The Designing And Developing Of A New Float Level Gauge Calibrator

A float level gauge is an apparatus used to measure level, and is widely used in the production process. Its measurement accuracy searously impacts the results of process control. In the production ,it need to be calibrated regularly to keep the measurement accuracy in high level. In this paper, a float level gauge automatic calibrator, is designed and developed in a new method, to achieve higher accuracy .The calibrator has 4 analog input channels. It collects the signals from the sensor and float level gauge respectively. Signal from the 2-way switch output channel controls the stepper motor to produce pull. We utilize the four semi-double integral A/D converter, ICL7135, to proceed analog-digital conversion. After linearization, we can obtain the corresponding quantities. Then, the data can be transmited between the equipment and the upper monitor, through RS485 and RS232 Interfaces, in Modbus RTU transfer protocol. We can setup a variety of related functions through interacting with interface provided on Liquid crystal. Information and data is stored by I~2C Bus and SPI Bus. The system could work in a wide range from 9V to 36 V. Through DC-DC conversion, serval groups of isolated power are obtained for the digital, analog and the sensor respectively, to ensure the stable operation of the entire system.The calibrator in the paper achieve higher accuracy level, the accuracy level of signal measurement is±0.5‰, the rally accuracy level is±0.5‰, and the sensor's power supply accuracy level is±1‰.