HEARING IS A FASCINATING SENSATION

ArtemiS SUITE

Decoder for CAN, FlexRay and GPS Decoding information from the digital

bus systems CAN and FlexRay as well as from GPS data

ArtemiS SUITE – Decoder 2

Decoder

Motivation

CAN and FlexRay are field bus systems, used for linking the steadily growing number of control devices in vehicles. In the field of NVH, bus systems are often used to record, e.g., the engine RPM, the vehicle speed or the throttle position with minimal expense.

When recording CAN and FlexRay signals, the HEAD acoustics hardware and software saves an encoded channel per data bus, which generally contains a multitude of different signals. The decoder allows you to extract the required data, and to file these data as additional analog channels along with the original data.

The described functionality of the Decoder can be found in ArtemiS SUITE from Version 6 onward, with ArtemiS SUITE Module ASM24 (Data Preparation).

ArtemiS SUITE – Decoder 3

Decoder

Motivation

In addition to the analog data, GPS data can be recorded by means of many HEAD acoustics front ends (SQobold, SQuadriga II, HEADlab). The vehicle speed is an important parameter for NVH applications. It is extracted from the GPS data and is often used as reference value for further analyses.

Moreover, a GPS track can be determined from the positioning data. The covered track is saved in a separate file. The track can be displayed in a map view by means of appropriate programs (e.g., Google Earth®).

The described functionality of the Decoder can be found in ArtemiS SUITE from Version 7 onward, with ArtemiS SUITE Module ASM24 (Data Preparation)

ArtemiS SUITE – Decoder 4

Decoder

In ArtemiS SUITE, the Decoder is provided as a project. It is opened via New -> Decoder Project, or in the context menu in the HEAD Navigator via Open with -> Decoder Project.

The Decoder Project is structured like a Pool Project. There are corresponding fields for recordings, the decoding instructions and the export format for the files with the extracted channels.

In the bottom field of the user interface there is a preview window showing the history of the decoded values for an adjustable length of the recording.

ArtemiS SUITE – Decoder 5

Decoder

Recordings can be inserted from the HEAD Navigator via Drag&Drop. Alternatively, the standard file selection dialog may be used.

In most cases, the selected export format is HDF Export, so that the generated files can be processed in ArtemiS SUITE without difficulties.

The file export is configured via the Properties, and adapted to your requirements regarding target directory and file name.

ArtemiS SUITE – Decoder 6

Decoder – Decoding a CAN Data Stream

In order to decode the CAN data stream from your recording and extract single values, a decoding instruction must first be defined in the center field. This is always based on a vehicle-specific dbc file, valid for this CAN bus.

Open a dialog via Insert CAN Decoder to select both the appropriate dbc file and its values to be extracted.

In the example, OBD-2 information has been filed in the CAN channel. In order to decode OBD-2, an OBD Decoder is to be selected, which automaticlly provides the OBD.dbc.

ArtemiS SUITE – Decoder 7

Decoder – Decoding a CAN Data Stream

The Decoder automatically checks whether all inserted recordings contain the selected CAN information. This is confirmed by green status indicators. If the selected information is not present, this is indicated by a warning.

The entries of the decoding instruction can be expanded, and then configured.

Both the names and the units of the channels with the extracted data can be determined. Selecting a suitable interpolation allows for smoothing the curves, which are directly shown in the preview.

ArtemiS SUITE – Decoder 8

Decoder – Decoding a FlexRay Data Stream

In comparison to CAN, FlexRay bus systems provide a considerably higher data transmission rate and system stability, as these are, e.g., requirements for driver-assistance systems.

The decoding of FlexRay channels in ArtemiS SUITE is analogous to the decoding of CAN. Instead of a dbc file, however, an XML-based Fibex file is required, which contains the descripition of the bus system.

Tire speed RR

Tire speed RL

Tire speed RR Tire speed RL

Tire speed FR

Tire speed FL

Tire speed RR

Tire speed RL

ArtemiS SUITE – Decoder 9

Decoder – Decoding a FlexRay Data Stream

Open a dialog via Insert FlexRay Decoder to select both the appropriate Fibex file and its values to be extracted.

Due to the high data rates on the FlexRay bus, the data stream might not be recorded completely. Therefore, the selection dialog indicates whether the information of the Fibex file is found in the FlexRay channel of the recording.

Tire speed RR

Tire speed RL

Tire speed RR Tire speed RL

Tire speed FR

Tire speed FL

Tire speed RR

Tire speed RL

ArtemiS SUITE – Decoder 10

Decoder – Decoding a GPS Data Stream

Measurements containing a GPS channel can be decoded by means of a GPS Decoder.

Parameters like speed and altitude as well as the degrees of longitude and lattitude can be extracted and saved with selectable units.

Delays between GPS and analog data can be compensated. Typical, system-inherent delays are offered for the GPS receiver actually used, or can be entered numerically.

ArtemiS SUITE – Decoder 11

Decoder – Decoding a GPS Data Stream

The covered track can be exported as separate GPX or KML file via the GPS Track Decoder.

The files can be displayed as a track in the map view of Google Earth®. The position on the traveled distance can be calculated for any point of time by analyzing the time.

Thus, the GPS track allows to analyze in a reliable way any position of the covered track, where certain sound phenomena occur, e.g., brake sounds on sustained steep inclines.

ArtemiS SUITE – Decoder 12

Decoder

During the decoding process, a new file is generated by the Decoder in ArtemiS SUITE. It not only contains the encoded CAN, FlexRay or GPS channel, but also the selected CAN, FlexRay or GPS information as separate channels.

If a measurement contains e.g., CAN and GPS channels, the information of both

channels can be decoded in the Decoder Project in one step.

The channels which have been generated by means of the Decoder can then be used e.g., as reference values for continued analyses.

Further information regarding CAN and OBD-2 can be found in the Application Notes „Recording and Evaluating CAN-Signals“ and „Recording OBD-2 information“.

The Application Notes can be found in the Download Center of our website, or on the ArtemiS SUITE start page under the slider Online.

Thilo Leitmann, Vertrieb NVH thilo.leitmann@head-acoustics.de

www.head-acoustics.de © Copyright HEAD acoustics GmbH