Source Address Auto-detection源地址的自检测

Other RestrictionsTC10 applications may only use selections with 81% sample points as recommended by J1939.A.3.5.3.J1939-BASED SHIFT SELECTORS Shift selector communication must be directed to a specific CAN port.[19020] SHIFT SELECTORS: J1939-Based Selector Connection—CAN1 (1)—CAN2(1)Default answer.Other RestrictionsThe selected CAN port ON-VEHICLE PROTOCOL must be set to one of the SAE J1939 options.Customer-supplied selectors using public J1939 data may only be connected to a CAN port where whose ON-VEHICLE PROTOCOL=SAE J1939 FULL FUNCTIONALITY.When dual J1939-based shift selectors are used, both must connect to the same TCM CAN port.A.3.5.4.DIAGNOSTIC COMMUNICATIONThe VEPS / ACCT options below set the diagnostic protocol and CAN port for reading and clearing DTCs with non-Allison tools. They do not impact Allison DOC®communication.Also, regardless of the options selected below, J1939 DM1 broadcast is supported on the CAN port set to SAE J1939 FULL FUNCTIONALITY. See DIAGNOSTIC COMMUNICATION FOR OEM USE for further details.[18070] DIAGNOSTICS: Protocol—SAE J1939-73—UDS WITH SAE J2012 DTC FORMAT(1)—SSF14230 WITH SAE J2012 DTC FORMAT[18080] DIAGNOSTICS: J1939-73 Connection —CAN1 (1)—CAN2—CAN3(1)Default answer.Other RestrictionsWhen SAE J1939-73diagnostics are to be used, [18080] DIAGNOSTICS: J1939-73 Connection must specify a CAN port that uses a compatible ON-VEHICLE PROTOCOL(i.e. set to one of the J1939 answers, or NONE). A.3.6.AUTO-DETECTIONAuto-detection reduces the number of customer modifiable parameters that the vehicle OEM must set. When the TCM is powered up after a vehicle is assembled, auto-detection logic looks for various input sources and locks onto the most preferred of those available for a given input.A.3.6.1.1.Source Address (SA) DetectionProcessMessages, Parameters and SAs ImpactedWhere applicable, the J1939-based functions in this document list the acceptable multiplexed source addresses and their order of TCM preference. TimingUnless the OEM specifies an SA through VEPS (where available), the TCM looks for the most-preferred source address for approximately 50 engine start cycles.SA Selection during Auto-Detect PeriodDuring the SA auto-detect period, the TCM looks for multiplex-capable parameters from their calibrated lists of acceptable source addresses.When a“more preferred”source is found for a given multiplexed parameter, the TCM will lock onto that source and ignore parameter instances coming from“less preferred”sources.For example, if on the first key switch cycle the parameter CCVS1Brake Switch is found coming from SA 00--and only SA 00--the TCM will use this parameter source. If, during a subsequent cycle within the SA auto-detect window, the CCVS1 Brake Switch is found coming from both SA 00 and SA33, the TCM will lock onto SA 33 as the source, as it is higher in terms of calibrated source preference,per the SERVICE BRAKE STATUS function.If the most preferred source is found for a given parameter, the auto-detect process for that parameter is stopped immediately, and all lesser sources are ignored for that parameter.While the auto-detect process ignores parameters indicating“Not Available”, parameters indicating “Error”are included. Per SAE J1939,“Error”indicates that the broadcasting controller supports the parameter, but a temporary problem prevents a correct value from being broadcast.When the SA auto-detect process is complete,the SA for each multiplexed parameter is locked in to the most preferred source seen during the auto-detect period.A.3.6.1.2.Parameter EchoingEchoing occurs when a parameter is sent out by one controller,received by another, and then re-broadcast in a second message instance. The source address most likely to echo a parameter is the source address that traditionally broadcast that parameter before a multiplexed system was implemented.Per SAE J1939,parameter broadcasts should originate from the controller that receives or generates the physical input. For example, the controller connected to the accelerator pedal sensor input should likely be the one to broadcast EEC2 Accelerator Pedal Position 1.Echoing is not recommended because:—Echoed data may involve a time lag that could affect closed loop control in the vehicle system.—Different network devices may utilize the same parameter from different sources, leading to interaction problems.—Echoed parameters may not reflect all of the diagnostic capability of the originating device.A.3.6.1.3.Failure Modes and Responses Most source address detection problems stem from:—vehicle controllers broadcasting inappropriate data (Error or Not Available),—devices not connected to the J1939 network before the auto-detect process completes, or—Devices whose source address is changed via a service tool either during or after completion of the auto-detect process.In any case, a source may be incorrectly detected, and functions may not operate as desired.A.3.7.J1939 NETWORKMANAGEMENTAll Allison 5th Generation TCMs and shift selectors support the J1939 address claim message.All Allison 5th Generation components utilize fixed addressing, as is reflected in their address claims broadcast at power-up and on request. Source addresses used by the TCM are not alterable, while the source addresses(SA 05 and SA 06) used by Allison shift selectors are configured via a jumper wire.。