Function block implementation of a cause and effect matrix for use in a process safety system
US6898468B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 2003 |
| Grant date | May 24, 2005 |
| Priority date | — |
| Expiry date | Aug 11, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B9/02
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A cause and effect function block, which can be easily integrated into a function block diagram programming environment in a process plant safety system to implement the cause and effect logic specified by a traditional cause and effect matrix, includes a set of cause inputs and a set of effect outputs. A multiplexer within the cause and effect function block receives each of the cause inputs and is coupled to one or more state machines, with a separate state machine existing for each effect output. The multiplexer decodes each of the cause inputs and, based on the cause inputs and previously identified cause and effect matrix logic, provides a trip signal to one or more of the state machines. Upon receiving a trip signal, a state machine forces an associated effect output into a tripped or safe state. If desired, the state machine may then use one or more other signals, such as signals from a user or from the process, to transition between a set of different states used to safely return the process plant back to the normal operating state from the tripped or safe state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.