Firstly , the whole scheme of the transducer is designed , the transducer includes capacitance / voltage converting , ripple - control capacitor switching , magnify - multiple switching , a / d converting , singlechip , photoelectric isolation and rs - 485 serial communication , etc . the measurement of microcapacitor is the key technology of transducer 首先对变送器部分进行了整体的方案设计,变送器由电容/电压转换、纹波控制电容切换、放大倍数切换、 a / d转换、单片机、光电隔离和rs485串口通讯等几部分组成。