一种新颖的电阻应变式两线制称重变送器设计

针对常用的电阻应变电桥式称重传感器输出电压信号变化极为微小(若干毫伏)、零位误差较大(与输出变化量相当,甚至大于输出电压变化量),不便于转换和传输的问题,为了将电阻应变电桥式称重传感器信号转换为两线制4~20m A电流信号进行输出,采用基于仪表放大器AD627和电流转换器XTR105的模拟电路转换方案,对信号进行放大、零位偏差补偿。通过V/I转换器,把电压信号转换成电流输出信号,有利于长距离传输。详细介绍了变送器的工作原理和硬件电路设计。通过测试实验验证了变送器的测量特性。

Design of New Two-wire Resistance Strain Transmitter for Weight Measurement

Considering the tiny change(several millivolts)in output voltage signals,obvious zero offset(equal to or greater than the output voltage)and inconvenience in conversion and transmission of the commonly-used resistance strain bridge-type weighing sensor,and for purpose of converting its output signals to 4~20mA current signals with a two-wire output form,a AD627 instrument amplifier and XTR105 current converter-based analog circuit conversion scheme was proposed to magnify signals and implement zero offset compensation;meanwhile,through V/I converter,it has voltage signals converted into current output signals for long-distance transmission.The working principle of the transmitter and the design scheme of the hardware circuit were introduced in detail.The test results verify the measuring characteristics of this transmitter.