sa unit-2-three-vignets

Three Vignettes in mixed style

Distributed process control

Dr Reeja S RProfessorCSE Dept.SJEC, Vamanjoor, Mangalore

3-Vignettes

• Plan management system– Process control with plant management.

• Information system– Five level layered hierarchy.– 1: process measurement and control– 2:process supervision for monitoring and controlling– 3:Process management- computer based plant automation-

reports, optimization guidance.– 4,5: Plant and corporate management-cost accounting, inventory

control, order processing , scheduling..

Three vignettes in mixed styleThree vignettes in mixed style

• In the above model– Layers 1-3 are object oriented– Layers 4-5 are conventional data repository

model.

Operating parameters: Current process value, target value, output and mode-automatic or manualTuning parameters: gain, reset, derivative, alarm trip-pointsConfiguration parameters: tag-name and I/O Channels

Operating parameters: Current process value, target value, output and mode-automatic or manualTuning parameters: gain, reset, derivative, alarm trip-pointsConfiguration parameters: tag-name and I/O Channels

TemplatesAlgorithmsCommunication services

• Layer 4 and 5: integrates conventional host computer and conventional database management.

• Data collection facilities of level 3 and reporting facilities of level 2 provide process information as transactions processing functions –supports central data store.

Rule based systemRule based system

Rule based system• Pseudocode: code to be executed- knowledge base.• Interpretation engine: Rule interpreter• Control state of the interpretation engine: rule and data

element• Current state of the program Working memory.

IT CALLS SET OF RULES WHOSE CONTROL RELATIONS ARE DETERMINED DURING EXECUTION BY THE STATE OF THE COMPUTATIONIt provides a virtual machine to support this model.

A blackboard globally recast as an interpreterA blackboard globally recast as an interpreter

Black board• Solution is organized into application

dependent hierarchies • Domain knowledge is partitioned into

independent modules of knowledge that operate on knowledge within levels