Communication control system

• US 4,864,568 A
• Filed: 10/14/1987
• Issued: 09/05/1989
• Est. Priority Date: 10/16/1986
• Status: Expired due to Fees

• Current Assignee: Nippondenso Company Limited 1-1 Showa-Cho Kariya-Shi Aichi Japan, Toyota Jidosha Kabushiki Kaisha 1 Toyota-Cho Toyota-Shi Aichi-Ken Japan
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Saito, Takao, Sato, Yoshihisa, Akiyama, Susumu, Ito, Katsunori, Hirabayashi, Yuji
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Evans, Geoffrey S.
• Application Number:
  US07/109,170
• Time in Patent Office: 692 Days
• Field of Search: 371/8, 371/22, 371/9, 371/10, 371/11, 370/16, 370/85, 340/825.01, 379/16, 364/200, 364/900, 364/424.01, 364/424.02, 364/424.03, 364/424.05, 364/425, 375/40
• US Class Current: 714/4.1
• CPC Class Codes: B60R 16/0315 using multiplexing techniques multiplexing for transmission of signals G08C15/00; multiplexing for electrical communication in general H04J
• CPC Class Codes: G06F 11/2007 using redundant communication media
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability

Abstract

Control units are mutually connected by separate common signal lines. A data link is provided between the control units via a preselected one of the common signal lines. A check is made as to whether the preselected common signal line is operating normally or abnormally. When the preselected common signal line is operating abnormally, the preselected common signal line is replaced by another common signal line in the data link.

Claims

1. A communication control system for a vehicle comprising:

(a) a plurality of separate units mounted on the vehicle;

(b) first and second separate lines connected to each of the separate units, thereby connecting the units;

(c) means for providing communication between the units via the first line, wherein said communication causes at least one change of a potential at the first line during a first predetermined interval when the first line is in a normal state of operation;

(d) means for detecting a malfunction of the first line, said detecting means comprising means for determining the occurrence of at least one change of a potential at a portion of the first line during a second predetermined interval, said second predetermined interval being longer than the first predetermined interval; and

(e) means for providing communication between the units via the second line when a malfunction of the first line is detected

2. The system of claim 1 wherein said detecting means comprises a monostable multivibrator, said monostable multivibrator determining said second predetermined interval.

3. A communication control system comprising:

(a) a plurality of control units;

(b) a plurality of separate common signal lines connected to each of the control units, thereby connecting the control units;

(c) means for providing a data link between the control units via a preselected one of the plurality of common signal lines, and for outputting transmission data to the preselected line during every first predetermined interval;

(d) means for detecting a change of a potential on the preselected line;

(e) means for determining a malfunction on the preselected line and outputting a malfunction signal in response thereto when a change of the potential at the portion of the preselected line remains undetected for a second predetermined interval, the second predetermined interval being longer than the first predetermined interval, said determining and outputting means being disposed within a first of said plurality of control units;

(f) a malfunction signal line connected to each of said plurality of control units, said malfunction signal line transmitting said malfunction signal from said first of said plurality of control units to another of the control units; and

(g) means for replacing the preselected line with another of the common signal lines in response to said malfunction signal.

4. The system of claim 3 wherein said data link provides token bus communication between the control units.

5. The system of claim 3 wherein said determining means comprises a monostable multivibrator for determining the second predetermined interval.

6. The system of claim 3 wherein the replacing means simultaneously inhibits the data link on the preselected line and enables the data link on the another of the common signal lines in response to the malfunction signal.

7. A communication control system comprising:

(a) first and second units;

(b) first and second separate data signal lines connecting the control units;

(c) means for transmitting data from the first unit to the second unit via the first data signal line;

(d) means disposed in the second unit for detecting a malfunction of the first data signal line and generating a malfunction signal representative thereof, said malfunction detecting means generating said malfunction signal when said malfunction detecting means does not detect a predetermined change in potential on said first data signal line within a predetermined interval;

(e)malfunction signal line connecting the first and second units and being separate from the first and second data signal lines;

(f) means for transmitting the malfunction signal from the second unit to the first unit via the malfunction signal line;

(g) switching means, disposed in the first unit, for selecting the second data signal line in place of the first signal line in response to the malfunction signal, said switching means disabling said first data signal line at the same time said second data second line is selected;

(h) means for transmitting data from the first unit to the second unit via the second data signal line.

8. The system of claim 7 wherein said malfunction detecting means comprises a monostable multivibrator for determining the predetermined interval.