Abstract : This paper briefly describes the design and application effect of the speed control system modification for the M1380 cylindrical grinding machine. Based on the actual situation of the No. 4 Rolling Mill Workshop of the Second Steel Rolling Plant, the speed control system of the grinding machine was modified, leveraging the advantages of frequency converters (energy saving and stepless speed regulation) and the debuggability of PIE programs. Keywords : M1380 cylindrical grinding machine, frequency converter, speed control, PLC, speed control system design, application effect 1 Overview The M1380 cylindrical grinding machine in the No. 4 Rolling Mill Workshop of Changte Company is a product from the 1960s and is an important piece of equipment in the workshop. This grinding machine performs precision grinding on the rolls used in the steel rolling production of the workshop. The table movement and workpiece movement of the M1380 cylindrical grinding machine are driven by an AC magnetic amplifier. Due to the aging of electrical components after many years of use, the original shortcomings of the speed control system have gradually become apparent. With the gradual increase in output and the production of specialty steel in the No. 4 Rolling Mill, the modification of the speed control system of the M1380 cylindrical grinding machine is urgently needed. From November to December, we modified the speed control system of the M1380 cylindrical grinding machine and optimized it using various methods to achieve fully automatic control and reduce operator workload. The working principle of the modified system is shown in Figure 1. The modified M1380 cylindrical grinding machine speed control system adopts AC speed regulation. The table movement and workpiece movement are both driven by AC motors, powered by frequency converters to achieve stepless speed regulation. Adjustable resistors on the external main control panel provide speed signals to the frequency converter, while the motor rotation direction and start signals are provided externally to the frequency converter. All control signals are processed by a PLC, which then controls contactors, solenoid valves, and indicator lights. The table movement is controlled by limit signals, enabling free movement and free left and right movement, and allowing the table movement motor to operate at a low speed (72 rpm), meeting the requirements of the M1380 cylindrical grinding machine in the "correction" state. [b][align=center]For details, please click: M1380 Cylindrical Grinding Machine Speed ​​Control System Retrofit Design[/align][/b]