The Research On The Signal Simulator Of Meteorological Elements

The technology of automatic weather station (AWS) developed rapidly in recent years, and has been applied widely in military and civil affairs. In order to ensure the accuracy of AWS’s observation, it is of great practical significance to research the simulator of meteorologic elements, which has enough precision, can simulate various meteorological elements sensor signal, can calibrate the data collector and can evaluate the errors of data collection rationed.This article designs a system for simulate the signals of meteorologic elements with MSP430singlechip machine, CPLD chip, and the analog circuit. Besides, the PC software is developed by Delphi environment and Access database. It achieved the functions of inspect the AWS data collection and judge the status of meteorologic elements sensors.On the basis of researching and analysising the principle of automatic weather station, through a combination of the feature of meteorological sensor, the overall design of signal simulator system is put forward with a consider of the requirements of data collection. Finally, the scheme of subsystem design is disussed from the aspects of the function and characteristics.Within the designing of temperature channel, the high-precision variable resistor is realized by using the principle of ’the drain-source channel resistance of the junction field effect transistor is controlled by the gate-source voltage’. The performance of the variable resistor is analyzed by the derivation of the JFET current formula and scanning simulation of the PSpice circuit, and the method improving the nonlinear and the dynamic range of the JFET variable resistance is proposed. With a combination of the single-chip and the digital to analog converters, the hardware module of the programmable JFET variable resistor is designed. The schemel which make temperature channel and terminal to be adapted is proposed through analyzing different data collector’s temperature measurement circuit.During the subsystem design, the modular thought is concepted as the main line. By using anti-interference measures, the circuit is designed which referred to produce and receive analog signals come from sensors, including temperature, humidity, air pressure, precipitation rain fall, wind direction and wind speed.The target of simulating and testing the signal of eitht basic elements of meteorological sensor is realized ultimately, and the system has required the accuracy successfullly.In the respect of PC software, Delphi7.0is used to design the manage software with man-machine control and the Access database is used for the management of data and information. The software includes the modules of control centre system, information management and industrial products checking system. Specially, the module of control centre system is designed including the user interface, data management and communication system.The system of simulator designed in this paper has been inspected and tested in the terminal verificationg experiment.The experimental results shows that the simulator can simulate various signal of meteorological sensor, and able to inspecte main data collector and sensor.The system is turned to be stable and reliable, highly precision and meets the design requirement.