Process facility monitor using fuzzy logic

A monitoring system for an electrical power generating plant comprising:

• a storage unit to store planned sequences of hypothesized plant states, each plant state defined by a congruence factor calculated using multi-valued logic;
• a data acquisition and conversion system to repeatedly obtain plant data and convert the hypothesized plant data representing the electrical power generating station into multi-valued logic variables;
• a processor to determine at least one current sequence as likely in progress from among the planned sequences stored in said storage unit, to calculate the congruence factor from the multi-valued logic for each hypothesized plant state in each of the at least one current sequence and to identify a current plant state for each of the at least one current sequence based on a highest congruence factor;
• wherein said processor determines the at least one current sequence as having entrance conditions evaluated as true and exit conditions evaluated as false, wherein true and false are each defined as a range of values in the multi-valued logic;
• and
• a display unit to display information about the current plant state in dependence upon the values of the multi-valued logic variables regardless of whether the information is used to identify the current plant state.