Normalized Systems theory has recently been proposed to engineer evolvable information systems. This theory includes also a potential of improvement in control software for the automation of production systems. In production control systems, the end user has always the right to have a copy of the source code. However, it is seldom manageable to fluently add changes to these systems, due to the same problems as information systems: couplings, side-effects, combinatorial effects, etc. Finding

more »

... tions for these problems include several aspects. Some standards like ISA 88 suggest the use of building blocks on macro level. The OPC UA standard enables these building blocks to communicate and interoperate over the borders of the hosting controllers via local networks or the internet. Consequently, production data collection, manual interfaces and recipe driven production control systems become web service based. Finally the Normalized Systems' theory suggests how these building blocks should be coded on micro level. This paper introduces a control module, based on a design pattern for flexible manufacturing and the principles of Normalized Systems for evolvable software.