INTERFACE UNIT FOR DIAGNOSTIC COMMUNICATION, FOR A SELF-ADAPTABLE BRAKING SYSTEM Background of the Invention 1. - Field of the Invention This invention relates to a fault display and interface unit for an electronic vehicle control system, such as a self-adaptive braking system. 2.- Description of the Previous Technique. Electronic vehicle control systems, such as self-adaptive braking systems, usually work quite well and are very reliable. However, due to the environmental and physical stresses to which the components of these systems are subjected due to being mounted in the adverse environment outside the vehicle, these systems occasionally fail. Many of these failures are rather simple to correct. For example, a common fault is a short or open detector or a modulator failure, which can be caused by a broken wire, a connector that is loosened by vibration, etc. These faults are relatively simple, even for a relatively untrained mechanic to correct them. In addition, some faults are intermittent. Since the warning device is activated only during the fault, the warning device is not activated until the failure occurs again. According to this, there is not an easily accessible record of this failure, so even if the vehicle was given service in the meantime, the defect probably would not have been noticed or corrected. The U.S. Patent No. 4,837,552 describes a unit wherein a series of light-emitting diodes
(LEDs = Light Emitting Diodes) are provided in the housing within which the electronic control unit component of the system is mounted. The description of the U.S. Patent. No. 4,837,552 is incorporated herein by reference. In the unit described in the patent, each of the light emitting diodes is activated in response to a predetermined discrete system failure. For example, one of the light emitting diodes may be activated in response to a fault in one of the wheel speed detectors, and another of the light emitting diodes may be activated in response to a fault in one of the modulators. According to this, a mechanic with relatively little dexterity is able to examine the wires, connectors, etc. associated with the corresponding wheel speed detector modulator. If a broken wire is found or a loose connector is discovered, the mechanic can quickly repair the system, probably in the field, thereby saving valuable time that would ordinarily be required to send the vehicle to a maintenance site to perform diagnostic tasks more sophisticated. Of course, if the mechanic is not successful in locating this simple fault, or if the light emitting diode corresponds to a fault for example in the logic controller of the system is activated, the driver knows immediately that the vehicle must be taken to a site of maintenance where a skilled mechanic in repairing electronic systems is available. Faults detected by the system and indicated towards the light emitting diodes are stored in a non-volatile memory when the system is de-energized. Once a failure occurs, the fault is stored in the memory, and the corresponding indicator when the system is turned on at a later time. According to this, if an intermittent or transitory failure occurs, the mechanic prepares the system immediately will know that this failure has occurred at some time during the operation of the vehicle. However, diagnostic LEDs have proven to be difficult to observe when installed in a dark location on the vehicle's frame rail or tank. COMPENDIUM OF THE INVENTION The present invention relates to a diagnostic communication interface unit (the DCI Diagnostic Communication Interface) that contains LEDs for diagnostic display and a rest function similar to those contained in the anti-interlocking ECUs described above and also contains a computer serial port connection to be used in conjunction with a personal computer (PC = Personal Computer). the DCI communicates with integrated anti-interlocking ECU on a serial communication duct through the J1587 diagnostic connector of the vehicle that is located in the vehicle cab. The DCI is an electronic diagnostic tool that can be used to interpret the fault diagnosis in the anti-interlocking braking system. the DCI can be used either as a stand-alone diagnostic tool or with Acom software from the AlliedSignal Truck Brake Systems company that is compatible with Microsoft Windows software. DCI can also be used in conjunction with other diagnostic software. When used by itself, the DCI is able to locate faults in individual anti-interlock systems using the series of LEDs or lamps that indicate that the faulty device is a wiring and the location in the vehicle. the DCI has twelve lamps and the reset switch. A row of 10 lamps is similar to the diagnostic LED display that is found in some prior art anti-interlock controllers. The other two lamps indicate that the DCI has a power or power source and that the communication link with the ECU is established. When used in conjunction with a personal computer that has compatible diagnostic software installed, such as the Acom software from AlliedSignal Truck Brake Systems, the DCI becomes a communications arbitrator among the numerous on-board controllers of the vehicle and the personal computer. In this mode, all tests and diagnostics are performed by the personal computer and the Acom software of the AlliedSignal Truck Brake Systems company or other compatible diagnostic software. the DCI can be used both independently and with a PC, making the unit ideal for solving simple and more detailed problems of the anti-interlock braking system (ABS = Antilock Brake System) and automatic traction control (ATC = Automatic Traction Control) . The described system is also easily expanded and updated by changes in PC software. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference is made to exemplary preferred embodiments of the inventions shown in the accompanying drawings, wherein:
Figure 1 is a diagrammatic illustration of a truck anti-interlock diagnostic system utilizing a communication interface unit for diagnosis in accordance with the present invention; Figure 2 is a front view of a DCI according to the present invention; Figure 3 is a side view of the ICD shown in Figure 2; Figure 4 is an end view of the connector to the DCI as illustrated in Figure 2; Figure 5 is a block diagram showing the functional relationship of the DCI components; and Figure 6 is a detailed electrical schematic of the ICD. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Now with reference to the drawings and to Figure 1 in particular, a truck anti-interlock diagnostic system 10 is illustrated, utilizing a diagnostic communication interface unit 12 in accordance with the present invention. . An electronic control unit anti-interlock (ECU = Electronic Control Unit) 14 is mounted integrally in the chassis of the truck, where ABS and ATC are used. The ECU 14 communicates with the DCI 12 on a serial duct 16. The serial duct 16 has a vehicle diagnostic connector J1587 to which a cable 20 of the DCI is connected. the DCI 12 includes a computer serial port connector 13 to connect to a PC 18. The DCI has 12 LEDs. Ten of the LEDs provide diagnostic verification of the ABS / ATC and the other two LEDs are used to indicate that the DCI has a power source and that a communication link is established. The ECU 14 comprising a part of the larger electronic diagnostic system 10, is housed within an enclosure that is mounted on the chassis of the truck. The ECU 14 also includes ports for connection to vehicle speed detectors and self-adaptive braking pressure modulators. Speed detectors are usually wheel speed detectors that are mounted on the wheels of the vehicle. These detectors are conventional and provide a pulsed output that is transmitted to the ECU 14, the frequency of the pulses is to provide it at the speed of the wheel. The ECU 14 processes the signals that are received from the speed detectors and generates output signals that control one or more brake pressure modulators. Brake pressure modulators are known in the art and are also conventional. The brake pressure modulators are adapted to decrease and subsequently increase the braking pressure in response to the imminent wheel interlocking conditions detected by the ECU 14 in response to the signals generated by the speed detectors. The ECU 14 also includes diagnostics that verify the ECU 14, the modulators, wheel speed detectors, components for optional traction control and system voltage, and speed detectors for failure. The ECU 14 registers these faults and broadcasts or sends the fault status to the DCI unit 12 via the serial diagnostic link J1587. In response to these faults, the DCI microcontroller 72 activates one or more of the LEDs, which are provided in the DCI 12 to indicate faults in the speed detectors, modulators or in the microprocessor ECU 14. One or more discrete LEDs are provided for each of the possible faults detected, so that the mechanic who serves the vehicle immediately can determine, by examining the status of the LEDs in the DCI 12 which of the components of the system is failing. Since many of the faults detected by the aforementioned diagnostic components are of a temporary transient nature, and which are eliminated when there is more is energized when the vehicle is turned off, a non-volatile random access memory in the ECU 14 is provided for storing the faults detected by the aforementioned diagnostics, so that when turning on, when the vehicle is started, the same LEDs are activated again as they were activated immediately before shutting down and transmitted to the DCI unit 12. A reset switch 15, as illustrated in Figure 2, the DCI 12 connects to reset the light emitting diodes when the vehicle has been serviced, and the faults no longer exist. Referring now to Figures 2, 3 and 4, more detailed views are illustrated in the DCI 12, the DCI 12 is an electronic diagnostic tool for locating ABS and ATC faults. The DCI 12 has twelve lamps 50 to 61 and a reset switch 15. The row of ten lamps 50 to 59 is similar to the diagnostic LED display found in some prior Bendix anti-interlock controllers. The lamp 60 indicates the power to the DCI 12 and the lamp 61 indicates that the communication with the anti-interlocking diagnostics of the vehicle is established. The first five lamps 50 to 54 indicate the position of the suspicious appearance in the ABS. The next 4 lamps 55 to 58 indicate an aspect with a suspect component or its wiring. The lamp 59 indicates that there is the correct voltage in ABS ECU. the DCI 12 can be used either on its own or with Acorné software from the company AlliedSignal Truck Brake Systems, which is compatible with Microsoft's Windows software. The DCI 12 can also be used with other compatible diagnostic software. When used alone, the DCI 12 is able to locate individual traction and anti-interlock control faults using lamps 50 to 59 that indicate the defective device or its wiring and location in the vehicle. When used in conjunction with a personal computer with the Acorné software installed, the DCI becomes a communications hub between the numerous onboard vehicle controllers and the personal computer. The DCI 12 includes a serial port connector of the computer 13 to connect to a PC. In this case, all tests and diagnostics are performed by the personal computer and the Acorné software. In order to use the DCI 12, the vehicle must be equipped with a diagnostic link connector J158717. This connector is usually located on the driver's side in a lower portion of the board or under the dashboard panel. To use the DCI 12 by itself, the following procedure should be used to solve problems: 1.- Station the vehicle on a level surface, apply the parking brake and turn off the ignition. 2.- Locate the vehicle diagnostic connector 17 and connect the DCI 20 cable to the vehicle diagnostic connector 17. 3. - Activate the ignition and note that the ten diagnostic lamps 50 and 59 turn on and off according to the system 10 it goes through an automatic test. 4.- The DCI 50 and 61 lamps that remain lit (ON) at the end of the automatic test, indicate the condition of the ANI braking system and the connection between the DCI 12 and the anti-interlock controller 14. For detailed instructions on the use For diagnostic lamps in the DCI 12, a technician can consult the service data sheets for the anti-interlock controller being tested or the vehicle maintenance manual for troubleshooting information. The procedure for using the DCI 12 with the Acorné software installed on a PC 18 are as follows: 1. - Vehicle station to a level surface, apply the parking brake and turn off the ignition. 2.- Locate the vehicle diagnostic connector 17 and connect the DCI 20 cable to the vehicle diagnostic connector 17. 3. - Connect the male end of a serial cable 20 to the serial port DCI 13. 4.- With the PC 18 switched off, connect the other end of the serial cable to an unused serial port on PC 18. 5. - Turn off the ignition and note that the 10 diagnostic lamps 50 to 59, turn on and off as the system passes through a automatic test 6. - Turn on the computer 18 and then open the Acorné software. Test and solve problems of
ABS are made by PC 18 and Acorné software. Now with reference to Figure 5, a block diagram showing the functional relationship of the various DCI sub-systems and components is illustrated. In Figure 6, a detailed electrical schematic of the DCI 12 is illustrated, with portions of the schematic which are marked to correspond with the functional blocks identified in Figure 5. The energy for the DCI 12 is from the vehicle's battery 11. The vehicle's battery supplies more 12 volts energy including earth, through the cable 20 to a regulator +5 volts voltage, 74. The voltage regulator 74 provides an output of +5 volts uniform, constant for the various components of the DCI 12. The output of the regulator 64 turns on the LED 60 which provides a visual indication that there is power to DCI 12. The connection from battery 11 to voltage regulator 64 is via connector J1587, 17. The ABS ECU of vehicle 14 is also connected to DCI 12 via diagnostic link J158 7 through the connector 17. The ABS ECU 14 communicates information to a controller / receiver 82 on the DCI 12 via the link J1587 and the DCI connector 17. The controller / receiver 82 obtains the message from the ECU 14 and conditions the signals of such that they can be understood and processed by a DCI micro controller 12, 72. The controller / receiver 82 also conditions the information signals that are transmitted from the microcontroller 72 to the ABS ECU 14 via the link J1587. The controller / receiver 82 will generate and send an interrupt signal to the microcontroller 62 when there is a message from the ECU 14. The microcontroller will react to the interruption signal to read the information from the controller / receiver 82 and communicate with the ECU 14 The micro controller 72 receives the signals from the controller / receiver 82 which are transported to the controller / receiver 82 from the vehicle diagnostic duct J1587. From the signal head, the microcontroller 62 recognizes and processes the ABS diagnostic communications. If there is an ABS fault, the microcontroller 62 through an LED controller 77 activates particular LEDs 50 to 59 in the LED display 62 to identify the specific ABS fault. The ABS fault is displayed as a message on the LEDs 50 to 59 as previously described. The LED controller 76 supplies pulse current to turn on the appropriate LEDs indicating the fault. When a PC 18 is used with the DCI 12, it is connected to a serial port connector 13. The information ao of the PC 18 is not directly compatible with the microcontroller 72. A controller / receiver 80 and a uART 78 are placed in the connection between the microcontroller 72 and the PC 18. The controller / receiver 80 converts the information of the PC 18 into a recognizable serial format. The uART 78 reads the serial information that is stored in a register and converts the serial information to a parallel format signal that is readable and can be processed by the microcontroller 62. The controller / receiver 80 or the uART 78 also convert the signals of information from the microcontroller 62 to a format that is acceptable to the PC 18. The uART 78 generates and sends an interrupt signal to the microcontroller 72 when there is a message from the PC 18, the microcontroller 72 will react to the signal of interrupt to read the information of uART 78 and communicate with the PC 18. Based on the information received, the microcontroller can act to send messages on the J1587, and turn on some of the LEDs or depending on the received message, do nothing. The DCI 12 can also take information from the J11587 pipeline and send it to PC 18 to display. The uART 78 will convert the information of the microprocessor DCI 72 from a parallel form to a serial form and the controller / receiver 80 will condition the signals in a manner that is acceptable to the PC 18. When the PC 18 is connected to the LED display 62 continuous functioning to indicate ABS and ATC faults. A reset switch for faults 15 is used to send a release message to the ECU 14 when an ABS fault is corrected. A momentary activation of switch 15 will turn off all LEDs 50 to 59 when the current fault is released. If the current fault has been corrected, LEDs 50 to 59 will remain off. If an ABS fault is still present, select LEDs will light to indicate specific ABS faults. If the reset switch 15 is left off for a prolonged period, greater than 15 seconds, the DCI 12 will request the ECU 14 to review a configuration event. This event is self-configuring, allows the ECU 14 to determine the number of detectors and traction control components connected to the system.