PLC梯形图转化为多操作数逻辑指令的设计与实现

Design and Realization of Transformation from PLC Ladder Diagram to Multiple Operands Logic Instruction

摘要:

针对每一个操作数有一个操作码的PLC逻辑指令,设计了一个操作码可带多个操作数,操作数附加“辅助符号位”的新型PLC逻辑指令,避免在执行逻辑指令过程中有多少个操作数需要译码多少次的状况;研究这种新指令语句的数据结构和梯形图的数据结构,应用这两种数据结构研究梯形图转化成新指令表的转化算法；对梯形图采用按梯级顺序递归扫描方法构造二叉树结构,然后对二叉树进行后序遍历得到一个中间结果指令表,对中间结果指令表经过逻辑关系的分析与同类型逻辑关系操作数的合并处理得到最终的指令表;通过对串并联结构梯形图的转换测试,其新指令语句的转化结果正确。

Abstract:

Each operand in PLC logic instructions contain only an opcode. A new type of PLC logical instruction structure is designed, where its operation code can take multiple operands and its operands additional "auxiliary sign bit". It avoids in the process of execution logic instructions for multiple operands to decode several times. Researched on the data structure of this new instruction statement and the data structure of the ladder diagram, and using these two data structures to achieve the transformation algorithm of the ladder diagram into the new instruction list. Ladder diagram used in cascade order recursive scanning methods constructing binary tree structure, and postorder the tree traversal for an intermediate result instruction list, After the analysis of the logical relationship of intermediate result instruction list and combined process of operation for the same type of logical relations, the final instruction table is obtained. Through the series-parallel structure of ladder diagram transformation test, the new instruction statements transformation result is correct.