OBD Blocks

OBD compliance is a major challenge for automakers and suppliers. At a minimum, correct interpretation of the regulation into technical requirements is difficult, the regulation drives hardware design from the project’s commencement, and implementation of the OBD software regularly amounts to about half the code for engine-control applications. The MotoHawk OBD blockset aids in satisfying some of the low-level software requirements of an OBD-compliant fault manager.

First, it’s worth noting that the MotoHawk OBD blockset does not include any of the custom fault-setting logic for comprehensive components or major monitors, as this tends to be very application-specific. Instead, like the classic MotoHawk fault manager, the OBD fault manager provides tools to aid the engineer in handling some of the low-level and tedious details. Some primary features of the MotoHawk OBD blockset:

• Fault Definition block: This block inputs the suspected status of a fault, and sets other common statuses found in the OBD regulation, such as ready, pending, confirmed, MIL-on, permanent, failed this drive cycle, etc.
• Mark To Clear block: There is often different logic to clear fault statuses between OBD regulations or even within a single OBD regulation. This block gives the application engineer a method to achieve this in the application.
• Numerator and Denominator blocks: These blocks aid in keeping track of numerators and denominators for those monitors required to track in-use ratios.
• Drive Cycle Complete block: The application triggers this block to indicate completion of a drive cycle. As in the OBD regulation, fault statuses, numerators, denominators, etc., all are impacted by the definition of a drive cycle.
• Fault Action block: In calibration, a fault action can be tied to any fault with any status.

For more information on each individual block just click on the block and select the Help option. A window will open up explaining the block and how it works.

More Information

OBD Fault Manager Introduction