说明：  利用MSPd30F149 单片机和AIM21电流环芯片，通过简单的压频转换(多谐振荡器)电路实现了基于电客式差压 传感器的智能差压变送器设计。该设计的特点是利用压频转换电路取代了A／D模块，以极低的产品价格达到了较高的 系统测量精度。采用软件与硬件相结合的信号处理技术，实现了基于HART协议现场总线技术的差压模拟量的测量，通 过进一步采用CPLD器件的量化延时测频技术，将可以达到比传统A／D器件更高的压力测量精度。智能差压变送器；HART协议现场总线；MSP430F149；AIM21
(The use of MSPd30F149 chip microcontroller and AIM21 current loop, through a simple voltage to frequency converter (multi-harmonic oscillator) circuit based on power-off-type differential pressure sensor design of intelligent differential pressure transmitter. The design is characterized by the use of voltage to frequency converter circuit to replace the A/D module, a very low price to achieve a high system accuracy. Using a combination of software and hardware signal processing techniques to achieve an agreement based on the HART field bus technology differential analog measurements, using CPLD devices through further quantify the delay frequency measurement techniques, will be able to reach than the traditional A/D device is more high-pressure measurement accuracy. Smart differential pressure transmitter HART protocol field bus MSP430F149 AIM21)