基于S7-200SMART PLC的散粮装卸系统设计与优化

散粮装卸是粮食运输中重要的环节，而散粮装卸系统具有设备繁多、设备之间相关性复杂等特点，因此需要采用结构化程序设计方法，对不同系统的功能和各个工艺环节的特性进行分析，并按层次划分系统的控制结构。

PLC控制系统是两用机的大脑，所有控制指令全部需要通过PLC来进行输出，各个设备的保护、上下游设备间的联锁作业全部由PLC实现。本文通过不同的PLC核心控制器各方面的数据等对比后，散粮装卸系统最终采用西门子小型PLC S7-200SMART，上下电气室之间使用网络通信，通过对比优化多种电气控制系统解决了上下电气室之间通信不稳定、备件无法购置等问题。

硬件和软件方面，通过模块接口之间优缺点的对比调试后，择优选用的同时还根据实际装卸可能发生的情况，对其进行升级改造后运用于本文的设计系统中。最后还通过设计通讯模块实现了整个流程的统筹兼顾，便于技术人员的故障诊断处理。

传统工业自动化领域的控制结构已经形成了以PLC为基础、工业以太网为通讯手段的控制系统。工业以太网是一种高速度、高确定性和可重复性的网络，采用多信道广播式定点传送，适用于对时间苛刻要求、需要控制的输入输出点数巨大的系统。本文针对散粮装卸系统工艺流程和设备繁多且设备之间的相关性较为复杂等特点, 通过对比国内外研究现状采用结构化程序设计方法, 着重于软件设计的模块化和层次化, 对不同系统的功能和各个工艺环节的特性进行分析, 按层次划分系统的控制结构, 并设计了以S7-200SMART为核心控制器的系统，并优化了相应的软件模块, 大大提高了散粮装卸时的效率，还提高了系统整体的安全性与合理性。

摘要

The PLC control system serves as the 'brain' of the dual-purpose machine, where all control instructions need to be output through the PLC. The protection of various equipment and interlocking operations between upstream and downstream devices are all implemented by the PLC. This paper compares different aspects of data from various PLC core controllers and ultimately adopts the Siemens small PLC S7-200SMART for the bulk material loading and unloading system. Network communication is used between the upper and lower electrical rooms to optimize multiple electrical control systems and solve problems such as unstable communication between the upper and lower electrical rooms and the inability to purchase spare parts.

In terms of hardware and software, after comparing and debugging the advantages and disadvantages of module interfaces, we selected and upgraded them based on actual loading and unloading scenarios, and used them in the designed system in this paper. Finally, a communication module is designed to achieve overall coordination of the entire process, making it easier for technical personnel to diagnose and handle faults.

Bulk material loading and unloading is an important link in grain transportation, and the system has the characteristics of complex equipment and complex interrelationships between equipment. Therefore, a structured program design method is needed to analyze the functions of different systems and the characteristics of each process step, and divide the control structure of the system according to the hierarchy.

The control structure of the traditional industrial automation field has formed a control system based on PLC and industrial Ethernet as the communication method. Industrial Ethernet is a high-speed, high-deterministic, and repeatable network that uses multi-channel broadcasting and point-to-point transmission, which is suitable for systems with a large number of input and output points that require strict time requirements and control. In this paper, based on the characteristics of the bulk material loading and unloading system process flow and the complex interrelationships between equipment, we adopt a structured program design method through comparing domestic and foreign research status. We focus on software design modularity and hierarchy, analyze the functions of different systems and the characteristics of each process step, divide the control structure of the system according to the hierarchy, and design a system with S7-200SMART as the core controller. We also optimized the corresponding software modules, greatly improving the efficiency of bulk material loading and unloading, and improving the overall safety and rationality of the system.