Programmable controller with back-up capability
US4521871A · kind A · utility
77Cited by
4References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1982 |
| Grant date | Jun 4, 1985 |
| Priority date | — |
| Expiry date | Apr 12, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B19/058
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An active programmable controller services I/O racks which contain circuits that interface with sensing devices and operating devices on a machine being controlled. A back-up programmable controller monitors this I/O data to maintain a current I/O image table in its memory. Other status data is coupled to the back-up controller from the active controller through a peer-to-peer communications link. If a malfunction occurs in the active controller, the back-up controller is signaled to switch to the active mode in which it assumes control of the operating devices on the machine being controlled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.