1.5 Vertical and Horizontal Integration

In the past a two-layer model arose automatically from the two levels of automation and ERP. In most cases information was exchanged manually between the two layers.

The connection between the levels of corporate management and of production was thus a very indirect one and communication cycles were designed with a resolution of several days. With the development of the MES concept, even production management, as seen from the IT side, became a distinct discipline. It has now become possible to assign really specific fields of action to the three levels of corporate management, production management and production. In its dealings with ERP or PPS, corporate managements tend to work on a long-term basis with a resolution of weeks or months. Rough production planning deals with a medium-term range of weeks or days, while detailed planning also known as load planning acts in the short term in days and shifts. Decisions taken within production management must be made within a time range extending from shifts down to minutes while automation with its machine and plant control systems needs, of course, to react within minutes or even seconds.

The corresponding diagram symbolizes a control characteristic within the different levels whereby the control cycles run within the time resolutions shown. There are, of course, no precise boundaries between the three levels of a manufacturing company. Accordingly, between ERP and MES we find the APS (advanced planning and scheduling) functions which, depending on the type of...