Truck with monitored and resettable electronic control units
Contents
1. 364 424 the data link The control unit identifies the installed 4 533 962 8 1985 Decker et al sess 360 5 devices from the transmitted data Data describing the 4 825 362 4 1989 Minami et al 364 200 installed devices including manufacturer model and 4 835 071 5 1989 Sato et al 364 186 installed software can be obtained and displayed for diag 4 843 557 6 1989 Ina et al 364 4311 purposes The instrumentation control unit provides 4 3121847 11 1390 OO EE al centralized reset for resetting the electronic devices on the 5 173 856 12 1992 Purnell et al 364 424 04 data link 5 250 761 10 1993 Koyanagi 177 41 5 303 163 4 1994 Ebaugh et al 364 550 5 345 384 9 1994 Przybyla et al 364 424 04 15 Claims 9 Drawing Sheets 09 cu M CM ID 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 L E LJ LJ LJ LI AIR CONDITIONING POWERTRAIN ANTILOCK 26 AIR SUSPENSION PROTECTION 22 CONTROL 24 BRAKE CONTROL UNIT UNIT UNIT UNIT WARNING UNIT INSTRUMEN CONTROL UNIT 66 68 70 28 COMMUN ICATION UNIT SECURITY ALARM UNIT TATION 72 5 890 080 Sheet 1 of 9 Mar 30 1999 U S Patent 13534 vars gt sss 24 OL 89 99 TO C lHOd v8 ze LINN 28 vivd 08 OHINOO NOLIVLN3IAQH LSNI LINN Wav Iv LINN NOILV2. diagnostic code low character is subsystem identifier SID 0 low character is parameter identifier PID Failure mode identifier FMI of a standard diagnostic code c Occurrence count for the diagnostic code defined by the preceding 2 characters The count is optional and bit 8 of the first character of the diagnostic code is used to determine if it is included Bits 4 1 In some cases it may be helpful to determine additional information about the software installed on the ECUs on the data link PID 234 may be used to obtain additional infor mation regarding software installed on the vehicle PID 234 Software Identification Parameter Data Length Variable Data Type Alphanumeric Bit Resolution ASCII Maximum Range 0 to 255 each character Transmission Update Period On request Message Priority 8 Format PID Data 234 naaa becc n Number of parameter data characters a Software identification field b Optional delimiter ASCII c Optional additional software identification field The software identification field is variable in length and may contain more than one software identification designa tor An ASCII is used as a delimiter to separate multiple software identifications when required If only one software identification field is contained in the parameter the delim iter is not required Additional software identification fields may be added at the end each
3. Sedes a E EPI E TIVHOIVO NIMOY 90409 001651360 L Ove Sjosues UM NOAO MOUS suonounj ej vv 0L V8 Sls Ajuo NDA 5 890 080 Sheet 8 of 9 Mar 30 1999 U S Patent WV Sv 0t 98 5108095 5 85 jejsnjo juauinijsu MOUS suonounj aij 5105095 NOFA 5 890 080 Sheet 9 of 9 Mar 30 1999 U S Patent q 1X9 158 1 Wa Ald CIN Phx 2 989 2 HIDO 151 1X8 Wa Cid AIN PX e SAWIL vec L9OSPESL H290 151 1X9 1 Wa Ald GIN gt lt L 9Grect 15 1 SLINVA HSVG LSIH 8I ULWYd OSG ANON HO L0 v4 3ALLOV X Zt HLINBd 092 2 602 HLNHd 6 Sls A 5 890 080 1 TRUCK WITH MONITORED AND RESETTABLE ELECTRONIC CONTROL UNITS TECHNICAL FIELD The invention relates to a truck including systems for monitoring and resetting electronic control units mounted in the truck BACKGROUND OF THE INVENTION Electronic controls are widely used in trucks for a variety of applications For example sophisticated electronic con trol devices including programmed microprocessors are commonly used to control antilock brake syst
4. whether or not the truck parameter exceeds the threshold In this case a user can scroll through display screens of all historic faults regardless of the value of the truck parameter but he or she could only reset non dash historic faults before the truck parameter exceeds the threshold In addition to the specific approaches described above there are a variety of alternative ways to implement the reset feature As indicated above the truck parameter can be based on engine hours instead of mileage for example The types of fault information e g active and historic faults dash faults or faults on all ECUS etc and the format in which it is displayed e g MID PID FMI can vary as well While we have described the invention with reference to specific embodiments we do not intend to limit the scope of our invention to these embodiments The electronic control units and the data link intercon necting them can be implemented in a variety of ways For example the data link based on SAE 71708 is one possible implementation Other communication media and protocols 10 15 20 25 30 35 40 45 50 55 60 65 20 can also be used to communicate messages between a control unit such as the instrumentation control unit and other electronic subsystems on a truck The instrumentation control unit can also be implemented in a variety of ways For example there are a number of possible user interface designs inclu
5. also includes 256KB of battery backed RAM which is used to implement a FIFO buffer for capturing data from the data link and to store event files In this implementation the data logging unit monitors voltage supplied by the vehicle battery through an analog to digital converter 200 which converts the 12 volt signal from the battery to a digital signal compatible with the microcon troller 184 The real time clock 188 is used to track time in the truck While recording event data the data logging unit time stamps data with the time kept by the real time clock In this implementation the data logging unit is the centralized time keeper for the ECUS on the data link Thus it serves as a common time reference for faults and events that occur in the system The data logging unit performs a data monitoring func tion Coupled to the data link the data logging unit listens for periodic data messages broadcast over the data link The data link continuously records a snapshot of data from the data link into the FIFO buffer In this implementation the data logging unit is programmed to continuously store the most recent 60 seconds of data from the data link Some examples of the data monitored by the data logging unit are set forth below The name of the parameter is followed by the parameter identification number PID as set forth in the SAE J1587 standard Vehicle Road Speed PID 84 Percent Throttle PID 91 Percent Engine Load PID 92 Ou
6. an embodiment of the invention FIG 2 is a block diagram illustrating the instrumentation control unit in an embodiment of the invention FIG 3 is a diagram of a keypad used for input to the instrumentation control unit illustrated in FIG 2 FIG 4 is diagram of the layout of a dash in a truck showing the keypad and display of the instrumentation control unit of FIG 2 FIG 5 is a block diagram illustrating an external com puter coupled to the on board data processing system FIG 6 is block diagram illustrating the data logging unit in one embodiment of the invention FIG 7 is a flow diagram illustrating an embodiment of a method for determining installed components on a truck FIGS 8A and 8B are examples of screen displays used to identify installed electronic components and software on a truck FIG 9 is a diagram illustrating how the ICU can be used to reset electronics devices on a data link in a truck DETAILED DESCRIPTION OF THE INVENTION FIG 1 is a block diagram illustrating the system archi tecture in an embodiment of the invention shown schemati cally on a truck 10 Truck 10 may be conventional with a cab an engine wheels a drive train brakes and other features commonly found on a truck The system architec ture on board the truck includes a number of electronic control units ECU coupled together with a data link 20 In particular the system includes an air conditioning protection unit 22 a powertrain
7. can exhibit erroneous behav lor if not properly reset before delivery to the customer During the truck assembly process an electronic control unit may be used in a manner that makes it think there is a problem or a fault For instance it is common for an assembler to power up an electronic subsystem before installing it in a vehicle In these circumstances the sub system usually generates a number of faults because all of its sensors are not yet installed and calibrated The faults generated during the assembly process can be serious problem for customers and service technicians because they make it appear as if there are problems with the vehicle It is imperative therefore that all of the faults be cleared from the truck s electronics at the truck manufac turing plant This is often time consuming because it may involve entering a series of commands at a keypad just to reset or re program a single device In other cases it may require a technician to connect a hand held diagnostic tool or computer to an electronic subsystem to separately reset electronic subsystems in the truck Often the diagnostic tool or computer require considerable reconfiguration to take advantage of proprietary software from the vendor of the electronic subsystem SUMMARY OF THE INVENTION In one aspect the invention provides a method and apparatus for determining installed electronics on a truck In another aspect the invention provides an improve
8. control unit 24 an antilock brake unit 26 an air suspension control unit 28 a data logging unit 30 and an instrumentation control unit 32 The ECUs on the data link also typically have one or more sensors and actuators 34 76 used to monitor and control performance of the respective subsystems These ECUs represent only one possible system configuration The sys tem can optionally include other ECUs including a collision warning unit 78 a communication unit 80 and a security alarm unit 82 The ECUS on the data link are available from a variety of vendors The powertrain control unit is typically provided by the engine manufacturer Possible sources include Detroit Diesel Corporation of Detroit Mich Caterpillar Inc of Mossville Ill or Cummins Engine Company of Columbus Ind The antilock brake unit is typically provided by the brake vendor such as Allied Signal Truck Brake Systems Co Bendix Elyria Ohio or Rockwell Wabco of Troy Mich The air conditioning protection unit is available from Index Sensors and Controls Inc of Redmond Wash 10 15 20 25 30 35 40 45 50 55 60 65 4 communications unit is a device that supports remote communication with the truck Typical forms of communi cation include satellite cellular short distance radio frequency and infrared These types of communication devices are available from Qualcomm of San Diego Calif Highway Master of Dallas Tex or
9. determine which version of hardware and software is stored on the vehicle In this implementation the installed components can be determined from 1 the ICU or other ECU on the data link or 2 an external computer FIG 5 coupled to the data link 20 via the data port 84 In the first case the ICU or other on board ECU polls the components on the truck to deter mine which ones are present In the second case the external computer polls the components on the truck through the data port and records the response An external computer can be used to download a con figuration file to the ICU including a list of electronic components and possibly software installed in the truck This list can be updated from time to time and can be transferred from memory of the ICU to the external com puter In this implementation configuration files can be transferred between memory of the ICU and an external computer over the data link using the SAE J1587 J1708 protocols In one implementation the ICU determines installed components on the truck by broadcasting a message request ing information from each of the components on the data link and then examining the response To implement this functionality the ICU uses the following parameters set forth in SAE J1587 PID 0 Request Parameter Used to request parameter data transmission from other components on the data link Parameter Data Length 1 Character Data Type Unsigned Short Integer
10. key after the last historic fault 272 a screen is displayed instructing the user how to clear all historic dash faults 274 If the user presses the reset key at this point the ICU will interpret this request differently depending on whether a truck parameter is within predetermined limits If the truck parameter preferably mileage is above the threshold value the ICU will clear historic dash faults The ICU will clear all events and historic faults for the ECUs on the data link only if the truck parameter is below a predefined threshold value As an alternative to mileage the engine hours or other measure e g elapsed time elapsed date can be used to establish a threshold value To evaluate whether the threshold condition for the truck parameter is satisfied the ICU retrieves the current value of the truck parameter and compares it with the threshold value In this implementation the powertrain ECU broad casts the odometer reading periodically on the data link The ICU reads the odometer reading from the data link and maintains its current value in memory In response to a request to clear all dash faults the ICU reads the current mileage reading from its memory and compares it with the threshold value If it is below the threshold value the ICU proceeds to construct messages to clear all faults and events on the truck s electronics If it is above the threshold value the ICU clears all of the historic dash faults If the engin
11. process of determining installed components the polling device can request a response from a specific device on the data link For example the transmitting device can request a response parameter or parameters from a specific component using a message designed according to the J1587 specification for PID 128 This type of message is similar to PID 0 but it also includes the MID of a particular compo nent from which the parameter is requested To poll for installed components using PID 128 a polling device sends a message for each component that it is trying to identify and specifies the MID of that component The polling device can poll for one or more specific devices by transmitting a message including PID 128 the MID of the device and the requested response parameter or parameters e g 194 234 243 etc for each device Generally a polling device can poll for components by making component specific requests for parameters e g PID 128 a non specific request for parameters e g PID 0 or some combination of both Using either a general or device specific request for parameters the polling device compiles list of the installed components by monitoring the data link for responses to its request s for parameter transmission and then interpreting the responses The polling device can also compile a list of missing components by making device specific requests and keeping track of expected devices that do not respond Alterna
12. D intact with the unit serial number being appended to the end of the string where appropriate and necessary 5 890 080 13 continued Delimiters should only appear between the VMRS code and the model fields T X Ex FRGHT _DL U X 2b serial Fields X H S and R should be used for SAE J1587 PID 234 Software ID No delimiters should be used within this PID EX X 2b 003 006 FIG 7 is a flow diagram illustrating an embodiment of a method for determining installed components on a truck This method may be executed by an on board ECU such as the ICU or by an external computer connected to the data link via the data port In the first step a message is constructed including PID 0 and PID 194 As defined above PID 0 is a parameter used to request parameter data trans mission from other components on the data link The first part of the message is the MID of the transmitting device In the case where the ICU is transmitting the message on the data link the MID identifies the ICU as the transmitting device Similarly in cases where an external device is transmitting the message on the data link the MID identifies this external device After the MID the message includes PID 0 which instructs the devices coupled to the data link to transmit one or more parameters identified in the message Following PID 0 the message includes one or more PIDs identifying requested parameters In one implementation where the ICU broa
13. Detroit Diesel FRGHT Freightliner CMMNS Cummins Engine Item Identification Four Alpha characters to define the item Example DL Data logger Century Class Cluster A C Protection _SL ServiceLink note see attached list for UNIT designators Type of Item Single Alpha character to designate kind of item Example U Unit L DLL EXE A API Pre Release Indicator An X in this field indicates item is NOT Released Hardware Platform Double Alpha Numeric character indicates Hardware release and change level or target platform Triple Numeric field identifying function set included in software Software Function Level The following are some possible examples Freightliner Century Class Instrument Cluster released H W level 5 S W level 10 rev 2 Codes as FRGHT CIC U 5 010 002 Data logger released Hardware level 2 revision level b S W level 3 rev 6 Codes as FRGHT DL U 2b 003 006 Rockwell Data logger DLL released version 4 no revision history Codes as DL L 0 004 00 note if a DLL required a specific H W target it could be designated in the field i e 01 Pentium 02 Fieldworks 03 386 Detroit Diesel VEPS EXE released version 8 Codes as DTDSC EC E 0 008 000 ServiceLink API released version 2 rev 4 Codes as FRGHT SL A 0 002 004 As configured the M I T X and H fields can be used in SAE 71587 PID 243 Component I
14. Key 128 4 Set Reset Key 130 The keypad includes an event key 132 which enables the driver to specify that an event or problem has occurred with the vehicle For example if the driver is experiencing problems with the transmission he or she can depress the event key to record the transmission problem In response the data logging unit 30 receives an interrupt signal from the keypad 90 of the ICU and creates an event file In this implementation there is a discrete connection 110 from the keypad 90 to the data logging unit 30 In addition the ICU can send a message to the data logging unit over the data link 20 to notify it that the driver or other user has triggered a manual event at the keypad 90 As explained in further detail below the keypad on the ICU can be used in conjunction with diagnostic display screens to clear faults and events from a central location FIG 4 is a diagram illustrating the layout of the dash in one embodiment The dash includes a variety of gauges 133 136 for example and indicator lights 137 for example The display device 138 of the ICU is positioned in front of the driver as shown The keypad 139 of the ICU is positioned to the right of the display within reach of the driver This layout illustrates only one possible layout of the dash and many other variations are possible FIG 5 is a block diagram illustrating an external com puter system coupled to the on board data processing sys tem Servi
15. OI LINN ONINHVM NOISITIOO ALlHnoas NOWNINOO 92 vl 02 8c LINA LINN LINN TOHLNOO TOHLNOO NOILO3 LOUd NOISN3dSNS HIV MOOTLLNV NIVH LH3MOd ONINOILIGNOO LI O O ES OJ u Q c9 09 8S 99 vS cS 0S 8b Op 8E 9 VE U S Patent Mar 30 1999 Sheet 2 of 9 5 890 080 DOOR HVAC PARKING SENSORS SENSORS SENSORS 98 COOLANT 96 LEVEL SENSOR 100 WIPER FIG 2 AID FLUID CONVERTERS SENSOR 102 106 TURN SIGNALS 110 90 TO DATA DISPLAY LOGGING UNIT KEYPAD DEVICE o LI INTERFACE 108 e 5 890 080 Sheet 3 of 9 Mar 30 1999 U S Patent 5 890 080 Sheet 4 of 9 Mar 30 1999 U S Patent 9v AGNON QHVOSA3M 3OIA3Q LAdNI VIVO OL LHOd jOIA3Qd LINA AYVONOOAS 5 15199 AYOWAW NIVIN 5 890 080 Sheet 5 of 9 Mar 30 1999 U S Patent sous OHS 961 5 Nee E AHONEN H31H3ANOO 32019 av Wad 00 DOTEE EN Ns sl 861 261 E ova 0 H3TIOHLNOO H355lH L OHOIN TWANVA 78 ogi 06l dans H3MOd 9 SIs U S Patent Mar 30 1999 Sheet 6 of 9 5 890 080 BUILD MESSAGE INCLUDING PID 0 PID 194 AND POSSIBLY PID 234 AND PID 243 210 5 890 080 Sheet 7 of 9 Mar 30 1999 U S Patent
16. Resolution Binary Maximum Range 0 to 255 Transmission Update Period As needed Message Priority 8 Format PID Data 0 a a Parameter ID of the requested parameter PID 194 Transmitter System Diagnostic Code and Occurrence Count Table Parameter Data Length Variable Data Type Binary Bit Mapped Resolution Binary Maximum Range 0 to 255 Transmission Update Period The diagnostic code is transmitted once whenever the fault becomes active and once whenever the fault becomes inactive but never more than once per second All diagnostic codes are also available on request All active diag nostic codes are retransmitted at a rate greater than or equal to the refresh rate of the associated PID but not greater 5 890 080 11 continued than once per second Active diagnostic codes for on request PIDs and SIDs are transmitted at a rate of once every 15 seconds Message Priority 8 Format PID Data 194 nabcabcabcabcabcabc n Byte count of data that follows this character This excludes characters MID PID 194 and n but includes a b and c type characters a SID or PID of a standard diagnostic code b Diagnostic code character Bit 8 Occurrence Count included count is included 0 count not included Current Status of fault fault is inactive 0 fault is active Type of diagnostic code standard diagnostic code 0 expansion diagnostic code PID PID from page 2 Low character identifier for a standard
17. Rockwell Transportation Electronies of Cedar Rapids Iowa The collision warning unit is responsible for warning of possible collisions It is available from Eaton Vorad Tech nologies of San Diego Calif system architecture in FIG 1 also includes a data port 84 for coupling external devices to the on board data link This data port 84 enables an external computer to receive and transmit messages on the data link It also enables an external computer to establish a connection with an ECU on the network to either download data or retrieve data from memory in an ECU on the data link The data link 20 in this implementation is a serial communication path connecting the ECUS together This particular data link is designed according to SAE J1708 a standard for serial data communication between microcom puter systems in heavy duty vehicle applications While this specific embodiment is based on the J1708 standard it is not critical that the invention be implemented in this specific manner One possible alternative is to use a data link constructed according to SAE J1939 In one specific embodiment the data link 20 is comprised of a twisted pair cable operating at 9600 baud Designed according to the SAE 11708 standard the data link forms a communication channel among electronic control units coupled to it Electronic control units generate a digital signal on the data link by applying a voltage differential between the two wires in th
18. US005890080A 54 75 73 United States Patent Patent Number 5 890 080 Coverdill et al 4 Date of Patent Mar 30 1999 TRUCK WITH MONITORED AND 5 365 436 11 1994 Schaller et al 364 424 03 RESETTABLE ELECTRONIC CONTROL 5 693 876 12 1997 Ghitea Jr al 73114 UNITS OTHER PUBLICATIONS Inventors Cary N Coverdill Boring Oreg Owner s Manual Caterpillar Driver Information Display Steven A Wright Charlotte N C Caterpillar Feb 1995 ProDriver User Manual Detroit Diesel Corporation Mar Assignee Freightliner Corporation Portland 1994 Oreg CELECT RoadRelay User s Guide Cummins Cadec copyright 1993 Appl No 673 697 inis Primary Examiner Michael Zanelli Filed Jun 25 1996 Attorney Agent or Firm Klarquist Sparkman Campbell Int CLP 19 00 17 00 Leigh amp Whinston LLP V S Cl utendo 701 29 701 33 701 32 57 ABSTRACT Field of Search 701 29 31 32 701 36 50 33 340 459 461 462 A method for determining installed electronic devices on a truck and for providing a centralized reset to clear faults in References Cited the installed electronics An instrumentation control unit in the cab of a truck determines installed electronics by U S PATENT DOCUMENTS requesting electronics on a shared data link to transmit data 4 258 421 3 1981 Juhasz et al
19. a message is limited by the total message length defined in the SAE J1708 standard The module identification numbers are assigned to transmitter categories as identified in SAE J1587 The MID portion of a message specifies the origin or transmitter of the message In the majority of cases messages are broadcast on 5 890 080 5 the data link without specifying a receiver However the message format can be extended to include the MID of a receiver after the MID of the transmitter for special appli cations The messages passed among the ECUs convey informa tion by one or more parameters contained within them According to the SAE J1587 standard the first character of every parameter is a parameter identification character PID The parameter identified by the PID directly follows the PID The SAE 71587 supports different data formats including a single character a double data character or more than two data characters representing the parameter data Several parameters can be packed into a message limited in this specific example by the maximum message size as noted above In this implementation the ECUs 22 32 78 82 commu nicate with each other over the data link 20 according to the SAE standard J1708 The standard describes methods for accessing the data link and constructing messages for trans fer over it It also defines a method for resource contention among the ECUS on the data link An ECU wishing to transmit data on the da
20. an ECU or other responding elec tronic component on the data link that is not identified on the expected list In a typical case the truck manufacturer generates the expected list of components based on the components that it has installed in the vehicle The expected list can be stored on board the vehicle such as in a file in memory of the ICU or data logging unit or it can be stored off the vehicle such as in a manufacture s or dealer s database along with a vehicle identification number The results of the polling and comparing steps can be displayed so that a user can view a description of the installed missing or unknown components 222 For example in one possible implementation the ICU displays ECU data identifying the unknown and missing ECUs The external computer executing an application such as Service Link from Freightliner Corp can also display a list of installed unknown or missing components There are a number of possible variations to this approach For example another ECU on the data link can compile the list of the installed components and the ICU can read the list compare it with expected components and display information about the installed missing or unknown components on the display device Conversely the ICU can store a list of the installed components and another device such as the external computer can retrieve it compare it with an expected list and display installed missing or unknown
21. ce technicians or other users can use an external computer coupled to the data link to analyze the electronics and software on board the truck In one implementation the external computer is an IBM compatible PC equipped with the Windows Operating System from Microsoft Corporation and ServiceLink diagnostic software from Freightliner Cor poration ServiceLink is one example of an application program used to communicate with ECUS e g the data logging unit and ICU on a SAE 171587 data link Other software applications such as JTools and JPro from Parasoft Computing Solutions Winston Salem N C also can be used to communicate with an ECU on a J1587 data link A variety of alternative computers and computer architectures are also possible as evidenced by the general nature of the computer architecture shown in FIG 5 The computer system 140 includes as its basic elements a computer 142 a display device 144 an input device 146 and serial communication link 148 to the data port 84 on the data link 20 The external computer 142 generally includes at least one high speed processing unit CPU 150 and a memory system 152 that communicate through a bus structure 154 CPU 150 includes an arithmetic logic unit ALU 156 for performing computations registers 158 for temporary storage of data and instructions and a control unit 160 for controlling the operation of computer system 140 in response to instructions from a computer program such as an a
22. ck diagram illustrating the instrumentation control unit ICU in an embodiment of the invention As explained in further detail below the ICU can be used to check electronic components installed on the truck Although it may be located anywhere on the truck the ICU is typically positioned in the truck cab for easy access and most preferably at the dash of the truck It can also be used to reset faults and events The instrumentation control unit includes a CPU 0 memory 82 and a port interface 84 for connecting the unit to the data link 20 The memory includes programmable ROM EEPROM 86 and permanent ROM 88 The routines for controlling the ICU are stored in ROM 88 while urable data such as a configuration file is stored in the EEPROM 86 The memory 82 also includes a form of volatile memory such as RAM 87 for temporary storage of program instructions and data In one specific implementation the ICU has two CPUs and its memory includes EEPROM ROM and RAM The 10 15 20 30 35 45 50 55 60 65 6 CPUs are 68HC11 microprocessors from Motorola Corpo ration A first CPU controls the operation of the message display system and executes routines to determine installed components and to clear faults of ECUs on the data link and stored events in the data logging unit The second CPU controls dash instrumentation integrated with the ICU The second CPU is not critical to the invention but is menti
23. components The ICU or other polling device can also maintain a list of related information for the installed or unknown components such as the fault information from PID 194 software information from PID 234 and make and model information from PID 243 This related information can be used to convey more information about the installed components when displayed to a user such as on the display of the ICU or on a display screen or printout generated by an external computer coupled to the data link The method described above enables a device on the data link to determine which components are installed on board the truck The information returned in response to a request for PIDs 234 and 243 enables a service technician to determine whether the components and software installed on the vehicle are compatible with each other One particular program for retrieving and displaying diagnostic information from the data link is called Service Link from Freightliner Corporation ServiceLink diagnostic software is a PC based program used to retrieve diagnostic 10 15 20 25 30 35 40 45 50 55 60 65 16 data from devices connected to the data link on board a truck The ServiceLink diagnostic software communicates data to and from the vehicle Specifically it is capable of reading faults from ECUs on the data link It can also retrieve event files from the data logging unit and also display data from this event file as we
24. d method for resetting the truck electronics In one specific embodiment of the invention a truck is equipped with a number of electronic control units ECUs interconnected via a truck data link The ECUs are instructed to transmit data via the truck data link By analyzing this data a computer coupled to the truck data link can identify the installed components Further data about the model manufacturer and installed software can also be determined In this specific embodiment the system architecture on the truck includes an ECU called the instrumentation control unit located in the cab of the truck The instrumentation control unit or an external computer coupled to the data link can query the ECUs on the data link to determine which components are installed and to obtain more specific data about the installed components For example in one method for determining installed components the instrumentation control unit broadcasts a request for data transmission on the data link and then monitors the responses from the installed components The instrumentation control unit identifies the installed components from their responses and stores a list of the installed components This list can be downloaded to an external computer using diagnostic software and can be displayed for use in analyzing the compatibility of the installed components The instrumentation control unit provides a convenient method for resetting the installed electronic con
25. d to respond to this request will return a data string including a software identification field such as the one set forth above in the specification of PID 234 The software identification field is variable in length and may contain more than one software identifica tion designator If PID 243 is requested in the message broadcast to devices on the data link a device programmed to respond to this message will return data specifying their make model and serial number The detailed SAE 71587 specification of parameter 243 is provided above A request for parameters 234 and 243 is particularly well suited for service applications where the data is extracted from the on board devices via an external com puter An external computer such as a PC has greater memory and processing capacity to store and display addi tional data about the devices on the data link for diagnostic purposes An ECU on the data link such as the ICU for example can also be programmed to retrieve and possibly display this data as well After broadcasting the request for data as described above the polling device listens for the response and records the data returned by the devices on the data link 214 216 The polling device e g the ICU other on board ECU or an external computer continues to listen for and record responses through its port interface for a predetermined period of time At the end of this period 218 it stops listening for further messages In the
26. d within a cab of the truck the method comprising in response to a user request to display diagnostic data entered at the input device displaying diagnostic data including a description of one or more faults from the electronic control units on the display device and in response to a user request entered at the input device to clear a fault determining whether mileage or engine hours are below a predefined value and if so instruct ing the electronic control units coupled to the data link to clear faults 11 The method of claim 10 wherein one of the electronic control units comprises a data logging unit for monitoring and recording predefined events and wherein the step of instructing the electronic control units to clear faults includes instructing the data logging unit to clear faults and predefined event recorded in memory of the data logging unit 10 15 20 25 30 35 40 22 12 A method of resetting a plurality of electronic control units in a truck the electronic control units each being coupled to a data link in the truck the method comprising establishing a reset threshold for a truck parameter determining whether the reset threshold for the truck parameter has been satisfied and sending a reset signal along the data link when the reset threshold has been satisfied 13 A method of claim 12 wherein the reset threshold is a predetermined truck mileage and wherein the step of deter mining
27. dcasts the message the message includes at least PID 194 and may also include request for PIDs 234 and 243 In another implementation where the external computer broadcasts the message additional PIDs are included to obtain more information about the installed components Specifically the message includes PID 234 and 243 in addition to PID 194 It should be noted that these specific requests for parameters are not necessary to imple ment the invention The requesting device can detect an installed device from the MID that it returns in a response message to a request for a parameter PID 194 is useful because it gives fault information PIDs 234 and 243 are useful because they provide additional information about installed software and make model respectively After building a message the transmitting device also referred to as the device broadcasts the message to the components on the data link as shown in step 212 Each of the components on the data link that are operational should reply to this message If a receiving device has no diagnostic codes to transmit it returns PID 194 with the n parameter set to zero If a receiving device has one or more faults however it returns PID 194 with additional diagnostic codes providing additional information about a fault or faults in the device In the SAE 1587 specification of PID 194 diagnostic data returned for PID 194 can include 1 a subsystem identification number SID o
28. ding different display devices and display for mats as well as different keypad or keyboard configurations Having described and illustrated the principles of our invention with reference to a preferred embodiment and several variations thereon it should be apparent that the invention can be modified in arrangement and detail without departing from its principles Accordingly we claim all modifications as may come within the scope and spirit of the following claims We claim 1 In a truck having a plurality of installed electronic control units coupled to a data link a method for determin ing which electronic control units are installed on the truck the method comprising from a computer coupled to the data link issuing a request for data transmission on the data link monitoring the data link for responses from the installed electronic control units receiving the responses from the installed electronic con trol units interpreting identities of the installed electronic control units on the data link from the responses compiling a list of the installed electronic control units storing the list of the installed electronic control units comparing the list of the installed electronic control units with a list of expected electronic control units and displaying information about missing or unknown elec tronic control units 2 The method of claim 1 wherein the computer comprises an instrumentation control unit located i
29. e cable A voltage differential above a specified threshold represents a logic high value while a voltage differential below a specified threshold represents a logic low value This type of data link is particularly advantageous for hostile environments because the signal is more robust and impervious to signal degrada tion However other alternative communication media could be used in place of the J1708 cable The ECUs connected on the network communicate with each other according to protocols defined in SAE J1708 and SAE J1587 The SAE J1587 standard is entitled Joint SAE TMC Electronic Data Interchange Between Micro computer Systems and Heavy Duty Vehicle Applications This standard defines the format of data and messages communicated among microprocessors connected to a shared data link and is specifically adapted for use with SAE J1708 According to SAE J1708 J1587 the ECUs 22 32 78 82 on the data link 20 communicate by passing messages to each other The ECUs can be either receivers or receivers and transmitters In this particular implementation the instrumentation control unit 32 is a transmitter and a receiver It acts as a transmitter when requesting data from or resetting the ECUs on the data link 20 and acts as a receiver when listening for data transmitted from other ECUs A message in this format includes the following 1 a module ID MID 2 one or more parameters and 3 a checksum The number of parameters in
30. e hours are used as the truck parameter that establishes the threshold value the ICU performs a similar function as described above The ICU obtains the engine hours from the powertrain ECU and compares the current value for engine hours with the threshold value The ICU can obtain the engine hours either by specifically requesting the parameter from the powertrain ECU or by listening for a periodic broadcast of the engine hours parameter In the latter case the powertrain ECU is programmed to broadcast the engine hours parameter The purpose for using either truck mileage or engine hours in these circumstances is to establish a limited mileage or time in proximity to the manufacture of the truck during which historic faults may be cleared or reset Truck mileage and engine hours are candidates because they can be used to specify a limited period during which the reset feature is active within a reasonable proximity to the assembly of the truck Limiting the period during which this reset feature is active has a number of advantages It enables all faults and events to be reset easily without requiring special purpose diagnostic tools to reset each of the ECUS separately Because it is available for a limited duration in proximity to the truck s assembly it can be used for the specific purpose of clearing faults erroneously generated during assembly The limited duration of the reset feature precludes users from intentionally or inadvertentl
31. ems powertrains and transmissions These electronic devices have provided new functionality such as the antilock brake systems and have improved performance of existing com ponents While electronics have significantly improved functionality and performance they have also increased the complexity of trucks As the use of electronic systems in trucks has grown a number of electronic control devices or units have been developed for specific applications For example engine manufacturers have designed special purpose computers for controlling and monitoring engine performance Brake manufacturers have designed electronic control devices to control sophisticated antilock brake system Still other manufacturers have developed control units for air suspen sion systems Since each of these devices are designed for different purposes they are not typically designed to work together or to communicate with each other With the increasing sophistication of truck electronics a need arose to provide a means for communicating data from the disparate electronic control systems on board the vehicle Two standards developed for communication between electronic devices in vehicles are SAE Society of Automotive Engineers 11708 and 11587 SAE 11708 defines the requirements of the hardware and basic protocol for communicating data between electronic control systems or units SAE J1587 provides a common format for mes sages and data communicated between t
32. ents it has generated This is a useful feature that enables the data logging unit to be reset from another device on the datalink Below we describe how the ICU or an external computer can be used to determine installed components on the data link We also describe how the ICU can be used to reset the truck s electronics and clear stored events in the data logging unit Installation of Electronics 10 15 20 25 30 35 40 45 50 55 60 65 10 In a typical case the manufacturing process proceeds as follows In processing an order for a new truck the main frame computer at the manufacturing plant generates a detailed truck specification The creation of the specification triggers a number of manufacturing processes necessary to build the truck according to the specification Before deliv ery of the finished truck a list of electronic components installed on the truck is prepared This list is configured into a file format compatible with the ICU on board the truck From an external computer the component list is down loaded into the memory of the ICU Later the electronics on the truck are sometimes modified making them incompat ible As a result the electronic devices listed in the configu ration file may not be consistent with the electronic devices actually installed on the vehicle To diagnose these compat ibility problems it is necessary to determine whether the electronics have been modified and to
33. gnal is applied The specific sensors used in this embodiment are not critical to the invention These sensors are illustrated to demonstrate that ECUs can include a variety of sensors and or actuators During installation or repair sensors such as these can generate faults in their respective ECUs These types of faults need to be cleared to ensure that the data management system on board the vehicle is operating prop erly The ICU can also include a buzzer 108 used to notify the driver when certain warning conditions are detected Typical examples of these warning conditions include cab door open parking brake applied and vehicle in motion coolant level low etc In this implementation the buzzer is integrated into the ICU However a buzzer or other audio transducer can be implemented as a discrete device to the ICU The particular ICU used in this implementation is manu factured by Joseph Pollak of Boston Mass for Freightliner Corporation The instrumentation control unit is presently available as a replacement part from Freightliner Corpora tion FIG 3 is a diagram of one implementation of the keypad The illustrated keypad includes the following dedicated keys 1 Time 114 2 Temperature 116 3 Fuel 118 4 Trip Miles and Hours 120 5 Leg Miles and Hours 122 The keypad also includes the following general purpose keys 5 890 080 7 1 Left Arrow Key 124 2 Down Arrow Key 126 3 Right Arrow
34. he electronic control systems Despite the adoption of these standards by many in the industry they alone do not solve many problems associated with installing and servicing electronic devices on today s trucks For example the standards do not provide any mechanism for determining which components are installed or for determining whether the installed components are compatible One problem associated with these electronic systems is ensuring that they function properly and that they are compatible The truck manufacturer can build and test the electronics to make sure that they are operational However it is very common for others to modify the truck with after market electronic parts which do not operate properly or are incompatible with other components In these circumstances it is likely that the truck will have a number of electronic components that have never been tested by the truck manufacturer lack of proper installation of electronic controls is major problem for truck manufactures and service providers Studies show that in excess of 5046 of electronic compo nents returned are found to operate properly such considerable time and money is wasted in addressing prob lems that could have been avoided had the electronics been installed and configured properly 10 15 20 25 35 40 45 50 55 60 65 2 Another problem associated with electronic devices installed on trucks is that they
35. he specification for PID 195 is set forth below PID 195 Diagnostic Data Request Clear Count Parameter Data Length 3 Characters Data Type Binary Bit Mapped Resolution Binary Maximum Range 0 to 255 Transmission Update Period As needed Message Priority 8 Format PID Data 195 nabe n Number of parameter data characters 3 a MID of device to which request is directed b SID or PID of a standard diagnostic code c Diagnostic code character Bits 8 7 00 Request an ASCII descriptive message for the given SID or PID 01 Request count be cleared for the given diagnostic code on the device with the given MID 10 Request counts be cleared for all diagnostic codes on the device with the given MID The diagnostic code given in this transmission is ignored 11 Request additional diagnostic information for the given diagnostic code the content of which is defined in a manufacturer s application document Bit 6 Type of diagnostic code 1 standard diagnostic code 0 reserved for expansion diagnostic codes Bit 5 Low character identifier for a standard diagnostic code 1 2 low character is subsystem identifier SID 0 low character is parameter identifier PID Bits 4 1 Failure mode identifier FMI of a standard diagnostic code In response to receiving PID 195 which includes an instruction to clear faults the ECUs on the data link clear their historic faults The data logging unit clears any hi
36. he user has reached the diagnostic information screen 250 he can retrieve active faults by pressing the right arrow key 252 In general an active fault is a fault where the condition generating the fault still exists or in other words is currently active An active fault is in contrast to a historic fault which represents a fault that has occurred but is not currently active In this implementation the active faults include all of the active faults from the ECUS on the data link including the ICU The fault screens 5 890 080 17 show the message identifier MID parameter identifier PID and failure mode identifier followed by an abbreviated description of each fault If the user continues to press the right arrow key he or she will scroll through the active faults 254 258 At any point while viewing the active faults the user can access historical faults 260 by depressing the down arrow key 262 for example on the keypad Using the left and right arrow keys the user can scroll through each of the historic faults 264 266 The historic fault screens show the MID PID FMI and possibly related text describing the fault While viewing the historical faults the user can obtain additional information about the occurrence of the fault such as when the fault occurred 268 and the number of times it occurred by pressing the down arrow key as shown 270 for example If the user presses the right arrow
37. ll as faults from the ECUs on the data link FIGS 8A and 8B illustrate examples of display screens showing diagnostic information retrieved and displayed using the ServiceLink diagnostic software FIG 8A is a screen diagram illustrating a list of ECUs and corresponding data describing the manufacturer model and software version For example the first row 240 lists the engine ECU manufactured by Caterpillar CTRPL The model number is 3406E and the version of the software installed on the ECU is V1 0 FIG 8B is a similar diagram illustrating ECUS as well as the sensors coupled to the respective ECUs As an example consider the fourth row 242 of the table The term instru ment cluster refers to the ICU in this implementation For this entry in the table the screen display shows the manu facturer PLLCK the model ROADRUNNER and the software version number v1 8 The table then lists a number of sensors 244 attached to the ICU Resetting Installed Systems In addition to determining installed hardware and soft ware on the truck the invention also provides a method and system for resetting the installed devices As noted above a number of faults are typically generated during the assembly process If these faults are not cleared before delivery to the customer devices on board the truck can show faults even though they are installed properly and are compatible with other devices In addition to clearing faults it i
38. n a cab of the truck wherein the instrumentation control unit is coupled to a display device and wherein the displaying step includes displaying the infor mation about the missing or unknown electronic con trol units on the display device 3 The method of claim 2 further including downloading a file including the list of the installed electronic control units from memory of the instrumen tation control unit to memory of an external computer coupled to the data link and displaying the list of the installed electronic control units on a display device of the external computer 4 The method of claim 1 wherein the computer comprises an external computer located outside the truck and coupled to the data link through data port on the data link 5 The method of claim 1 wherein the data link is a serial communication link 6 The method of claim 1 wherein the step of issuing a request on the data link includes building a message listing one or more parameters to be returned by the installed electronic control units on the data link and broadcasting the message on the data link 7 The method of claim 6 wherein the message includes first parameter to instruct the installed electronic control units to return a software identification parameter 8 The method of claim 6 wherein the message includes a first parameter to instruct the installed electronic control units to return manufacturer and model parameters 9 In a truck ha
39. ntation of the diagnostic screens used to display and clear faults can vary The ICU can be programmed to provide different diagnostic screens before and after the threshold value is attained For example in one embodiment the ICU displays diagnostic information based on whether the value of the truck parameter exceeds the threshold value In response to a request to display fault information at diagnostic screen 250 in FIG 9 for example the ICU displays all active and historic faults or only active and historic dash faults depending on whether the truck parameter exceeds the threshold value Dash faults in this context refer to the faults that the ICU can detect within its own subsystems and sensors For example a broken wire between the ICU and one of its sensors such as sensors 94 104 shown in FIG 2 constitutes a dash fault In one embodiment the ICU determines which types of faults to display based on the comparison between the current value of the truck parameter and the threshold value If the current value of the mileage parameter is below the threshold for example the ICU will display active and historic faults including dash and non dash faults in response to user input as shown in FIG 9 If the current value of the mileage parameter is beyond the threshold the ICU will display only the active and historic dash faults In an alternative implementation the ICU can be pro grammed to display all historic and active faults
40. oned here to be complete This specific ICU has 8 KB of external EEPROM 128K of ROM and 2K of RAM The internal memory of the CPU comprises 256 Bytes of RAM and 512 bytes of EEPROM This is only one specific implementation of the ICU A variety of conventional processors and memory systems can be used to implement the functionality of the instrumentation control unit ICU also includes an input device 90 and a display device 92 In this implementation the input device 90 is ten key keypad The display device 92 presents a two line display sometimes referred to as the message center In one implementation the display device comprises a two by 20 character vacuum fluorescent VF display Alternative implementations are also possible such as a liquid crystal display LCD or other display device The ICU in FIG 2 is connected to a number of sensors 94 104 through analog to digital converters 106 For example the ICU in this implementation is coupled to door sensors 94 for detecting when the cab doors are open or closed HVAC sensors 96 for determining whether fresh air is circulating in the cab parking brake controls 98 for sensing whether the parking brakes are applied a coolant level sensor 100 for detecting when the coolant level drops below a specified level wiper fluid sensors 102 for deter mining when the wiper fluid drops below a specified level and turn signal controls 104 which indicate when a turn si
41. pplication or an operating system Any of a variety of processors including those from Digital Equipment Sun IBM Motorola NEC Intel Cyrix AMD and Nexgen can be used as the CPU 150 Although shown with one CPU 150 computer system 140 may alternatively include multiple processing units Memory system 152 generally includes high speed main memory 162 in the form of a medium such as random access memory RAM and read only memory ROM semicon ductor devices and secondary storage 164 in the form of a 10 15 20 25 30 35 40 45 50 55 60 65 8 medium such as floppy disks hard disks tape CD ROM etc and other devices that use electrical magnetic optical or other recording material Main memory 162 stores programs such as a computer s operating system and currently running application programs Main memory 162 also includes video display memory for displaying images through a display device Input device 146 and the port 148 to the data link 20 are peripheral devices connected by bus structure 154 to com puter 142 Input device 146 may be a keyboard a pointing device such as a mouse a pen or other device for providing input data to the computer It should be understood that FIG 5 is a block diagram illustrating the basic elements of a computer system the figure is not intended to illustrate a specific architecture for a computer system 140 For example no particular bus structure is shown beca
42. r a parameter iden tification number PID of a standard diagnostic code 2 a diagnostic code character and 3 an occurrence count for the diagnostic code The specific structure of the diagnostic code characters 15 provided above in the referenced J1587 speci fication of PID 194 To summarize briefly the diagnostic code character includes a failure mode identifier FMI used to identify a standard diagnostic code a bit indicating whether fault data is provided for a parameter identifier or a subsystem identifier the status of the fault active or inactive and whether an occurrence count is included The occurrence count specifies the number of times a particular fault has occurred For the purpose of determining the installed components it is not critical whether the receiving devices on the data link return a zero or detailed diagnostic data in response to 10 15 20 25 30 35 40 45 50 55 60 65 14 the request for PID 194 The device requesting this data whether it is the ICU or an external computer is looking for response to determine which components are present on the data link A response message from an ECU includes a MID which the polling device can use to determine the installed components To obtain additional information about installed components the polling device can also request information using PID 234 and 243 In response to a request for PID 234 receiving device programme
43. s also important to clear any events that have been recorded prior to delivery For example in one implementation a data logging unit on board the truck may have recorded one or more events triggered during the assembly or testing process of the vehicle at the manufacturing plant In one embodiment the instrumentation control unit provides a method for clearing faults in the ECUs on the data link as well as resetting events recorded in the data logging unit An assembler can easily clear faults and events using the keys on the keypad of the ICU to retrieve diagnostic information stored in the ICU and to reset faults FIG 9 is a diagram illustrating a sequence of displays presented by the ICU in response to user input during a method for clearing faults and events on board a truck In this implementation the user first has to access the diag nostic information screen accomplish this power has to be applied to the vehicle and the parking brake has to be applied It is not critical to the invention that the parking brake be applied during this operation However it is an additional safety feature implemented to prevent users from trying to access more detailed information while driving In this particular implementation shown in FIG 9 the user scrolls through a variety of stationary access screens using the down arrow key on the keypad One of the stationary access screens is referred to as diagnostic infor mation 250 Once t
44. separated by an ASCII as delimiter If the software identification for a particular product exceeds 18 bytes then PID 192 shall be used to section this parameter For information about the make model and serial number of the components installed on the truck PID 243 may also be included in the message broadcast to the components on the data link 10 15 12 PID 243 Component Identification Parameter Parameter Data Length Variable Data Type Alphanumeric Resolution ASCII Maximum Range 0 to 255 each character Transmission Update Period On request Message Priority 8 Format PID Data 243 nbocccece dddddddddd eeceeeeecece n Number of parameter data characters following this byte b MID of component being identified c Characters specifying component Make d Characters specifying component Model e Characters specifying component Serial Number data returned in response to a request for PID 234 and PID 243 can be further improved if provided in the follow ing format 0 30 35 40 45 60 65 Format MMMMM IIII T X HH SSS RRR Rev Level Software Function Level Hardware Platform Level Pre Release Indicator Type of Item Item Identification Manufacturer Designator where the above fields are defined as follows Manufacturer Designator Five Alpha characters providing ATA VMRS code or a pseudo code for non vehicle manufacturers Example RCKSST Rockwell DIDSC
45. storic faults it has generated in response to PID 195 and clears any events in response to a another message instructing it to clear its stored events In one implementation the ICU builds a 5 890 080 19 message specifically designed to clear stored events in the data logging unit In response to this message the data logging unit clears its stored events For example if a manually triggered event has been triggered this event is cleared the corresponding event file is cleared and the data logging unit is reset The specific format of the message to clear stored events can vary In one implementation the message includes a MID of the transmitter ICU for example the number 254 the MID of the data logging unit the message length the number 17 the event class and a check sum In this example the event class parameter enables the data logging unit to clear events by classes Clearing an event of a particular class causes the clearing of events in subordinate classes For example clearing class 1 events implicitly clears events in classes greater than 1 classes 1 2 and 3 Clearing class 2 events clears events in classes 2 and 3but not in class 1 The data logging unit responds with the same message to acknowledge that the stored events have been cleared If the data logging unit is unable to clear the requested events the response message will indicate this by setting the event class parameter to zero The specific impleme
46. ta link
47. ta link first waits for a lull in transmission of data on the data link In this particular implementation the length of the lull is 200 milliseconds After detecting this lull the ECU attempts to transmit its message The transmitter broadcasts its message onto the data link Each of the ECUS that operate as receivers on the data link will receive the message However receiv ers only act on a message if programmed to do so In some cases two or more transmitters may attempt to broadcast a message at one time giving rise to a collision To resolve a conflict among transmitters messages have a priority according to their message identifiers The MIDs of higher priority transmitters have a greater number of bits set at a logic level one When more than one message is broadcast at a time the more dominant message takes priority over lesser dominant messages Since a lower pri ority message is blocked by a higher priority message the transmitter of the lower priority message waits and retrans mits the message after another lull An ECU on the data link will continue to attempt to send a message until it is successfully broadcast to the data link While this particular embodiment is implemented accord ing to the SAE J1708 standard this is only one example of the media that can comprise the data link 20 Other alter natives are possible as well For example the data link 20 can be implemented according to SAE J1939 as well FIG 2 is a blo
48. tively the polling device or possibly some other device using the results of the polling step can identify missing components by comparing a list of installed com ponents with a list of expected components as explained further below 5 890 080 15 The specific method for interpreting the responses depends in part on the method for requesting responses If the polling device makes a request for parameters using PID 0 and PID 194 for example it can identify installed com ponents from the MIDs in the response messages If the polling device makes a component specific request using PID 128 for example it can determine whether the device having the specified MID is installed by receiving a response from it The polling device can get more information about installed components than just the MID from additional requested data in the response message such as the installed software or the hardware make and model In one specific implementation the ICU interprets the MID of the devices responding to a general request for parameter transmission and keeps a list of the installed components The ICU compares the list of installed com ponents with a list of the expected electronic control units expected list 220 The two lists are compared to identify any unknown or unexpected ECUs that have responded to the transmitting device and to determine whether any expected ECUs have not responded The term unknown in this context refers to
49. tput Torque PID 93 Engine Oil Pressure PID 100 Turbo Boost Pressure PID 102 Coolant Temperature PID 110 Engine Speed RPM PID 190 For some types of data the data logging unit captures a new instance or slice of data once every second and stores it in the buffer When the buffer is full the most recent second of data overwrites the oldest snapshot of data In addition to continuously storing the data listed above the data logging unit also monitors predefined events These events can be defined by a PID broadcast on the data link or by a discrete signal such as an interrupt received at the data logging unit When one of the predefined events occurs the data logging unit stores the last 60 seconds worth of data to memory and begins storing the next 60 seconds worth of data In total in this example the amount of data stored for an event includes two minutes and one second worth of data This data is recorded in an event file in memory An external computer can be coupled to the data link to extract one or more event files from the data logging unit The data logging unit is programmed to respond to a request for data from the ICU or other computer on the data link such as an external computer This functionality enables the ICU or external computer to verify that the data logging unit is installed properly and is compatible with other devices on the data link The data logging unit can also be programmed to clear any faults or ev
50. trol units on the vehicle The user can access and display diagnostic data called faults via an input device coupled to the instrumen tation control unit in the cab of the vehicle In response to a command entered by the user the instrumentation control unit instructs the electronic control units to clear their faults For example in one embodiment the user issues a com mand from an input device coupled to the instrumentation control unit to clear faults If the mileage or other vehicle parameter e g engine hours etc is within predetermined limits such as below a predetermined mileage value the instrumentation control unit interprets the command as a 5 890 080 3 request to clear all faults throughout the vehicle The faults may be automatically cleared if the vehicle parameter preferably mileage is below a threshold value The instru mentation control unit broadcasts a message to the electronic control units on the data link instructing them to clear their faults This feature enables a technician to clear all faults easily from a central location No sophisticated diagnostic tools or special purpose software is necessary to reset a variety of devices on the data link Further features and advantages of the invention will become apparent with reference to the following detailed description and accompanying drawings BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 is a block diagram illustrating the system archi tecture in
51. uring the assembly process In this circumstance it is desirable to clear the events before delivery of the vehicle The ICU enables a user to clear faults and events in the data logging unit conveniently from the dash of the truck The data logging unit 180 generally includes memory 182 a microcontroller 184 an interface 186 to the data link a real time clock 188 and a power supply 190 The memory 182 and the real time clock are coupled to the microcon troller 184 via a bus 192 In this implementation the power supply includes a control chip that supplies power to the microcontroller from either the vehicle battery or a lithium battery The lithium battery serves as a back up in the event that the voltage supplied from the battery is insufficient or unavailable As noted above the data logging unit is coupled to the keypad 90 of the ICU FIG 2 to receive an interrupt when user actuates the event key on the keypad This connection is represented by the manual trigger switch 194 shown in FIG 6 The data logging unit can also receive interrupts from other devices as well memory 182 of the data includes both RAM 196 and ROM 198 This implementation includes 128 KB of ROM which stores the application code executed by the micro controller This executable code includes the set up routines 5 890 080 9 used to boot the data logging unit and the data logging routines used to monitor predefined events This implemen tation
52. use various bus structures known in the field of computer design may be used to interconnect the elements of the computer system in a number of ways as desired CPU 150 may be comprised of a discrete ALU 156 registers 158 and control unit 160 or may be a single device in which one or more of these parts of the CPU are integrated together such as in a microprocessor Moreover the number and arrangement of the elements of the computer system may be varied from what is shown and described in ways known in the art An external computer 140 such as a PC communicates with the data link 20 on board the truck through the data port 84 FIG 1 As noted above the data link 20 can be implemented according to the SAE standards J1708 J1587 In this case the external computer communicates with the ECUs on the data link according to the J1587 and J1708 protocols FIG 6 is block diagram illustrating the data logging unit in one embodiment of the invention The data logging unit monitors and records faults and events It is relevant to the method for resetting electronic control units on the data link because like the other ECUs on the data link it may need to be reset for example before delivery of the truck Events triggered in the data logging unit such as the manually triggered event from the keypad 90 of the ICU 32 may need to be cleared One significant example is when events pertaining to the data logging unit are inadvertently gener ated d
53. ving a plurality of installed electronic control units coupled to a serial communication link a 5 890 080 21 method for determining the installed electronic control units the method comprising from a instrumentation control unit located in a cab of the truck constructing a message including an instruction to respond with diagnostic data broadcasting the message on the data link from the instrumentation control unit monitoring the data link for diagnostic data broadcast by the installed electronic control units in response to the message from the instrumentation control unit receiving the diagnostic data broadcast by the installed electronic control units interpreting identity of the installed electronic control units on the data link from the diagnostic data compiling a list of the installed electronic control units storing the list of the installed electronic control units in memory of the instrumentation control unit comparing the list of installed electronic control units with an expected list to identify missing and unknown electronic control units on the data link and displaying information about the missing and unknown electronic control units on a display device coupled to the instrumentation control unit 10 A method for resetting electronic control units coupled to a data link in a truck wherein the electronic control units include an instrumentation control unit with a display device and an input device locate
54. whether the reset threshold has been satisfied includes determining whether the truck mileage is below the predetermined truck mileage 14 A method of claim 12 further including the step of displaying faults generated by the electronic control units in the truck in response to a first user request entered at a first electronic control unit and wherein the determining step is performed in response to second user request entered at the first electronic control unit 15 Amethod for resetting electronic control units coupled to a data link in a truck wherein the electronic control units include an instrumentation control unit with a display device and an input device located within a cab of the truck the method comprising in response to a user request to display diagnostic data entered at the input device displaying diagnostic data including a description of one or more faults from the electronic control units on the display device in response to a user request entered at the input device to clear a fault determining whether mileage is below a programmable value including reading the value of the mileage from the data link and comparing the value of the mileage with the programmable value if the mileage is below the programmable value then constructing a message instructing the electronic con trol units coupled to the data link to clear all of their faults and sending the message to the electronic control units over the da
55. y resetting faults that occur after the limited duration This ensures that fault and event data will not be corrupted and that it will be available for servicing the truck 10 15 20 30 35 45 50 55 65 18 In this embodiment the truck parameter either mileage or engine hours is a programmable parameter stored in a configuration file in the ICU s memory The value of the threshold can be established by setting its value in the configuration file One way to edit the configuration file is to download a new version of the configuration file to the ICU from an external computer connected to the data link via the data port Another way is to transfer a message to the ICU instructing it to update the field in the configuration file that stores the threshold value In the specific implementation shown in FIG 9 the programmable threshold value is represented by a parameter parameter 19 in the configuration file associated with diagnostic message screen 274 as shown in FIG 9 This parameter can be set at any integer value ranging from 0 to 255 This is only one specific example and the manner in which the programmable threshold is maintained in the ICU can vary clear the faults and events in this implementation the ICU broadcasts a message on the data link instructing the ECUS to clear their faults In this implementation the ICU constructs a message with PID 195 to instruct the ECUS to clear their faults T
Download Pdf Manuals
Related Search