【摘要】 <正> 一、引言众所周知,在工业微机控制系统中,通常都必须应用模—数转换器(A/D)。但是,考虑到实际测量中常用的压力、温度等一次传感器,由于其输出仅为数毫伏到数十毫伏数量级的模拟电医信号,若采用目前市售的常规A/D集成片,就必须另加一只毫伏放大器和多路开关。这样,A/D集成片本身的多路开关实际上只能利用一路,这显然是不经济的。另外,若要使整个系统达到1％的精度,在选择精度为1％的传感器的同时,通常还必须使毫伏放更多还原

【Abstract】 A 3-BCD millivolt A/D converter with 40-channel multiplexer is intro duced. It is applicable to A/D Convertion of low analog signals produced by many first elements, for example, temperature transducer or pressure transducer etc. In order to improve system accuracy, the paper analyses the effect of paramters of the millivolt amplifier, and provides a method for auto-adjus ting zero drift of the amplifier. This converter is applied in the microprocessor monitor system of L3. 5-20/8-1 air press. In the system, the rate of data logging is about 24 point per second, the accuracy of the A/D converter is higher than 0.2％.更多还原