Patent Number: 050680803
Section: summary

MICROFICHE APPENDIX A microfiche appendix is included herewith which contains one fiche and nineteen total frames. CROSS REFERENCE TO RELATED APPLICATIONS The present invention is related to allowed U.S. Pat. Nos. 4,803,039 and 4,815,014 respectively filed on Feb. 3, 1986 and Feb. 27, 1987 both of which are incorporated by reference herein. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a digital computer based system for selecting information to be presented to an operator of a processing facility as he executes complex operations and, more particularly, to a system in which the automatic selection of new displays of information is internally triggered by detected changes in plant state that occur as a result of the ongoing operations and where the selection process is guided by the observed sequence of such plant state changes. 2. Description of the Related Art U.S. Pat. Nos. 4,803,039 and 4,815,014 teach the basic concepts underlying a system for computer based monitoring of the execution of complex procedures. It is recognized that such a system is primarily intended for use under circumstances in which the operator of a complex processing facility is faced with an unusual, adverse situation with little or no prior experience therein. Under such circumstances the operator has little choice but to rely heavily on, and follow closely, pre-planned, written procedures, defined usually by the systems' designers, in order to attempt to restore critical system functions. In such cases frequent interaction between the operator and a computer based monitor of procedures execution, such as the system referenced above, is highly desirable if undesirable consequences are to be avoided. In another class of more commonly encountered operating situations the operator of a complex processing facility performs a nearly routine operation. The startup after shutdown of a large electrical generating plant, which might typically occur several times a year, is representative of this class of situations. These situations inevitably involve programmed sequences of changes in the state of the plant. These changes in state may be as pervasive as changes in temperature or pressure of a working fluid or as simple as the opening or closing of a valve, or the starting or stopping of a pump. By ordinary and broadly accepted industry standards and practices such changes in state are monitored and may serve to trigger the next step in the human controlled evolution of the operation being carried out. The operator usually has had prior experience in such situations, but by reason of infrequency of occurrence he may not remember every detail of the sequence of operations to be performed. Such situations are not hazardous and in general pose no threat to the health and safety of either the operators or the general public. They are of interest to the owners and managers of the affected facilities because errors made in the execution of the operations can be quite costly in terms of lost production and in equipment damage resulting from incorrect sequencing of consecutive operations. Written procedures or a preplanned sequence of operations to guide the operator in efficiently executing the desired nearly routine sequence of operations commonly exist in complex processing facilities. Nonetheless, costly operator errors occasionally occur as a result of an operator's misunderstanding of particular parts of the applicable procedure or of inadvertent omission of one or more steps of the procedure. Hence, the use of a computer based system for monitoring the execution of such nearly routine sequences of operations can again offer valuable benefits. Attempts to apply the system of the above-identified applications to this class of operations where the operator is nominally familiar with the course of actions to be followed have consistently shown that such systems are too rigorous and too demanding of operator interactions to be fully practical. SUMMARY OF THE INVENTION It is an object of the present invention to provide a computer based system which has the ability to utilize internal recognition of successive changes in monitored system state to stay in step with the actual execution of a currently applicable sequence of operations. It is a further object of the present invention to provide a system which detects impending or just committed operator errors and automatically provides output displays alerting the operator to the deviation from the sequence of operations along with other displays showing the evolution of the affected plant systems. It is an additional object of the present invention to provide a monitoring system which automatically generates a textural display indicating a deficiency in the accomplishment of a step in an operation, detailing the evidence that identifies the deficiency and setting forth the actions needed to rectify the situation. It is also an object of the present invention to provide a system which when the operator has completed corrective actions, confirms completion of the previously deficient step and automatically passes to consideration of the next step in sequence. It is an object of the present invention to provide a computer based system which effectively assists in the execution of nearly routine operations of a plant which provides minimally obtrusive support to the plant operators in carrying out a prescribed evolution of plant states. It is still another object of the present invention to transfer at least part of the burden of continuously monitoring peripheral aspects of the evolution of a plant from the human operator to a computer. It is also an object of the present invention to automatically collect, organize and present information relative to the current transition in plant state in a single convenient location and to automatically document the process as it evolves. The above objects can be accomplished by a computer based system for supporting plant operators in carrying out prescribed nearly routine procedures or a preplanned sequence of operations. The computer based system monitors available plant instrumentation signals and processes the gathered information to detect successive changes in plant state. The system then compares the sequence of observed changes in plant state with a preprogrammed sequence and draws the operators attention to any undesirable deviations from the preplanned sequence by providing appropriate displays on a system monitor. The system requires no input from the operator when the operation underway is following the prescribed sequence and minimal input from the operator when a deviation is detected. The system internally and automatically tracks the evolution of plant states during the nearly routine operations. These together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.