Research On Supervisory Controlling System To Heat Exchanger Comprehensive Experiment Platform

As a most common unit operating equipment,shell-and-tube heat exchanger is the experimental subject of comprehensive experiment platform.Based on the platform,a variety of experimental projects can be accomplished,such as structure disassembly,heat transfer performance,process control,research and development of new type heat exchanger,and so on.Supervisory controlling system is important component of platform.This paper centers on the supervisory controlling system of comprehensive experiment platform.The main research contents are as follows:Firstly,this paper analyzed the functions of experimental platform and designed the overall monitoring system.To meet the demand of the platform and modular,monitoring and control system uses intelligent instrument as the controller with IPC and industrial control configuration software for the upper computer to build a typical structure of upper and lower structure.Based on intelligent instrument,three separate control circuits are built,to realize variable frequency pump flow control,silicon controlled temperature control,the independent control of the cold and hot water circulation system and the outlet temperature objects of the heat exchanger.Based on USB data acquisition card and Modbus data communication,PC can build I/O channels to obtain field data,send control command,build a complete computer directly control circuit.Secondly,this paper has carried out the heat transfer process calculation for the experimental platform system,and has carried on the selection of main equipment and testing control components of the system.Thirdly,in this paper,PC software system is developed,on the basis of the configuration environment of MCGS.The system constructs the process interface of real-time with abilities of real time curve,history curve,history data extraction,network interactions,etc.This paper mainly discusses Implementation of the system communication.The configuration environment gets the process parameters through data acquisition card of USB2010,and interacts with smart meters and frequency converter with the basis of the ModbusRTU agreements,obtaining field data,sending frequency control instruction,realizing the bidirectional data transmission.Fourthly,to run system debugging,and the control circuit of smart meters and related parameters of converter is optimized Settings.Based on the experimental platform,the heat exchanger heat transfer,SCR temperature control,variable frequency pump flow control and heat exchanger outlet temperature control and other experimental projects can be completed.At the same time,based on the MCGS configuration software and unified I/O channel,feedforward control,cascade control,and other forms of complex controls,and the combination control of temperature,flow rate,and other feedforward variables can be realized,which enriches experiment contents.