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ISOBUS Diagnostics, Spring 2004

ISOBUS Diagnostics, Spring 2004. A presentation to the North American ISOBUS Implementation Task Force (NAIITF) Keith Hudson & the NAIITF Diagnostic Discussion Group May 2004. Diagnostics “Vision” The Seven Dimensional Matrix. Consider the following:

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ISOBUS Diagnostics, Spring 2004

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  1. ISOBUS Diagnostics, Spring 2004 A presentation to the North American ISOBUS Implementation Task Force (NAIITF) Keith Hudson & the NAIITF Diagnostic Discussion Group May 2004

  2. Diagnostics “Vision”The Seven Dimensional Matrix Consider the following: • All the ISOBUS involved countries of the world • All the ISOBUS companies of the world • All Tractors & other Ag/Forestry Vehicle Models….. • All the Model years..… • All the Vehicle/Implement combinations • All types of ecus used on the ISOBUS • All of the customers….with problems…& with telephones…..

  3. Overall Quantity of problems? • A factorial that I don’t even want to calculate…. • A potentially large amount of unique design & diagnostic information to store • Also, phone calls, machine downtime, & diagnostic time • So, how simple can we make this?

  4. My machine is broken …what should I do? • Diagnostics – Something is WRONG.. • => All bets are off • => Be careful about assumptions • You want to know which ecu’s are on the ISOBUS & what the fault messages are…. • How do we do that?

  5. Typical network management • Address Claim NAME/Source Address Table • Diagnostics: ISO 11783, Part 12 • J1939-73ISO 15765 4 Parts, in Draft ? std pgns & DPP Spns? -> Standardized ? --- Prop ? Published 1996, 98, 01 19 std pgns + 2 in Draft Spns -> J1939 stdzd --- PspnR

  6. ISO 11783, Part 12ISOBUS Diagnostics Checkoff Sheetsfor section 5.3.1, Implement Network Summary,What info do I need? • J1939-73 checkoff sheet • ISO 15765 checkoff sheet

  7. J1939-73, DM1 message breakdown pgn # 65226 • Active Faults • The DM1 message has several parts: • Status indicators for lamps (4) • SPN - Suspect Parameter Number (19 bit number assigned by J1939) • FMI – Failure Mode Identifier (5 bit number, 0 to 31 states that define the failure mode) • SPN Conversion Method • Occurrence Count

  8. Suspect Parameter Number (SPN) • This is a 19 bit number that can have a value from 0 to 524287 • Most of this range is assigned by SAE J1939 committee (range of 0 to 520191) • Currently, they have assigned up to ~3,200 spn numbers • The range of 520192 to 524287 is considered the Manfacturer Specific or “Proprietary spn Range” (PspnR) • Generally, this range can be assigned used by Mfr’s, (except for emissions related) but caution is recommended. See J1939-73

  9. J1939-73A Diagnostic Trouble Code (DTC) as used in a DM1 pgn

  10. DM1 – Active Faults DM2 – Prev. Active Faults DM3 – Clear Prev. Active DM4 – Freeze Frame DM5 – Diag. Readiness DM6 – Cont. Mon. Tests DM7 – Command CMTests DM8 – Results Non CMS DM9 – Oxygen Sensor DM10- Non CMS Support DM11 – Active Faults DM12 – Emissions Active DM13 – Stop/Start Broad. DM14 – Memory Acc. Req DM15 – Memory Acc. Resp DM16 – Binary Data Trans DM17 – Boot Load Data DM18 – Data Security DM19 – Calibration DM20 – Mon. Perf. Ratio DM21 – Diag. Readiness 2 J1939-73 pgns

  11. 64 bit NAME information • Manufacturer ID - An 11 bit number that identifies the Mfr of an ecu • Currently 150 Mfrs + 15 NMEA Mfrs. • NickNAME - An acronym that uniquely defines the Function of the ecu, as found in the “B” Tables. • 3 fields used: Industry Group, Device Class, & Function • Example: 2-6-128 • Industry Group 2 - Ag • Device Class 6 - Sprayers • Function 128 - Spray Rate Control • Identity Number – A unique 21 bit number used by the Mfr.

  12. J1939 Diagnostics – Active Fault Message(s) 65226 Table Mfr ID NickNAME Ident Nmbr NAME DM1 (64 bit) SA (8 bit) DTC SA SPN (19 bit) J1939 Top Level App., ~3,200 standard spns assigned at this time + FMI (5 bit) J1939-73 App. A table, 0 to 31 states

  13. What is broken? • DTC = 1542.5 • Spn # = 1542 (ECU PS Voltage #2) • Fmi # = 5 (Current below normal or open ckt)

  14. So what do you know now?J1939-73 Checkoff sheet • 64 bit NAME • Ag Sprayer ecu - (NickNAME, 2-6-128) • Mfr id - (165 mfrs so far listed) • Identity number - (21 bit number) • DM1 message - (at least one DTC) • Spn (Mfr. Proprietary or SAE public?) - ECU supply voltage #2 • Fmi - open ckt

  15. So what do you know now?ISO 15765 Checkoff sheet • 64 bit NAME • Ag Sprayer ecu - (NickNAME, 2-6-128) • Mfr id - (165 mfrs so far listed) • Identity number - (21 bit number) • DM1 message? - (at least one DTC) • Some kind of Health message? • ??

  16. What is good about this? • (Remote Troubleshooting) - If the problem can be known & diagnosed before the technician even drives out of the service center, wouldn’t that be handy? • If you had a better idea which replacement parts to put in the truck, or if you could walk right up to the problem area when you are there, would that reduce downtime?

  17. Why Standardize ? • One thing that needs to be kept in mind: • If you support 2, 5, or 10 customer/users this could be problematic. • If they all want their own definitions for say…..345 spns, then you have to keep a dB of 3,450 spns…directly associated with each user. • I.e. a 10 column by 345 row matrix (so far…)

  18. 80/20 rule • Suppose you could standardize 80% of those spns? • Then you have 276 rows that could be used by all 10 columns of users. (276 data points) • And 69 rows/10 columns to have to juggle proprietarily (690 Proprietary data points) • Grand Total of 966 spns data points to manage, vs. 3,450 (so far…..) • IF 100 % standardized => 345 data points…

  19. Basic CAN requirements • A compliant device should have a 64 bit NAME & an 8 bit Source Address, and successfully completed the Address Claim process. • This can be checked with a Request for Address Claim.

  20. Now, assuming an ISO Part 12 compliant device & that it at least can still communicate • An ecu with a fault should be broadcasting some kind of “Active Faults” diagnostic message • If a J1939-73 device, this would be the “DM1” message, (pgn # 65226). • If an ISO 15765 device, this would be the ………..?

  21. When all of the ecus (on the particular bus that you are on) have responded, your Diagnostic device now can have a NAME/Source Address table. • This can give you quite a bit of information about the ecu.

  22. To “find” J1939 on the SAE site… • Truck & Bus Electrical / Electronic Standards Committee and Subcommittees - Public Forum • http://forums.sae.org/access/dispatch.cgi/TETEpf Listed in the document area below is: • NEW J1939 Request Form and Guidelines (May03) • This is a folder with 2 documents in it • SAE J1939 Request form R1.3.doc • use for making all J1939/ISO 11783 requests • J1939 Truck and Bus Request Processing Guidelines - R3.0.doc • use to learn how to contact J1939 & interact with the committee • Example: Manufacturer id, PGNs, Parameters, Functions for 64 bit NAMES, 8 bit Source Address’s, Diagnostic spns, etc. These are also known as the “B tables”, as part of the Top level Appendix

  23. Questions? • SAE J1939 Standards Collection • http://www.sae.org/standardsdev/groundvehicle/j1939.htm

  24. Device Class Common Messages (DCCM) • Would we like to all use the same messages for the common Implement Bus Functions? • For each Device Class, can we agree on at least 5 pgns that would handle 80% of the needed functionality? • Device Classes - Sprayers, Seeders, Spreaders, Harvesters, etc

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