| 摘要 |
The arithmetic unit receives data, which may be derived from a memory or the inputs or outputs of the programmable control system itself, one bit at a time via a data input terminal (DATA-IN). In the arithmetic unit, this serial input data is logically linked to instructions which are fed in via corresponding terminals (START, RETURN, AND, CONNECT, INVERT, OUT). The circuit, or the functions triggered by the named instructions, are adapted to the representation of a specific control program in a so-called flow diagram, which symbolises a control program as make contacts and break contacts connected in series or parallel. The AND instruction, for instance, has the effect of closing such a break contact. The operation of the arithmetic unit is controlled by a clock signal, which is fed in at a clock input (CLOCK). The processed data leaves the arithmetic unit at a data output terminal (DATA-OUT). This arrangement allows flow diagrams of any processing depth and any processing width to be processed without redrawing the flow diagrams, and is particularly suitable for programmable control systems (PC). <IMAGE> |
