Computer integrated manufacturing system

A multilevel computerized process control system, comprising:

• a first level computer system comprising at least one first computer for controlling a plurality of individual processes for producing a plurality of different products, said first level computer system comprising:
• a plurality of sensor inputs for receiving process monitoring sensor signals from sensors at respective process stations as well as sensors for receiving indications of material levels of products in process,
• a plurality of control outputs for providing control signals for processes to be controlled,
• storage for storing process control parameters for processes to being carried out,
• storage for storing bill of materials records containing indications of materials necessary for products being produced;
• storage for storing values of said sensor signals, and
• programs for producing said control signals to control said processes as a function of said sensor signal values and said process control parameters for processes being carried out;
• a second level computer system comprising at least one second computer connected to said first level computer system and storing a first database having a plurality of files containing process control parameters associated with different processes which may be required to be performed by said first level computer system to produce different products, said files including a process specification file containing records indicating process control prameters necessary for producing said different products, and a bill of materials file containing records indicating materials necessary for producing said different products, and a second database storing plant production and inventory records containing inventory levels and plant production data, said second level coputer system:
• p1 being connected to receive scheduling information indicative of scheduled process controls to be carried out by said first level computer system to produce scheduled products,
• being programmed to provide selected ones of said control parameters necessary to carry out said scheduled process controls to said first level computer system as said control parameters for processes being carried out and to provide selected records from said bill of materials file indicating materials necessary for producing said scheduled products as said materials for products being produced,
• being programmed to receive indications of said values of said sensor signals and update said plant production and inventory records;
• and
• a third level computer system connected to said second level computer system, said third level computer system being programmed to generate said first database and transmit said first database to said second level computer system and being connected to receive modification instructions for modifying records of said first database, said modification instructions being contained in a modification instruction file containing information for modifying said records of said first database and information as to times at which modifications to said records of said first database are to be implemented.