基于USB接口的全自动热量计的设计及实现

Design and implementation of automatic isoperibol calorimeter based on USB interface

根据全自动热量计的具体特点和功能要求,借鉴基于PCI总线热量计研究经验,结合最新的温度测量与控制技术,完成了一种以CY7C68013为主控芯片的全自动热量计的研制与开发。介绍了系统软、硬件的实现方法,分析了影响内筒温升测量精度的主要因素,列举了保证内筒温升测量精度的具体措施。该仪器由主机应用程序通过USB接口控制,实现了即插即用及操作自动化,内筒温度计分辨率高于0.001℃,热容量实验相对标准偏差小于0.1%,热值误差小于30J/g。实际应用结果表明,该仪器易于操作,实验结果准确可靠。

In view of the widely used bomb calorimeters based on PCI or ISA bus, automatic calorimeter based on USB interface provides a better solution on performance, operation and expansibility. Therefore, a new calorimeter based on CY7C68013 was developed, which has the main features such as high resolution temperature measurement （measurement range： 15 -28 ℃, temperature resolution： 0. 001℃）, using a high resolution platinum resistance thermometer, full diagnosis for electronic and mechanical systems, as well as automated communication control and operation. The instrument is calibrated by burning certified benzoic acid to determine a constant called ＇ water equivalent＇ , and the experimental results from five calibrations are below 0.1% RSD. The combustion heat of the tested samples under standard conditions is calculated based on the observed temperature rise while taking account of the heat loss, and the calorific error is below 30 J/g. This instrument has been proved to be reliable, accurate and easy to operate in many industry factories.