Abstract : This paper introduces the relevant technologies of computer-frequency converter communication and analyzes a new method of computer-controlled frequency converter through examples. Keywords : Frequency converter; serial communication; RS485 Frequency converters are widely used in industrial fields. Variable frequency speed regulation is one of the development directions of electrical automation. There are three main control methods for frequency converters: First, operation via the frequency converter panel, which changes the output frequency, acceleration/deceleration time, frequency change rate, and other parameters through the operation panel. Second, control via the frequency converter terminals, which changes the state and output frequency of the frequency converter by changing the on/off state combination of the terminals. Common methods include control circuits composed of relays or PLC control. Third, inputting 0-10V or 4-20mA signals at the analog input terminals of the frequency converter, and controlling the output frequency of the frequency converter by changing the magnitude of the input analog signal. Fourth, control via the communication port (RS232 or RS485) of the frequency converter. The increase in computer speed and storage capacity has made it possible for microcomputers to control frequency converters. Meanwhile, the computer's functions in logical reasoning, judgment, recognition, and decision-making can undertake control work according to a certain control law, providing conditions for realizing intelligent control in the system. This is the current advantage of microcomputer control over other control methods. Furthermore, the reduced cost of computer use and the convenience of its monitoring and maintenance have also prompted its entry into the field of variable frequency speed control and its gradual replacement of other control equipment. How to perform control is the focus of this paper. 1 Interface and Standard Conversion To control the operating status of the frequency converter, the microcomputer should send real-time control signals to the corresponding frequency converter, so real-time communication between the field and the computer is necessary. A serial communication port is used, and data communication is performed through a converter. This communication is easy to implement, low in cost, and has high reliability and practicality. Data communication via the serial communication port uses RS-232. This communication standard cannot be used for long-distance communication. Under normal transmission rates, using ordinary cables, if the transmission symbol distortion does not exceed 4%, the maximum transmission distance is 15m. If an optoelectronic coupler is used on the serial port, the communication distance can reach several hundred meters. In industrial settings, typical communication distances exceed 100 meters, and in some cases, can reach several kilometers. Therefore, direct serial communication is not feasible for data exchange. [b][align=center]For more details, please click: Computer Control of Frequency Converters[/align][/b]