US 4,819,149 AGranted

Distributed control system

AssigneeOwens-Corning Fiberglas Corporation

InventorsPaul S. Sanik, Dennis H. Shreve, Eugene C. Varrasso

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Abstract

A hierarchical distributive control system is disclosed. The lowest level of the system is a stand alone controller with hot plug in capability, which can accept either analog or digital signals, scale these signal with input subroutines, perform any one of a number of algorithms to produce control signals or can manually produce control signals and output these control signals as either analog or digital signals to field devices. A plurality of controllers communicates with an associated condenser over duel parallel digital communication buses with a full echo, verify communication routine. The condenser contains all records for all controllers under its supervision and can download control information into any replaced controller. A subhost is interconnected to a group of condensers and contains all records contained in all condensers under its supervision. All information can be uploaded from condensers to subhost or downloaded from subhost to condenser. In case of any failure in any subsystem, all lower level systems continue to operate. All controllers are interchangeable.

Claims28

Dependent claims

A process control system comprising:

a plurality of identical controllers, each controller controlling at least one process parameter, each controller including an input means for receiving an input signal corresponding to the value of a measured parameter;
means within said controller for calculating an output control signal based upon said input signal;
output means within said controller for sending said output control signal to a device being controlled;
a plurality of identical condenser means selectively connectable to a group of said plurality of controllers each of said condensers able to initiate communication with each of said controllers connected thereto for receiving process data and for varying the operation of said calculating means within said controller wherein each of said controllers connected to said condenser means is operable in said process without aids condenser means;
a plurality of identical subhost means selectively connectable to a group of said plurality of condenser means each of said subhost able to initiate communication with each of said condenser connected thereto for receiving process data and for varying the operation of said calculating means of said controllers connected to said condenser means wherein each of said condenser means connected to said subhost is operable in said process control without said subhost means;
and
a host computer selectively connected to all subhost means for receiving process data wherein each of said subhost means is operable in said process control without said host computer.

4 more elements

A distributed process control system comprising:

a plurality of interchangeable identical controllers, each controller including an input means for receiving an input signal corresponding to the value of a measured parameter;
a plurality of control algorithms contained within said controller to perform calculations upon said input signal;
means to select a particular algorithm to perform calculations upon said input signal to produce an output control signal;
means to transmit said output control signal to field devices to control a process;
means integral to said controller to display a representation of said input signal and said output control signal;
means integral to said controller to manually set and adjust said controller output control signal;
a plurality of identical condenser means, each of said condenser means selectively connectable to each of a group of the plurality of said controllers by a control bus, an input communication bus and an output communication bus;
means integral with said condenser for communicating with each of said controllers connected to said condenser over serial input and output communication buses for selectively receiving or sending process data and for varying the operation of said selected algorithm within said controller;
a subhost means selectively connectable to each of a group of the plurality of said condenser means by a serial communication bus;
and
means integral with serial subhost for communicating with each of serial condensers connected to serial subhost for selectively receiving or sending process data and for varying the operation of said selected algorithm within controllers connected to said condensers.

8 more elements

A process control system comprising:

a plurality of controllers, divided into groups of controllers;
a plurality of condensers, divided into groups of condensers, each of said condensers connected to a group of controllers by means of a control bus, an input communication bus, an output communication bus and at least one attention line wherein each controller connected to said condenser is operable in said process without said condenser;
a plurality of subhosts, each of said subhosts connected to a group of condensers by means of a first daisy-chained serial communication line wherein each condenser and each controller connected to each condenser is operable in said process without said subhost;
a host computer connected to all subhosts by means of a second daisy-chained serial communication line, wherein each subhost, each condenser connected to each subhost and each controller connected to each condenser is operable in said process without said host computer;
each controller including:
a first input means for receiving an input signal corresponding to the value of a measured parameter;
a second input means for receiving parallel digital data from said condenser over said input communication bus;
a microprocessor means for controlling the operation of said controller;
a memory means for storing information for operating said microprocessor;
program means stored in said memory for operating said microprocessor including communication subroutines, input scaling subroutines, alarm subroutines and algorithms for calculating a first control signal;
a manual control means for manually producing a second control signal and for inhibiting said first control signal;
a visual display means for selectively displaying information within said controller;
a first output means to transmit said control signal to a field device which is to be controlled;
a second output means for sending parallel digital data to said condenser over said output communication bus;
each condenser including:
a first input means for receiving a plurality of input signals from field devices;
a second input means for receiving parallel digital data from said controllers on said output communication bus;
a third input means for receiving serial data on said first daisy-chained serial communication line from said subhost;
a microprocessor means for controlling the operation of said condenser;
a memory means for storing information from said controllers and said subhost and for storing information for operating said microprocessor;
program means stored in said memory means for operating said microprocessor;
a keyboard means for entering information into said condenser;
a visual display means for selectively displaying information in said condenser;
a first output means to transmit information to field devices;
a second output means for sending parallel digital data to said controllers over said input communication bus;
a third output means for sending serial data over said first daisy-chained serial communication line to said subhost;
each of said subhost including:
a first input means for receiving serial data from said condensers over said daisy-chained serial communication line;
a second input means for receiving serial data from said host computer over said second daisy-chained serial communication line;
a microprocessor means for controlling the operation of said subhost;
a memory means for storing information from said condensers and from said host computer and for storing information for operating said microprocessor;
program means stored in said memory means for operating said microprocessor;
keyboard means for entering information into said subhost;
visual display means for selectively displaying information in said subhost;
a first output means for sending serial data over said first daisy-chained serial communication line to said condensers;
and
a second output means for sending serial data over said second daisy-chained serial communication line to said host computer.

34 more elements

Dependencies are inferred from the claim text.