Most of these systems feature a three- or four-level structure, starting at the lowest level, the sensor level, in which sensitive sensors are installed directly on the production units to record quality and/or production data. They continue to higher levels, e.g. the machine level, where the signals arriving from the sensors are collected, processed and analyzed, and the result often indicated in a simple manner on the machine. The third level is the PC workstation level, where the data collected at machine level are systematically evaluated and displayed in a very informative way in the supervisor‘s office, for instance in the form of graphs.
The top level is usually a commercial host computer. Here again all the information arriving from the second or third level is collected in a condensed and compatible form by a local network, systematically evaluated and displayed in a manner easy to deal with, e.g. in diagram form (Fig. 65). The detailed analysis of the second, (third) and fourth level enables immediate action to be taken wherever anything strays even slightly from the required norm.