METHOD AND APPARATUS FOR OPEN-WIRE FAULT DETECTION AND DIAGNOSIS IN A CONTROLLER AREA NETWORK

• US 20150346259A1
• Filed: 05/22/2015
• Published: 12/03/2015
• Est. Priority Date: 05/27/2014
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: JIANG, SHENGBING, DU, XINYU, WIENCKOWSKI, NATALIE ANN
• Granted Patent: US 9,568,533 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/54 Testing for continuity
• CPC Class Codes: G06F 11/0739 in a data processing system embedded in automotive or aircraft systems
• CPC Class Codes: G06F 11/0754 by exceeding limits
• CPC Class Codes: G06F 11/3013 where the computing system is an embedded system, i.e. a combination of hardware and software dedicated to perform a certain function in mobile devices, printers, automotive or aircraft systems testing or monitoring of control systems or parts thereof G05B23/02
• CPC Class Codes: G06F 11/349 for interfaces, buses
• CPC Class Codes: H04L 12/40006 Architecture of a communication node current supply arrangements H04L12/10; intermediate storage or scheduling H04L49/90
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN
• CPC Class Codes: H04L 43/0811 by checking connectivity

Abstract

A controller area network (CAN) includes a CAN bus with a CAN-H wire, a CAN-L wire, a pair of CAN bus terminators located at opposite ends of the CAN bus, each terminator having a corresponding known terminator resistance value, a plurality of nodes including controllers wherein at least one of said controllers is a monitoring controller. The monitoring controller includes a detection control routine for detecting the presence of a wire-open fault on the CAN bus, including determining a CAN bus resistance, and determining a wire-open fault on the CAN bus based upon the determined CAN bus resistance and the terminator resistance values.

Claims

1. A controller area network (CAN) comprising:

a CAN bus including a CAN-H wire and a CAN-L wire;

a pair of CAN bus terminators located at opposite ends of the CAN bus, each terminator having a corresponding known terminator resistance value;

a plurality of nodes including controllers wherein at least one of said controllers comprises a monitoring controller; and

said monitoring controller comprising a detection control routine for detecting the presence of a wire-open fault on the CAN bus, comprising the following steps;

determining a CAN bus resistance; and

determining a wire-open fault on the CAN bus based upon the determined CAN bus resistance and the terminator resistance values.

2. The controller area network (CAN) of claim 1, wherein the step of determining a CAN bus resistance comprises the following steps:

measuring a CAN bus voltage differential between the CAN-H wire and the CAN-L wire;

determining a CAN bus current; and

determining the CAN bus resistance based upon the CAN bus voltage differential and the CAN bus current.

3. The controller area network (CAN) of claim 2, wherein the step of determining a CAN bus current comprises the following steps:

measuring a voltage drop across a known resistance through which the CAN bus current passes; and

determining the CAN bus current based upon the voltage drop and the known resistance.

4. The controller area network (CAN) of claim 1, wherein the step of determining a wire-open fault on the CAN bus based upon the determined CAN bus resistance and the terminator resistance values comprises the following steps:

comparing the determined CAN bus resistance to a first resistance value equivalent to a parallel combination of the terminator resistance values;

comparing the determined CAN bus resistance to a second resistance value equivalent to one of the terminator resistance values; and

determining a wire-open fault on the CAN bus when the determined CAN bus resistance varies from the first resistance value by a first predetermined amount and the determined CAN bus resistance varies from the second resistance value by a second predetermined amount.

5. The controller area network (CAN) of claim 2, wherein the step of determining a wire-open fault on the CAN bus based upon the determined CAN bus resistance and the terminator resistance values comprises the following steps:

comparing the determined CAN bus resistance to a first resistance value equivalent to a parallel combination of the terminator resistance values;

comparing the determined CAN bus resistance to a second resistance value equivalent to one of the terminator resistance values; and

determining a wire-open fault on the CAN bus when the determined CAN bus resistance varies from the first resistance value by a first predetermined amount and the determined CAN bus resistance varies from the second resistance value by a second predetermined amount.

6. The controller area network (CAN) of claim 1:

wherein each CAN bus terminator comprises a split terminator including a pair of series coupled resistors coupled between the CAN-H and CAN-L wires and a capacitor coupled between a node between the resistors and a ground;

wherein said monitoring controller further comprises a diagnostic control routine for diagnosing a fault type of the wire-open fault on the CAN bus, comprising the following steps;

simultaneously measuring a CAN-H voltage and a CAN-L voltage; and

determining the fault type as one of a CAN-H wire open, CAN-L wire open and dual wire open based upon comparisons of summations of the CAN-H voltage and a CAN-L voltage.

7. The controller area network (CAN) of claim 1:

wherein each CAN bus terminator comprises a split terminator including a pair of series coupled resistors coupled between the CAN-H and CAN-L wires and a capacitor coupled between a node between the resistors and a ground; and

wherein said monitoring controller further comprises a diagnostic control routine for diagnosing a fault type of the wire-open fault on the CAN bus, comprising the following steps;

asynchronously measuring a CAN-H voltage and a CAN-L voltage; and

determining the fault type as one of a CAN-H wire open, CAN-L wire open and dual wire open based upon individual comparisons of the CAN-H voltage and a CAN-L voltage.

8. The controller area network (CAN) of claim 1:

wherein each CAN bus terminator comprises a standard terminator including a resistor coupled between the CAN-H and CAN-L wires; and

wherein said monitoring controller further comprises a diagnostic control routine for diagnosing a fault type of the wire-open fault on the CAN bus, comprising the following steps;

measuring a CAN-H voltage and a CAN-L voltage; and

determining the fault type as one of a CAN-H wire open, CAN-L wire open and dual wire open based upon comparisons of summations of the CAN-H voltage and a CAN-L voltage.

9. A controller area network (CAN) including a plurality of CAN elements comprising a communication bus and a plurality of controllers, comprising:

a two-wire communications bus including first and second terminators, each terminator comprising a known termination resistance electrically connected between first and second wires of the communications bus;

a plurality of controllers signally connected to the communications bus;

a monitoring controller signally connected to a first of the wires of the communications bus via a first shunt resistor and signally connected to a second of the wires of the communications bus via a second shunt resistor, the first and second shunt resistors being equal in resistance;

said monitoring controller monitoring a first voltage (V_S) across the second shunt resistor, monitoring a second voltage (V_CAN) between the first and second wires of the communications bus, monitoring a third voltage (V_H) between the second wire of the communications bus and an electrical ground, and monitoring a fourth voltage (V_L) between the first wire of the communications bus and the ground, said monitoring controller calculating a resistance of the communications bus based upon the first and second voltages and the resistance of the second shunt resistor;

said monitoring controller detecting presence of a wire-open fault in the two-wire communications bus when the calculated resistance of the communications bus equals the known termination resistance of the terminators; and

said monitoring controller diagnosing one of a wire-open fault in the first wire, a wire-open fault in the second wire, and a wire-open fault in both the first and second wires based upon V_H and V_L.

10. The controller area network (CAN) of claim 9 wherein each terminator comprises a split terminator including a pair of series coupled resistors coupled between the first wire of the communications bus and the second wire of the communications bus, and a capacitor coupled between a node between the series coupled resistors and the ground.

11. The controller area network (CAN) of claim 9 wherein each terminator comprises a standard terminator including a resistor coupled between the first wire of the communications bus and the second wire of the communications bus.

12. A controller area network (CAN) comprising:

a CAN bus including a CAN-H wire and a CAN-L wire;

a pair of CAN bus terminators located at opposite ends of the CAN bus, each terminator having a corresponding known terminator resistance value;

a plurality of nodes including controllers wherein at least one of said controllers comprises a monitoring controller; and

said monitoring controller comprising a detection control routine for detecting the presence of a wire-open fault on the CAN bus, comprising the following steps;

determining a CAN bus resistance;

comparing the determined CAN bus resistance to a first resistance value equivalent to a parallel combination of the terminator resistance values;

comparing the determined CAN bus resistance to a second resistance value equivalent to one of the terminator resistance values; and

determining a wire-open fault on the CAN bus when the determined CAN bus resistance varies from the first resistance value by a first predetermined amount and the determined CAN bus resistance varies from the second resistance value by a second predetermined amount.

13. The controller area network (CAN) of claim 12:

wherein each CAN bus terminator comprises a split terminator including a pair of series coupled resistors coupled between the CAN-H and CAN-L wires and a capacitor coupled between a node between the resistors and a ground; and

wherein said monitoring controller further comprises a diagnostic control routine for diagnosing a fault type of the wire-open fault on the CAN bus, comprising the following steps;

simultaneously measuring a CAN-H voltage and a CAN-L voltage; and

determining the fault type as one of a CAN-H wire open, CAN-L wire open and dual wire open based upon comparisons of summations of the CAN-H voltage and a CAN-L voltage.

14. The controller area network (CAN) of claim 12:

wherein each CAN bus terminator comprises a split terminator including a pair of series coupled resistors coupled between the CAN-H and CAN-L wires and a capacitor coupled between a node between the resistors and a ground;

wherein said monitoring controller further comprises a diagnostic control routine for diagnosing a fault type of the wire-open fault on the CAN bus, comprising the following steps;

asynchronously measuring a CAN-H voltage and a CAN-L voltage; and

determining the fault type as one of a CAN-H wire open, CAN-L wire open and dual wire open based upon individual comparisons of the CAN-H voltage and a CAN-L voltage.

15. The controller area network (CAN) of claim 12:

wherein each CAN bus terminator comprises a standard terminator including a resistor coupled between the CAN-H and CAN-L wires; and

wherein said monitoring controller further comprises a diagnostic control routine for diagnosing a fault type of the wire-open fault on the CAN bus, comprising the following steps;

measuring a CAN-H voltage and a CAN-L voltage; and

determining the fault type as one of a CAN-H wire open, CAN-L wire open and dual wire open based upon comparisons of summations of the CAN-H voltage and a CAN-L voltage.