Movable storage unit control system with system resetting watchdog circuit
US4759592A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 12, 1987 |
| Grant date | Jul 26, 1988 |
| Priority date | — |
| Expiry date | Aug 12, 2007 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA47B53/02
- WIPO fieldFurniture, games
- WIPO sectorOther fields
Abstract
A movable storage unit control system is provided with: a leading edge safety tape switch for contacting it to bring a driven unit to a stop; a processor for generating move and stop command signals; a plurality of circuits through which test signals are transmitted under control of the processor and which are returned to the processor coincidentally with their transmission through a current sensor if the circuit tests good; a procedure for having the processor address a test signal to a nonexistent circuit to determine if the current sensor has failed and is allowing return of signals when it should not; circuits for setting minimum and maximum speed of the motors that drive the storage units; a circuit for setting the intensity of dynamic braking of the drive motors; and, a watchdog circuit that shuts down the processor upon occurrence of intense temporary electrical noise or software execution errors and is involved in causing the processor to shut down and block all commands to the system if the processor or other hardware fails.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.