Description
The SD101201 has two Hall Effect sensors; one detects speed and the other detects direction of movement of gear teeth. The outputs are open collector transistors. The Speed output goes low (ON) when sensing the leading edge of a tooth and high (OFF) at the trailing edge of the tooth when run against a standard target (see diagram). The Direction output goes low (ON) for clockwise rotation and high (OFF) for counterclockwise rotation (as seen in the diagram); it is latched in that state as long as there is movement detected. The state of the Direction output always leads the rising edge of the Speed output – correct Direction sensing will occur faster after start-up than correct Speed sensing. An external pull-up resistor is required.

FEATUREs
• Separate digital outputs for speed and direction
• From near zero speed up to 15 kHz sensing capability
• Plastic flange-mount sensor rated to 125 ⁰C
• RoHS compliant
• IP67
• Typical air gap of 1.5 mm (0.06”)*

Typical Applications
• Wheel speed and direction
• Hoist speed and direction
• Transmission speed and direction
• Industrial feedback and control