The PC, PCI-6221 interface card of NI company, NI signal disposal module （strain, RTD, TC, etc.） are used as the hardware platform. CSY-2000 C sensor and measurement ＆ control technology experiment platform are used as the measurement and control object. The LabVIEW8.2 is used as the software development platform. The automobile digital virtual instrument simulator is designed. The information of date/time, total mileage, the current speed, speed, temperature, oil in the tank can be displayed. The automobile meter calibration is implemented.

This paper introduced a kind of STC89C52 as the core design of the intelligent temperature transmitter,it used AD7715 for input signal processing and A/D transformation,AD421 completed D/A transformation and V/A transformation.It will reflect the temperature changes in a linear modulation signal into voltage signal,the current signal is converted into the corresponding(from 0 to 16 mA),plus the system static current 4 mA and realize from 4 mA to 20 mA the analog output,apply to lots of industrial heat resistance and thermocouple temperature sensor.This paper analyzed the system design theory basis and the hardware and software design.The intelligent temperature transmitter to achieve automatic range conversion,automatic zero adjustment and automatic calibration,and other functions,make system has the function of intelligent measuring instruments,and has RS-232 communication function.The whole circuit design is simple,with high accuracy,good stability and low cost.