Fail-safe device for electronic control circuit
US4398233A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1982 |
| Grant date | Aug 9, 1983 |
| Priority date | — |
| Expiry date | Mar 3, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B9/02
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A fail-safe device is disclosed for removing power from circuitry to be controlled upon the occurrence of an undesired operating condition. The device includes circuitry for generating a fail-safe signal that is normally within a predetermined frequency range unless there is an undesired operating condition. It also includes power control circuitry for supplying power to the circuitry to be controlled only when the fail-safe signal is within the predetermined frequency range. In a preferred embodiment, the circuitry for generating the fail-safe signal includes a programmable computer which regulates the circuitry to be controlled and which, unless there is an undesired operating condition, such as a failure of the computer, also generates a sequence of bits in which a predetermined pattern occurs at a known frequency. A comparater circuit compares this sequence of bits with the predetermined pattern and generates a variation in the fail-safe signal each time there is a match. In the preferred embodiment, the power control means includes an electromechanical relay for supplying power to the circuitry to be controlled when that relay is turned on and relay actuating circuitry for kee…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.