on a third database that is in communication with the second avionics component.

15. The method of claim 13 further comprising the steps of:

receiving the electronic message at a third SNIC;

providing the signal from the controller to the third SNIC in response to the sequence of communications;

providing the electronic message from the third SNIC to a third transceiver in response to the signal from the controller;

the third transceiver transmitting the electronic message on a third data bus that is in communication with the second avionics component.

16. The method of claim 15 wherein the first data bus, second data bus and third data bus are ethernet cables.

17. The method of claim 13 wherein the first data bus and the second data bus are coaxial cables.

18. The method of claim 13 wherein the first data bus and second data bus are ethernet cables.