Research On Laser Emitter Module Of The Steel Plate Flatness Instrument Based On FPGA

For measuring the quality of steel plate,flatness is an important index,and it’s very important to obtain the information of flatness accurately in real time during the production of high quality steel plate.However,the production environment of hot rolled strip is bad,so it’s very difficult to detect flatness in the production process.In this paper,the research is located on the laser emitter module of the hot rolled strip flatness measuring instrument.In order to deal with the influence of the stability of the output performance of the laser emitter module on the flatness measurement results,a high stability control system based on FPGA is designed.Firstly,based on the analysis of the requirements of laser emitter module,the selection of key components is completed,the influence of the working current and temperature of the diode laser on the output characteristics of the laser emitting module is discussed,and then the design scheme of the laser emitting module control system based on FPGA for the hot rolled strip flatness measuring instrument is proposed.XC6LX16-2CSG324 FPGA chip is used as the system control core,and high stable output characteristics of diode laser are realized from two aspects of constant current drive and temperature control.Secondly,by deeply studying the driving mode and principle of semiconductor laser,the constant current driving circuit is designed,and the stability of the circuit is analyzed.Thirdly,the temperature control principle based on TEC is discussed,and the working principle and driving mode of TEC,NTC thermistor and TEC driving chip ADN8830 are analyzed.The temperature control circuit based on ADN8830 is designed.Finally,in ISE14.7 compiler environment,the logic design of FPGA is completed by used Verilog HDL.And the function of data transmission,data cache,PID control,LCD display and the communication of computer are realized by this FPGA logic design.The experimental results show that the driving current of the laser can be adjusted continuously from 0 to 100 mA,and the current stability can reach 0.014%,the stability of the output optical power is 0.205%,which meets the requirements of the system.