一个简单低成本的遥测相对湿度和温度的数据采集系统(英语原文与翻译).docVIP

A Simple Low Cost Data Acquisition System for Remote Sensing of Relative Humidity and Temperature Abstract: This paper presents a simple technique in combining analog circuit and digital circuit theory together with programming technique to control the hardware for remote sensing of temperature and relative humidity. The sensor circuit converts the relative humidity and temperature into an analog signal, which will then be applied, to a micro controller based data logger for storage purpose. The data is then transferred to the computer through RS232 standard serial port. The user interface program will be handling the data transfer between data logger and the computer as well as allowing the user to input some of the important parameters such as sampling interval and starting date and time for the logging operation. The system can perform in both real time and off line. Keywords: Relative humidity and temperature, data acquisition, remote sensing. 1: Introduction Sensing and recording both relative humidity and temperature play an important role in many industries. In pharmaceutical industry relative humidity control is critical in manufacturing of certain formulations which are moisture- sensitive (hygroscopic) such as vitamin tablets, and oral dehydration salt tablets. Granulating and packaging operations of certain tablets must be conducted in low- humidity environments (maximum 25% RH at 25) if the long-term stability of the tablets is to be maintained [I]. Polished metals, e.g. brasses bronzes, do not tarnish at 15% relative humidity or less when kept in the museum [2]. Relative humidity has to be maintained at stable levels to avoid extreme levels and wide fluctuations. Ideally, fluctuations in relative humidity should not exceed 3% in one hour, 5% in 24 hours. In the past, some analog device was used to record the relative humidity over a long period. However at present, electronic sensing and data acquisition proved to be better approach.