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One of the major tasks of ECU development is the calibration and test of control strategies, i.e. tuning of parameters and the recording of internal variables during the runtime of the ECU. This These tasks can be done via various busses, bus protocols or proprietary plug-on devices between the ECU and the calibration system. Those interfaces are technology-dependent and vendor-specific. In order to provide uniform access to an ECU, calibration tools typically have an MC-server that other tools can use to connect to an ECU without having to deal with different interface technologies. The main objective of the ASAM MCD-3 MC standard is to specify the functions of an MC-server and to provide a remote control interface for client applications to the MC-server via an object-oriented API. The functions of an MC-server are primarily to provide measurement and calibration services to clients. The standard allows that any client application, such as test automation systems or automated calibration systems, can connect via the MC-server to an ECU and carry out typical measurement and calibration tasks. Several client applications can be connected to one MC-server and have access to one ECU in parallel. 

To be able to access data on an ECU, the MC-server reads an A2L data description file (according to ASAM MCD-2 MC), which contains a description of available calibration parameters (CHARACTERISTICS) and measurement variables (MEASUREMENTS).  The MC-server then makes services available to access this data. Methods for read- and write-access to the calibration parameters of various types such as scalars, arrays, strings and look-up tables can be used. Measurement access methods are available via Collector, Watcher and Recorder services. The Collector acquires the values of measurement variables or calibration parameters with a common rate over a defined period of time (continuous data acquisition) and sends the data to the client applications at the same time. The Recorder is used to manage high bandwidth measurements, when synchronous data transfer to the client is not possible. The Recorder stores the data locally and makes it available to clients at a later time. A Watcher is a service which continuously monitors measurement variables or calibration parameters and triggers events if a predefined condition is met. Multiple Watchers can be defined to monitor multiple objects at the same time. The Watcher may be used to start and stop Collectors or Recorders.

The standard is used for calibration and measurement purposes in development, testing and production of ECUs. ASAM MCD-3 MC currently coexists with the older ASAM ASAP3 standard, which is dependent on specific interfaces (RS232, Ethernet) and is still widely used. The ASAM MCD-3 MC API is specified in an object-oriented but technology-independent UML model and mapped to DCOM. This configuration allows to easily add new addition of new programming language mappings to the standard without having to change the core of the standard.

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TitleApplication Programming Interface for Measurement and Calibration Server
CategoryAE

Current Version

3.0.0
Release Date23.09.2011
DownloadASAM MCD-3 MC V3.0.0
Application Areas
  • Test stand automation

  • Automated calibration

  • Data logging

Specification Content

  • Client-server API
  • Technology references for COM-IDL
  • MC-server architecture

File Formats

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ASAM MCD-3 MC started life in the early 90th 1990s as a company-specific specification from AVL List that defines a serial interface protocol based upon RS232 for test stand automation systems. The specification was used as the foundation to create the first public standard under the name ASAP3. In subsequent years, the standard was further developed and TCP/IP was added as a second supported protocol.

By the end of the 90th, ASAP3 got transferred 1990s, ASAP3 was given to ASAM and renamed to ASAM MCD-3. The members of ASAM created new strategic guidelines for further developing the standard. The standard was lifted was promoted to a higher level, now describing a hardware-independent software interface rather than a hardware-dependent protocol. The drafts of the two specifications ASAM MCD-3 D and ASAM MCD-3 MC have been merged into one standard. Data and functions were described via object-oriented models. The new standard supported significantly more use-cases for test stand automation and automated calibration than before. A library implementation from Vector Informatik was used as the template for the first version of this fundamental re-design of the standard. The standard got released in standard was released as version 1.0 by 0 in 2003. The standard was further matured and revised with the help of prototype implementations and cross-testing events.

For version With version 2.0 and 2.1, the Watcher- and Recorder-services have been added. Since the requirements for the MC part and the diagnostics part of the standard increasingly diverged, ASAM decided to split the standard into two independent standards. Since version 3.0, the name of the standard is now ASAM MCD-3 MC. This version improves the initialization-time of MC-servers and the connection and release of client application.

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Motivation

The main motivation for ASAM MCD-3 MC and its predecessors is to provide standardized and abstracted access to ECU calibration parameters and measurement data. The standard uses calibration tools for this purpose, which have direct access to such data. The standard adds a server module to calibration tools with a specified software interface. The interface completely decouples client applications from hardware-, bus-, protocol- or vendor-specific properties of subsequent components of the tool chain.

Since the MC-server is implemented as a software interface, it is  the server interface is directly available in programming languages and scripts that can be written by end users. MC-servers according to this standard provide ECU data in their physical representation format, i.e. 50km/h instead of 0x3C. This has the advantage that programs for test automation or automated calibration are independent from the ECU software. They can be easily ported to different ECUs and different tools. 

Application Areas

The primary application area from the beginnings of the standard until today is area is test stand automation. The execution of tests for ECUs, vehicle components such as subcomponents, engines and complete vehicles is mostly automated in today's test labs. Tool setup, configuration, programming and debugging could consume a significant portion of the available time for testing and the utilization of expensive test stands. ASAM MCD-3 MC is one provision to significantly reduce this time.

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ASAM MCD-3 MC is the successor of ASAM ASAP3. Both standards are not compatible to each other, though. They just The two standards just cover broadly the same application areas and use-cases.

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From a technical point-of-view, ASAM MCD-3 MC is a modern standard that covers a wide array of use-cases for MC-servers. Despite its sophistication, ASAM MCD-3 MC has never been that been more successful in the industry than its early predecessor ASAM ASAP3. The level of sophistication and covering the attempt to cover many use-cases resulted in a complex API, which is costly in implementation and complex in use. The forced integration of D-servers to the standard throughout its development history contributed to the complex API. The D-server has been separated from the standard meanwhile, but the complexity of the API remained essentially the same. Furthermore, the standard favors an implementation via DCOM, whose configuration and administration is considerably more complex compared to ASAP3-based systems. Since ASAP3 covers the most important use-cases, is easier to use and is very stable in operation, there has been rarely a good reason  there is rarely justification to switch to ASAM MCD-3 MC. Although version 3.0 of the standard was released in 2011, most tool vendors stick with the version vendors still use version 2.2 implementation in their tools until today.

List of Deliverables

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