基于PLC的电厂供暖系统的设计与实现
摘 要
本文研究的是基于PLC的换热站监控系统，是一个集成了暖通工程、计算机技术和通讯技术的先进解决方案，提升换热站运行的效率与自动化水平。该系统的应用不仅能够实时监测和控制换热站的运行状态，还因其强大的通讯能力和灵活的软件功能，可以支持远程网络化管理，极大地方便了运维人员对多个换热站进行统一监控和调度。关键技术组件及功能西门子S7-200SMART PLC，作为系统的核心控制器，S7-200SMART系列PLC以其高性能、小型化和经济性著称，作为人机交互界面，MT8106IQ提供了直观的操作界面，使得现场操作人员能方便地查看实时数据、调整运行参数和切换控制模式（手动/自动）。这种触摸屏的使用提高了系统的用户友好性和操作便利性。控制方案，系统采取分布式控制策略，即每个换热站拥有独立的PLC控制系统，而监控中心则负责集中管理和调度。这种设计既保证了各个换热站的自治运行能力，又便于集中监控和远程调控，提高了系统的可靠性和灵活性。PID算法功能模块，PID（比例-积分-微分）控制算法是自动控制领域广泛应用的经典算法，用于精确控制二次回水温度等关键参数达到预设目标。通过调整PID参数，系统能快速响应外部变化，有效抑制过冲和振荡，维持温度控制的高精度和稳定性。
实现电厂换热站采暖机组控制系统正常运行，进水给乙二醇溶液加热设备需自带PLC控制，包含相关阀件、泵、传感器、流量采集等一切相关控制及数据采集。外部设备可通过RS485串行通讯读取机组数据。触摸屏显示采暖供/回乙二醇溶液压力、采暖供乙二醇溶液温度，一次侧电动调节阀开度，水泵、电磁阀等开关状态，各种警报信息。其中压力、温度、警报等信息，可存储1年运行数据。触摸显示换热机组系统运行状态图、各种压力温度运行曲线。各种温度、压力等设定值，可通过触摸屏设定。
关键词：PLC，触摸屏，PID，变频器
Design and Implementation of Power Plant Heating System Based on PLC
Abstract
This paper studies the PLC-based heat exchanger station monitoring system, which is an advanced solution integrating HVAC engineering, computer technology and communication technology to enhance the efficiency and automation level of heat exchanger station operation. The application of this system can not only monitor and control the operation status of heat exchanger stations in real time, but also support remote networked management due to its powerful communication capability and flexible software functions, which greatly facilitates the unified monitoring and scheduling of multiple heat exchanger stations by operation and maintenance personnel.
Key Technical Components and Functions Siemens S7-200SMART PLC, as the core controller of the system, S7-200SMART series PLC is famous for its high performance, miniaturization and economy. As the human-computer interface, MT8106IQ provides an intuitive operation interface, which makes it easy for the field operators to view the real-time data, adjust the operation parameters and switch the control mode (manual/automatic). (manual/automatic). The use of this touch screen improves the user-friendliness and ease of operation of the system. Control scheme, the system adopts a distributed control strategy, that is, each heat exchanger station has an independent PLC control system, while the monitoring center is responsible for centralized management and scheduling. This design not only ensures the autonomous operation capability of each heat exchanger station, but also facilitates centralized monitoring and remote control, which improves the reliability and flexibility of the system.PID Algorithm Function Module, PID (Proportional-Integral-Derivative) Control Algorithm is a classical algorithm that is widely used in the field of automatic control, which is used to accurately control the key parameters, such as the secondary return temperature, to achieve the preset target. By adjusting the PID parameters, the system can respond quickly to external changes, effectively inhibit overshoot and oscillation, and maintain high precision and stability of temperature control.
Realize the normal operation of the heating unit control system of the heat exchanger station of the power plant, the water inlet to the glycol solution heating equipment needs to be controlled by its own PLC, including the relevant valves, pumps, sensors, flow collection and all other related control and data acquisition. External devices can read unit data through RS485 serial communication. The touch screen displays the heating supply/return glycol solution pressure, heating supply glycol solution temperature, the primary side of the electric control valve opening, pumps, solenoid valves and other switching status, and a variety of alarm information. Among them, the information of pressure, temperature and alarm can be stored for 1 year of operation data. Touch display of the heat exchanger unit system operation status diagram, various pressure and temperature operation curves. Various temperature, pressure and other set values can be set through the touch screen.
Key words: PLC,HMI,PID,VFD
