基于虚拟仪器技术的薄层干燥实验系统

随着计算机技术的发展,基于标准个人计算机平台的虚拟仪器技术正成为测试与控制领域的重要应用工具。结合薄层干燥实验要求,给出了一种增量式PID控制算法,根据此控制算法和脉宽调制法,采用虚拟仪器技术LabVIEW软件开发平台,开发了一种实用的基于虚拟仪器技术的薄层干燥实验系统。对实验台干燥温度实行自动控制,控制精度为±0.5℃;通过间歇自动称量样品的质量,实现对样品水分、降水率等的自动监测;热风温度、样品质量、样品水分、样品降水率、尾气温度、尾气湿度等以图表实时显示,并以电子表格存储。实验表明,该系统具有自动化程度高、实验操作简单、测试项目多、工作界面友好、数据处理分析功能强,测试精度高等优点。

Thin-Layer Drying Experimental System Based on Virtual Instruments

Virtual Instrument(VI) is becoming a popular tool in measurement, test and automation owing to fast development of computer platform. In this paper, according to the process demand of thin-layer drying, a unique thin-layer drying experimental system based on the incremental PID control algorithm and pulse width modulation(PWM) is developed using virtual instrument software-LabVIEW. The precision of controlling temperature is ±0.5℃; sample moisture and moisture removal rate are auto-supervised through acquiring the sample mass intermittently; drying air temperature and humidity, exhaust air temperature and humidity, sample mass, and moisture removal rate etc. are shown as chart in time and stored in Microsoft Excel spreadsheet file for processing. Practical application of this system shows that its automaticity is high, the experimental operation is agile, the user interface is friendly, the data processing and analyzing functions are powerful and the measurement results are precise.