ISOBUS Diagnostics, Spring 2004

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 dont 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..
• gt All bets are off
• gt Be careful about assumptions
• You want to know which ecus 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
• J1939-73 ISO 15765

4 Parts, in Draft ? std pgns DPP Spns?
-gt Standardized ? --- Prop ?
Published 1996, 98, 01 19 std pgns 2 in
Draft Spns -gt 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
  Mfrs, (except for emissions related) but caution
  is recommended. See J1939-73

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

• 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

• 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

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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)

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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

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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?
• ??

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What is good about this?

• (Remote Troubleshooting) - If the problem can be
  known diagnosed before the technician even
  drives out of the service center, wouldnt 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 spnsdirectly associated with each user.
• I.e. a 10 column by 345 row matrix (so far)

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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 gt 345 data points

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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.

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• 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 ..?

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• 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
  Addresss, 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/j193
  9.htm

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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