Methodology for manipulation of Karnaugh maps designing for pneumatic sequential logic circuits

摘要

This paper presents an alternative way to use the Karnaugh maps, which minimises logical conditions used for ON/OFF control, in either pneumatic and electro pneumatic circuits. In the last case, the methodology allows the control of the circuit through a programmable logic controller (PLC). In this kind of processes, controlling pneumatic cylinders is a problem that not only depends on the state of the information present but also in terms of knowledge of past actions. In practice, ensuring a series of sequential movements in an automatic cycle is to find the set of equations that should be executed to ensure the realisation of the desired sequence. It means therefore that the equations that will allow the movements of each cylinder are functions only of two types of input variables, the position of each cylinder and if necessary, memory variables. One of the major merits that arise from the use of the proposed method is the simplicity of obtaining electrical schematic command circuit. The proposed methodology ensures not only the desired sequential cycle, as well as the minimisation of the variables necessary for control commands.