Research And Design Of Gas Boiler Control System

With the continuous improvement of the level of industrialization, gas boiler hasbeen widely used. Limited to the defects such as low stability, weak security and nothigh combustion efficiency, conventional gas boiler control system has been not meetthe need of practical projects. Hence, improving the automation level of gas boilercontrol system and combustion efficiency become the mainly development tendencyof gas boiler system. Under this background, this paper designs a gas boiler controlsystem which can adjust its combustion ratio.Firstly, this paper not only introduces structure and functions of key parts of gasboiler system, but also analyzes the operational principle of the exhaust gas oxygensensor. This paper designs combustion ratio control system based on thecharacteristics of oxygen sensor air-fuel ratio. Meanwhile, in order to meet the needsof water temperature adjustment and water flow rate control, this paper designs a hotwater supply control system of gas boiler. Those two systems are commonlycomposing the control system of gas boiler.Secondly, with taking into full account the security and combustion efficiency,hardware and software of the gas fired boiler control system are designed. Hardwaresystem is using embedded system as core. This paper designs a minimum system andperipheral circuits based on STM32. And the peripheral circuits include some keymodules such as wide domain oxygen sensor acquisition circuit, the temperaturesampling circuit and isolation power supply circuit. For the software designs, thispaper chose RT-thread operator system as the main system after analyzing the needs.This paper divides the software system into two modules, boiler combustionclosed-loop control module and water temperature closed-loop control module,according to their function in the gas boiler system. And then designs those twosub-task modules in detail.Furthermore, in order to make it convenient to operate and protect the workers,this article designs a remote monitoring system based on PC. This remote monitoringsystem is based on VC6.0MFC package library. The upper computer and lowercomputer establish communication using MODBUS protocol. It chose Access datamanagement system as practical data management system. Remote monitoring systemcan divide into three layers, view layer, database layer and communication layer. View layer is used to interact with users, database layer is used to record data andquery data, communication layer is used to communication between upper computerand lower computer.