US 5,325,522 A · Apparatus and method for communicating between devices trough use of a real time data base

Abstract

A control system (10) controls transfer of electronic signals to and from industrial and scientific equipment. The control system includes a real-time database (60) for storing data elements which may be accessed by a plurality of tasks (62, 64, 66, 68, 70, and 72). Each data element in the real-time database (60) has an associated changed status flag for each task which indicates whether the value of the element has changed since the last access by the task. Individual tasks must communicate through the real-time database, since no inter-task communication is supported. The tasks support bidirectional communication with industrial and scientific equipment, alarm supervision, data logging, real-time clock functions, mathematical and logical functions, and interactive operator communications.

Claims20

Dependent claims

Apparatus for communicating between input/output devices each associated with at least one of a plurality of processes, comprising:

a database memory comprising a plurality of memory elements, said memory elements operable to receive data from and transfer data to processes associated with said memory elements;
status circuitry associated with each memory element and further associated with at least one of said plurality of processes, said status circuitry operable to indicate that contents of a specific memory element have changed since a last previous transfer of data from said specific memory element to said processes;
and
communication circuitry associated with the devices for transferring data from the database memory to the processes associated with said specific memory element in response to said status circuitry indicating a change in contents of said memory element.

1 more element

Dependencies are inferred from the claim text.

Apparatus and method for communicating between devices trough use of a real time data base

Life of this patent

Apparatus and method for communicating between devices trough use of a real time data base

Life of this patent

Abstract

Claims20