Addressing of Control Units for Diagnosis Purposes
Publication Date: 2004-Apr-07
The IP.com Prior Art Database
In order to both fulfill the legal regulations regarding the communication between a vehicle and an external test equipment for emissions-related diagnostics and to enable a consistent means of diagnosing various kinds of ECU:s in a vehicle, also if these units are attached to a sub-network, fixed normal addressing format is used to identify all units, which belong to a network in the vehicle that is delivered and/or assembled by a particular supplier/manufacturer. Mixed addressing format is used to identify units that are provided and installed by other suppliers/manufacturers. Thereby, the primary manufacturer may address all its internal control units in accordance with the relevant standards. At the same time, the primary manufacturer is provided with a standardized addressing interface towards any external control units.
Control Units for Diagnosis Purposes
In order to increase the efficiency and flexibility, the automotive industry has developed towards an increased use of network solutions for controlling various kinds of units and processes in the vehicles. For instance, the Controller Area Network (CAN) standard specifies a widely used means of accomplishing such a network in trucks, busses and other vehicles. Moreover, a diagnostic protocol called Keyword 2000 renders it possible to interconnect different electronic control units (ECU:s) to form a network (a Keyword 2000 network). This type of network, in turn, may include one or more sub-networks. Each such sub-network is connected to the main network via an ECU, which has an interface both towards the main network and towards the sub-network in question.
Keyword 2000 also allows two different identifiers to address an ECU in a CAN, namely a fixed normal addressing and a mixed addressing. Fixed normal addressing represents the standard address format in a single network, whereas mixed addressing is used when performing diagnostic testing of control units within a sub-network.
So-called On-Board Diagnostic (OBD) systems may be used to perform tests whether a specific control unit connected to a CAN is operating properly. An on-board diagnostic facility, such as a dashboard mounted display, may provide access to information generated by the OBD system.
Although, according to Keyword 2000, it is technically possible to carry out a diagnostic testing of all control units which are connected to the above-mentioned main- and sub-networks using fixed normal and mixed addressing, this is not permitted according to the legal regulations regarding the communication between vehicle and an external test equipment for emissions-related diagnostics. Namely, these regulations prescribe that only fixed normal addressing be used.
Therefore, in order to both fulfill these regulations and to enable a consistent means of diagnosing various kinds of ECU:s in a vehicle, even if these units are attached to a sub-network, it is proposed that fixed normal addressing format be used to identify all units, which belong to a network in the vehicle that is delivered and/or assembled by a particular supplier/manufacturer, and that the mixed addressing format only be used to identify units that are provided and installed by other suppliers/manufacturers.
Consequently, all ECU:s developed and installed by a primary manufacturer, say Scania, Volvo, DaimlerChrysler, Iveco, Hino etc, are addressed by using fixed normal addres...