Method and apparatus for monitoring the proper operation of a control system for materials handling vehicles
US6009357A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 1994 |
| Grant date | Dec 28, 1999 |
| Priority date | — |
| Expiry date | May 2, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05D1/0265
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.