초록 ▼

The operational fitness of a magnetic sensor for detecting buried magnets can be tested from time to time by an electromagnet installed in proximity to the sensor. The electromagnet is a small coil of wire mounted near the sensor, such as a Hall effect device, which when energized, generates a test

The operational fitness of a magnetic sensor for detecting buried magnets can be tested from time to time by an electromagnet installed in proximity to the sensor. The electromagnet is a small coil of wire mounted near the sensor, such as a Hall effect device, which when energized, generates a test magnetic field. The analog output of the sensor is compared with preestablished values when the electromagnet is energized to verify the proper operation of the sensor; it is also compared with preestablished values when sensing buried magnets to confirm operation of the sensor, the strength of the buried magnet, and the alignment of the sensor with respect to the magnet. A threshold detector senses the output of the sensor to indicate when a magnetic field is detected, and the peak analog output of the sensor is stored and compared to a reference after the sensor passes the magnet. The sensors are normally tested whenever the vehicle is initially powered up or after the vehicle has been stopped for a predetermined time.

대표청구항 ▼

[ What is claimed is:] [1.] A method of testing an end of aisle control system for a wire guided vehicle wherein at least one magnet sensor is positioned on an operator controlled materials handling vehicle for detecting magnets installed in the floor relative to a guide wire for indicating a specif

[ What is claimed is:] [1.] A method of testing an end of aisle control system for a wire guided vehicle wherein at least one magnet sensor is positioned on an operator controlled materials handling vehicle for detecting magnets installed in the floor relative to a guide wire for indicating a specific location, the method comprising the steps ofgenerating an analog output signal representing the strength of the magnetic field detected by said magnet sensor,generating a threshold output signal for said magnet sensor indicating when the analog output signal therefrom exceeds a first predetermined value,detecting and holding a peak value of said analog output signal generated by said magnet sensor during an interval when said threshold output signal is present,determining whether the peak analog output signal of said magnet sensor exceeds a second predetermined value after a threshold output signal has been generated, andindicating a first fault condition whenever the peak analog output signal from said magnet sensor is determined to be below said second predetermined value.