Software Design Of Soot Concentration Online Monitoring System Based On Weighting Method

According to the standard of "The method on particulate detection and air pollutant sampling for fixed pollution source effluent",which is issued by China's Ministry of Environmental Protection in 2013,and aiming at the defects in the weighting method that is using in monitoring of soot concentration in China.The laboratory project team designed and implemented an on-line monitoring system based on the filter weighing method,and put it into the actual power plant for testing.This paper mainly completes the software design of the on-line monitoring system which based on the weighing method.Mainly including the following part:(1)The PLC control program design for system control unit.Through programming of S7-200 PLC to controlling the overall operation of the system process,to controlling the temperature,humidity,pressure and other industrial equipment,to controlling the analog's conversion and calculation which is produced of sensor,to realize free port communication function between PLC and STM32.(2)Embedded program design for weighing unit.Through programming ofthe STM32 microcontrollers to controlling the mechanical movement of the weighing unit,to controlling the electronic analysis microbalance,and to controlling the communication with PLC.(3)Drawing the interface of HMI unit.Using the Win CC configuration software to draw the interface of HMI,to display the system operating status and key parameters in real time,and to display the historical curve of the system key parameters,and to display the alarm of the system operation error and parameter exception,and to debug the system through the interface of HMI.(4)Design of equal flow sampling based on fuzzy algorithm.According to the demand of equal flow sampling,and the relationship between the frequency of frequency converter and the difference that between the measured flow rate and the sampling flow rate,this paper implement to control the equal velcity sampling based on fuzzy algorithm.So that the system sampling process can better adapt to the complex flue environment,and the system is more reasonable.Finally,putting the system into the field to test,and analysising the measured data scientifically,summarizing the factors that contribute to system errors and summarizing where the system needs to be improved.System make up the obvious defects that using weighing method to monitor soot concentration in china.The system has high degree of automation,and it can monitor the concentration of soot in unattended conditions.