METHOD FOR DIAGNOSING A VARIABLE RELUCTANCE MAGNETIC DETECTION HEAD, AND DETECTION CIRCUIT

摘要

A variable-reluctance magnetic detection head delivers an electrical signal (Uin) and a rising wavefront of the electrical signal is compared with a first threshold (Th) in order to switch from a first state (B0) to a second state (B1), and a falling wavefront is compared with a second threshold (Tb) lower than the first threshold (Th) in order to switch from the second state (B1) to the first state (B0). In a diagnostics step, the first threshold (Th) or the second threshold (Tb) is modified, bringing these thresholds closer together, and a magnetic detection head is diagnosed as being defective if the duty cycle of the second state (B1) is modified during the diagnostics step by a value higher than a diagnostics threshold predetermined in relation to a reference level.

主权项

1. A diagnostics method for a variable-reluctance magnetic detection head (2) delivering an electrical signal (Uin), whereby a rising wavefront is compared with a first threshold (Th) in order to switch from a first state (B0) to a second state (B1), and a falling wavefront is compared with a second threshold (Tb) lower than the first threshold (Th) in order to switch from the second state (B1) to the first state (B0), characterized in that, in a diagnostics step, the first threshold (Th) or the second threshold (Tb) is modified, bringing these thresholds closer together, and a magnetic detection head (2) is diagnosed as being defective if the duty cycle of the second state (B1) is modified during the diagnostics step by a value higher than a diagnostics threshold (S) predetermined in relation to a reference level.