In a nonservo traverse system, which device is typically used by the PLC to stop the motor at the end of travel?

• A. Limit switches
• B. Proximity sensors
• C. Encoders
• D. Photoelectric sensors

Answer: (A)

In a non-servo traverse system, a limit switch provides a definite end-of-travel signal to the PLC. As the moving carriage reaches the end, the switch actuator is pressed, creating a clear on/off input that tells the PLC to stop the motor. This setup is simple, inexpensive, and highly reliable for repeated use, giving a hard, immediate stop without needing any feedback from a position sensor. Other sensors can detect presence or distance, but they’re less robust for guaranteeing a precise end-of-travel stop in an open-loop arrangement, and encoders are tied to closed-loop control used with servo systems rather than basic non-servo setups.