ndOBDOpenOnCANFD

Purpose

Opens a diagnostic session on a CAN or CAN FD port for OBD-II.

Format

        long ndOBDOpenOnCANFD (
       char CANInterface[],
       unsigned long long baudrate,
       unsigned long long FDbaudrate,
       unsigned short ioMode,
       unsigned short maxDLC,
       unsigned long transmitID,
       unsigned long receiveID,
       TD1 *diagRefOut);
      

Input

CANInterface

Specifies the CAN interface on which the diagnostic communication should take place.

NI-CAN

The CAN interface is the name of the NI-CAN Network Interface Object to configure. This name uses the syntax CANx, where x is a decimal number starting at 0 that indicates the CAN network interface (CAN0, CAN1, up to CAN63). CAN network interface names are associated with physical CAN ports using Measurement and Automation Explorer (MAX).

NI-XNET

CompactRIO or R Series

If using CompactRIO or R Series hardware, you must provide a bitfile that handles the CAN communication between the host system and FPGA. To access the CAN module on the FPGA, you must specify the bitfile name after the @ (for example, CAN1@MyBitfile.lvbitx). To specify a special RIO target, you can specify that target by its name followed by the bitfile name (for example, CAN1@RIO1,MyBitfile.lvbitx). RIO1 defines the RIO target name as defined in your LabVIEW Project definition. The lvbitx filename represents the filename and location of the bitfile on the host if using RIO or on a CompactRIO target. This implies that you must download the bitfile to the CompactRIO target before you can run your application. You may specify an absolute path or a path relative to the root of your target for the bitfile.

baudrate

The diagnostic communication baud rate. You can wire standard baud rates as well as custom 64-bit baud rates to this control. For more information on 64-bit nonstandard baud rates, refer to the NI-XNET Hardware and Software Help. You can use the NI-XNET Bus Monitor and NI-XNET Database Editor utilities to create a custom baud rate. Refer to NI-XNET Tools and Utilities Help and NI-XNET Hardware and Software Help for more information about creating custom baud rates.

FDbaudrate

The diagnostic communication CAN FD baud rate for use with the CAN FD+BRS ioMode. You can wire standard FD baud rates as well as custom 64-bit baud rates to this control. For more information on 64-bit nonstandard FD baud rates, refer to the NI-XNET Hardware and Software Help. You can use the NI-XNET Bus Monitor and NI-XNET Database Editor utilities to create a custom FD baud rate. Refer to NI-XNET Tools and Utilities Help and NI-XNET Hardware and Software Help for more information about creating a custom FD baud rate.

ioMode

The CAN I/O mode used for diagnostic communication. Choices are:

maxDLC

The maximum CAN frame length to be used in CAN FD diagnostic communication. Allowed values are 8, 12, 16, 20, 24, 32, 48, and 64. For an ioMode of CAN 2.0, this setting is ignored and a value of 8 is used. For the CAN FD settings of the ioMode, this limits the frame size for transmission of diagnostic requests. The receive data length is determined from the incoming messages and not limited by this value.

transmitID

The CAN identifier for sending diagnostic request messages from the host to the ECU. Set to –1 (0xFFFFFFFF) for the default OBD CAN identifier.

receiveID

The CAN identifier for sending diagnostic response messages from the ECU to the host. Set to –1 (0xFFFFFFFF) for the default OBD CAN identifier. Output

diagRefOut

A struct containing all necessary information about the diagnostic session. This is passed as a handle to all subsequent diagnostic functions, and you must close it using ndCloseDiagnostic.

Return Value

The return value indicates the function call status as a signed 32-bit integer. Zero means the function executed successfully. A negative value specifies an error, which means the function did not perform the expected behavior. A positive value specifies a warning, which means the function performed as expected, but a condition arose that may require attention.

Use the ndStatusToString function to obtain a descriptive string for the return value.

ndOBDOpenOnCANFD opens a diagnostic communication channel to an ECU for OBD-II. The CAN port specified as input is initialized, and a handle to it is stored (among other internal data) into the diagRefOut struct, which serves as reference for further diagnostic functions.

If the transmitID and receiveID parameters are set to –1, communication is first tried on the default 11-bit OBD CAN identifiers; if that fails, the default 29-bit OBD CAN identifiers are tried. If that also fails, an error is returned.

If valid transmitID or receiveID parameters (11-bit or 29-bit with bit 29 set) are given, communication is tried on these identifiers. If that fails, an error is returned.

In general, it is not necessary to manipulate the diagRefOut struct contents.

Possible examples of selections for the interface parameter for the various hardware targets are as follows.

Using NI-CAN hardware:

• CAN0—uses CAN interface 0.
• CAN1—uses CAN interface 1 and so on with the form CANx.
• CAN256—uses virtual NI-CAN interface 256.

Using NI-XNET hardware with NI-XNET Frame Input/Output-based sessions:

• CAN1@nixnet—uses CAN interface 1 of an NI-XNET device.
• CAN2@nixnet—uses CAN interface 2 of an NI-XNET device and so on with the form CANx.

Using NI-XNET hardware with NI-XNET Stream Input/Output-based sessions:

• CAN1@ni_genie_nixnet—uses CAN interface 1 of an NI-XNET device.
• CAN2@ni_genie_nixnet—uses CAN interface 2 of an NI-XNET device and so on with the form CANx.

Using R Series:

• CAN1@RIO1, c:\temp\MyFpgaBitfile.lvbitx—uses a named target RIO1 as compiled into the bitfile at location c:\temp\MyFpgaBitfile.lvbitx.

Using CompactRIO:

• CAN1@/MyFpgaBitfile.lvbitx—uses compiled bitfile MyFpgaBitfile.lvbitx, which must be FTP copied to the root of the CompactRIO target.