In China, for middle and large sized grenades, the widely used detonator loading method is the procedure press-charge detonator method. This method features high efficiency, good quality, and stable; but the electromechanical control system of existing procedure press-charge detonator machine is mainly using relays, so it is not reliable and poor in adaptability for variable species and technological processes, as well as complex wiring and difficult maintenance. The PLC control system, due to using the large scale integrated circuits and advanced anti - interference technology, is highly reliable and provides advantages of anti -interference capability, comprehensive functions, easy to reconstruct and maintain, compact, low power consumption, etc. , so it can well solve the problems above. Anyhow, the programming for ladder diagram of PLC is difficult, and the traditional PLC programming method cannot meet the requirements for some of the complex industrial controls, such as coordinated control and competition control. Aiming at these problems, a new design method of PLC ladder diagram is put forward, i. e. , the Petri net method. The building method of Petri net control model and the conversion relationship between Petri net model and ladder diagram are introduced in detail, and the Petri net modeling for procedure press - charge detonator technology is achieved by using this programming method; and this control model is converted into PLC control program. The practical simulation tests show that the control system can well meet the control requirements of production control.%我国中大口径榴弹广泛采用分步压装药法,该方法装药效率高、质量好、稳定,但分步压装药机机电控制系统以继电器为控制主体,该机电系统存在控制过程不可靠、变品种变工艺适应能力差、接线复杂和维修维护困难等问题.而PLC控制系统由于采用大规模集成电路和先进的抗干扰技术,具有可靠性高、抗干扰能力强、功能完善、容易改造、维护方便、体积小、能耗低等优点,因而能很好地解决上述问题.但PLC梯形图编程困难,且传统的PLC编程方法无法满足诸如协调控制、竞争控制等复杂工业控制要求.针对以上问题提出了一种新型PLC梯形图设计方法——Petri网法,详细介绍了Petri网控制模型的建立方法以及Petri网模型与梯形图的转换关系,采用该编程方法完成了分步压装药工艺流程的Petri网建模,并将该控制模型转换为PLC控制程序.实际仿真测试表明,该控制系统能很好地满足生产控制要求.
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