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ISO 11898-1/2 Conformance Testing: Differential Voltage Levels, Ground Shifts & Ringing

Validating dominant and recessive differential voltages (V_diff), common-mode noise rejection, and termination resistance matching across vehicle harnesses.

Physical layer degradation is the leading cause of intermittent CAN bus errors in production vehicles. ISO 11898-2 dictates precise electrical specifications:

• Dominant State: CAN_H nominal at 3.5V, CAN_L at 1.5V, yielding a differential voltage V_diff between 1.5V and 3.0V. • Recessive State: Both lines biased to 2.5V, resulting in V_diff close to 0V (nominal -0.5V to +0.5V). • Common-Mode Shift: Transceivers must tolerate ground potential differences of up to ±12V without bit misinterpretation.

CAN Validation deploys high-speed automated oscilloscopes and dynamic electronic loads to sweep common-mode offsets and verify split-termination matching (60Ω nominal), eliminating high-frequency ringing that triggers unexpected bit errors.