Capacity variation of two capacitance of measuring membrance is also proportion to pressure . by amplified circuit the would be linearly converted to 420 ma dc two wire system current voltage or digital hart output signal high - speed addressable remote sender data road 测量膜片的两电容固定极板的被放大电路线性地转换成420ma dc的二线制电流电压或数字hart高速可寻址远程发送器数据公路输出信号。