A new proposal for the behaviour model of batch phases.

There is a problem with managing the complexity and meeting the high-quality requirements of batch-process control software in the environment of the modern tools for batch-process control according to the ISA 88.00.01 standard. The problem stems from the insufficient abstraction level of the phase-behaviour model consisting of only five active sequences. A solution to this problem is proposed, based on increasing the level of abstraction of the phase-behaviour model by adding to it the nested states and in defining an increased number of finer-granularity activities. The new concept, together with its elements, is described, and its use is illustrated by means of the specification of a phase from a real batch-control project.