摘 要
汽包水位是影响锅炉安全运行的一个重要参数，汽包水位过高或者过低的后果都非常严重，因此对汽包水位必须进行严格控制。PLC技术的快速发展使得PLC广泛应用于过程控制领域并极大地提高了控制系统性能，PLC已经成为当今自动控制领域不可缺少的重要设备。
本文从分析影响汽包水位的各种因素出发，重点分析了锅炉汽包水位的“假水位现象”，提出了锅炉汽包水位控制系统的三冲量控制方案。按照工程整定的方法进行了PID参数整定，并进行了仿真研究。根据控制要求和所设计的控制方案进行硬件选型以及系统的硬件设计，利用PLC编程实现控制算法进行系统的软件设计，最终完成PLC在锅炉汽包水位控制系统中应用。
关键词：汽包水位、三冲量控制、PLC、PID控制
ABSTRACT
The steam drum water level is a very important parameter for the boiler safe operation, both high and low steam drum water level may lead to extremely serious consequence; therefore it must be strictly to be controlled. With the rapid development of PLC technology, it can widely be applied to the process control domain and enhances the performance of control system enormously. PLC has already become the essential important equipment in automatic control domain.
Based on the analysis of all kinds of factors which influence steam drum water level, “unreal water level phenomenon”is analyzed specially, and three impulses control plan for steam drum water level control system is proposed. According to the needs of control, the selection of control requirements hardware and system hardware design as well as system software design are carried out. Finally the application of PLC in boiler steam drum water control system is completed.
Key words: Steam drum water level、Three impulses control、PLC、PID control
目 录
摘 要………………………………………………………….Ⅰ ABSTRACT………………………………………………….Ⅱ
1 绪 论 ................................................................................................. 1
1.1汽包水位控制系统的发展现状 ................................................................ 1 1.2汽包水位调节的任务 ................................................................................ 2 1.3本设计的主要工作 .................................................................................... 2
2 控制方案设计 ..................................................................................... 3
2.1虚假水位的形成及对策 ............................................................................ 3 2.2汽包水位的影响因素 ................................................................................ 4 2.3汽包水位的控制方案设计 ........................................................................ 6
3 硬件选型 ........................................................................................... 14
3.1PLC及相关模块选型 ................................................................................ 14 3.2电机的选型 .............................................................................................. 14 3.3变频器的选型 .......................................................................................... 15 3.4水位传感器的选型 .................................................................................. 15 3.5流量传感器的选型 .................................................................................. 16 3.6接触器的选型 .......................................................................................... 17 3.7熔断器的选型 .......................................................................................... 17 3.8功率三极管的选型 .................................................................................. 18 3.9变压器的选型 .......................................................................................... 18 3.10设备清单 ................................................................................................ 19
4 硬件设计 ........................................................................................... 20
4.1系统总体线路设计 .................................................................................. 20