CAN Frame Properties

The following properties are available on the Frame Properties page if the database cluster is configured to use the CAN protocol.

  • Name—Name of the frame. This must be unique within the cluster.
  • Arbitration ID—CAN frame identifier. This ID is used to determine priority during arbitration. In the standard frame format the length of the ID is 11 bits. The extended frame format has two fields, which are 11 bits and 18 bits in length. Select 29-Bit ID for the extended frame format.
  • 29-Bit ID—Enable Arbitration ID to use extended frame format.
  • Payload Length—Number of data bytes that can be transmitted in the frame's payload. The payload length for CAN is 0–8 bytes. CAN FD allows values of 12, 16, 20, 24, 32, 48, and 64.
  • Timing Type—Specifies the CAN frame timing: Cyclic Data, Event Data, Cyclic Remote, Event Remote, or Event/Cyclic. For detailed information, refer to CAN: Timing Type in NI-XNET API References or Cyclic and Event Timing in the NI-XNET User Manual.
  • I/O Mode—Specifies the CAN standard to be used. You can specify an option only in CAN FD + BRS mode, which enables you to configure each frame to be transmitted in any of the three options.
  • CAN—CAN 2.0 standard, with a payload length of 0–8 bytes.
  • CAN FD—CAN Flexible Data-Rate, which allows extended frame format and a payload length up to 64 bytes.
  • CAN FD + BRS—CAN FD with Baud Rate Switch, which enables the CAN frame to be transmitted at the standard data rate or the faster CAN FD rate.
  • Transmit Time—Frame rate for cyclic types; the debounce time for event frames.
  • Mapped PDUs—Any PDU(s) mapped to this frame. Displays the PDU name, the start bit of the PDU inside the frame, and the update bit for the PDU inside the frame.
  • Bit Layout—Visual element depicting the signals contained within this frame and the byte order of each signal. Beneath the bit layout on the Frame Properties page, you can select Show as PDUs to show the PDU(s) mapped to this frame.
  • Comment—Note or descriptive text related to this frame. The comment is used for information only.

    • The following properties are available in the J1939 Configuration panel of the Frame Properties page if the database cluster is configured to use the SAE J1939 application protocol with CAN.

  • J1939 PGN—Parameter Group Number (PGN), which identifies the frame and defines which signals it contains.
  • Reserved (EDP)—Specifies an Extended Data Page bit value of zero. In combination with Data Page, functions as a page selector for PDU Format.
  • Data Page—Specifies a Data Page bit value of zero. In combination with Reserved (EDP), functions as a page selector for PDU Format.
  • PDU Format—Defines whether the frame is to be transmitted with a destination address or broadcast to the entire network.
  • PDU Specific—If PDU Format is between 0 and 239, PDU Specific is interpreted as the destination address (PDU1). If PDU Format is 240 or greater, then the frame intended for all devices and PDU Specific is interpreted as a Group Extension (PDU2).
  • Priority—Priority value of the frame, used when multiple CAN frames are sent on the bus at exactly the same time. Lower numbers have higher priority.
  • Source Address—Address of the node transmitting the frame.