ABSTRACT
Computer systems have been continually adapted to process control, however, with an emphasis on continuous processes. In the 1970s programmable controllers (PLC) were applied in control of batch processes in the chemical industry. A major breakthrough came in the 1980s when computer manufacturers developed batch control systems for mini- and microcomputer systems. The scope of batch computer applications is usually different from the scope of a PLC application. The analogy between a batch process and the start-up of a continuous process is that in both cases the operation is time dependent; however, in a continuous process, start-up occurs only once. Batch control logic is more complicated than a continuous control application, and, therefore, changes to the program logic will be more time consuming than changes to a control strategy in a continuous process environment. Two main categories of processes can therefore be distinguished: batch processes in which components react and processes without reaction.
