Specification of Reactive Hardware/Software Systems - Electronic ...

3.6 Practical Use of Concepts 39
3.6.1 Introduction to the Case Study: The Existing Mailing Machine
The case study in this thesis concerns the specification and modelling of the control
subsystem of a new generation of mailing machines. A mailing machine performs the
preparation of product packets to be mailed. Packets contain in general printed matter
such as for example one or more magazines, advertising material, etcetera. The machine
can wrap (envelop) a packet in paper or plastic foil, print a post address, and stack the
packets. Figure 3.2 shows a very simplified view of a mailing machine. This machine
Control station
Feeder Feeder Feeder Wrapper Separator Stacker
Figure 3.2: Simplified Mailing Machine
consists of a line of mechanical stations and a control station that contains processors
that control the machine. In general, the first (left in Figure 3.3) feeder of a line lays
Control station
Feeder Feeder Feeder Wrapper Separator Stacker
Figure 3.3: Interconnect Structure of Mailing Machine
down (feeds) magazines into the production line. The production line transports these
magazines. They pass the wrapper where they are packed in foil. A separator station
cuts the foil and can for example print mailing addresses on the packets. Subsequently
a stacker station creates bundles of packages to be sent away. There are three feeders in
this example. A second feeder can be a station that adds another magazine to a packet.
Another type of feeder can blow open magazines and adhere an advertisement card into
them.