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Understanding CAN DBC

CAN DBC refers to database CAN. In simple terms, the type of data that communicates over a CAN bus can be read and understood using DBC files. DBC is an ASCII based translation, a standard file evolved in the 1990s. Now being used by the automotive industries worldwide. These files can help identify the data within the CAN frame by describing it. As these CAN database, text files contain information for decoding raw CAN bus to physical values. Thus, functioning as a signal library.

For a DBC file, the signal is not an electrical input or output, but it is a physical parameter, such as temperature, engine speed, voltages etc. DBC is the most common way to handle the identification and translation of 8-byte hexadecimal CAN message and raw CAN data. The data in a CAN frame can be broken up into eight one-byte values, sixty-four one-bit values, one sixty-four bit value, or any combination of these. The data field can contain up to 8 bytes of data. A single CAN frame can contain 0 to 64 individual signals (for 64 channels, they would all be binary).

The DBC file contains the following information.

  • The CAN ID of the message in which this signal is present

  • The position where the signal is present in the CAN message

  • The byte order of the signal

  • The conversion details of the signal

  • Unit of the signal

Now let us try to understand this in detail, with the help of an example using Influx Dialog Software

Engine RPM Signal in Message named ECU defined in a DBC.

Message Definition:

The message definition contains the following information:

  • CAN ID: