全自动数字万用表的设计

Design of Full Automatic Digital Multimeter

基于单片机和可编程逻辑器件设计了全自动数字万用表电路,利用自行研制的复合表笔测试探头实现了根据被测试量自动读档和自动选定测量量程的功能。介绍了交流与直流、电压与电流、电量与非电量的自动识别原理以及测量功能与量程的自动切换原理,着重阐述了该表的结构组成框图和软硬件的设计。该数字万用表除一个可拨动或按动的电源开关、一个复合表笔的插槽和一个普通黑表笔的插孔外,无任何可利用的部件向数字万用表输入信息。实验测试结果表明,该表具有性能稳定、测量精度高、结构简单、使用方便、成本低等优点。

The design of the full automatic digital mnltimeter circuit is based on the mierocontroller unit and the programmable logic device. The function of this type of mnltimeter is to read the archives and choose the measure range automatically by the physical quantity which is to be measured. And the function is realized using the complex table pens as test probes that are self-developed. This paper not only describes the principle of automatic identification between the direct current and the alternating current, the voltage and the current, and the electric quantity and the non electric quantity, but also it shows you the principle of automatic switch between the measure function and the measure range. In this paper the architecture composition diagram about the muhimeter and the design of software and hardware are mainly discussed. The muhimeter only has a power switch that can be pressed, a slot for complex table pens and a jack for the general black table pen. And there are no other parts that can be used to input information to the digital muhimeter. It can be proved by tests that this multimeter has the advantages of stable performance, high accuracy, simple architecture, convenient use and low cost.