Abstract : This paper introduces a method for analog control of a VFD-A frequency converter using the analog output function of the ACL-8112 data acquisition card. The creation of the dynamic link library and the operation process of the data acquisition card are explained in detail. A dynamic link library (DLL) is developed using VC++ to implement write operations on the ACL-8112 data acquisition card. Keywords : Frequency converter; Data acquisition card; Dynamic link library In the past decade, with the rapid development of power electronics, computer technology, and automatic control technology, electrical drive technology has faced a historic revolution: AC speed regulation replacing DC speed regulation and computer control technology replacing analog control technology. In modern industrial production, AC variable frequency speed regulation technology has been increasingly widely used. 1 Current Application Status of Frequency Converters Variable frequency speed regulation, with its excellent speed regulation and braking performance, high efficiency, high power factor, and energy-saving effect, is recognized both domestically and internationally as the most promising speed regulation method. Currently, AC speed regulation technology has covered all industrial fields, and AC motor variable frequency speed regulation technology is a major means to achieve high quality, high output, low power consumption, and promote technological progress in today's industrial production. In my country, 60% of electricity generation is consumed by electric motors; therefore, research on AC variable frequency speed control is of great significance. Overall, my country's electrical drive technology lags behind international advanced levels by approximately 115 years. In areas such as high-power AC-AC frequency conversion and commutatorless motor drives, only a few domestic research institutions have the capability to manufacture these technologies, and there is also a considerable gap in digitalization and system reliability compared to foreign countries. Therefore, promoting my country's electrical drive technology is an imperative task. In recent years, with the advancement and development of power electronics technology and power electronic semiconductor devices, variable frequency speed control technology has made significant progress. Variable frequency drives, with their high speed control accuracy, fast response speed, comprehensive protection functions, strong overload capacity, significant energy savings, and convenient use and maintenance, have been gradually promoted and popularized in my country. As a high-tech, fundamental, and energy-saving technology, variable frequency speed control technology has permeated all technical sectors of the economy. Therefore, research on AC variable frequency speed control technology will undoubtedly bring enormous social and economic benefits. [b][align=center]For details, please click: Application of ACL-8112HG Data Acquisition Card in VFD-A Inverter Control[/align][/b]