A rotary table timing sensor is often a ________ sensor because the tables Metal and is low cost sensor.

• A. Inductive
• B. Capacitive
• C. Optical
• D. Ultrasonic

Answer: (A)

Inductive sensing is ideal here because it detects metal targets through changes in a magnetic field. The rotary table is metal, so when it passes near the sensor, eddy currents are induced in the metal, changing the sensor’s impedance and producing a clean timing pulse. This approach is fast, reliable, and well-suited for the machining environment—oil, chips, and dust don’t easily interfere, and the sensors are typically inexpensive and rugged.

Other sensor types would struggle in this situation. Capacitive sensors respond to changes in the dielectric between plates and can be affected by moisture or non-metal materials; optical sensors require a clear line of sight and can be fouled by dust and oil; ultrasonic sensors measure distance and are slower and less cost-effective for high-speed timing signals.