Abstract: Remote real-time monitoring, automatic protection, and automatic data recording of various parameters of an air compressor unit were achieved using EVC. The structure, working principle, and software/hardware configuration of the control system are discussed. Keywords: Air compressor, touch screen, industrial computer, remote monitoring, frequency converter. Yancheng Baling Chemical Fiber Plant has two air compressors: one is a 185kW Sullair 24KT air compressor from the USA, and the other is a 75kW domestic air compressor as a backup. The start-up and shutdown of the air compressors are scheduled according to production needs, and workers operate the corresponding switches, valves, and main motors in the required sequence to complete the start-up and shutdown process. Emergency shutdown is implemented when temperature, pressure, or motor rated current exceeds allowable values. The air compressors operate intermittently 24 hours a day, requiring continuous 24-hour monitoring by workers. The Sullair 24KT air compressor uses Y/D reduced-voltage starting, resulting in a large inrush current. The normal operating current is 400A, while the air compressor is in an unloaded state for 2/3 of the time, with a current of 200A. In addition, noise has a significant negative impact on the health of workers who operate air compressors for extended periods, often leading to operational errors and directly affecting production. Based on the above, the operation process of the air compressor was modified to be fully automatic using a frequency converter, and monitoring and alarm devices were installed in the remote control room, realizing unattended operation on-site and remote monitoring and alarm functions. [b]1 Air Compressor Working Principle and Control Signal Points 1.1 Air Compressor Working Principle[/b] As shown in Figure 1, the entire process of the Sullair compressor unit from the start of air volume to unloading is divided into three stages: 1) When the air consumption is less than the rated air supply of the unit, the pipeline pressure increases. This pressure overcomes the spring force of the pressure regulating valve, causing the pressure regulating valve to open and pushing the screw valve to rotate, opening the screw valve. At the same time, the bypass hole in the main housing is opened, allowing compressed air to flow back to the intake end of the rotor. The air delivery volume of the compressor unit decreases accordingly, and the power consumption also decreases. 2) When the air consumption is too low, the pipeline pressure continues to rise, while the screw valve is fully open. At this time, compressed air uses the same principle to activate the pressure regulator, and through the adjustment of the Sullair control valve, the inlet valve is gradually closed until it is completely closed. This operating condition is the regulating state. 3) When the screw valve is fully open and the inlet butterfly valve is fully closed, but the air supply is still too high, the pipeline pressure continues to rise and exceeds the rated working pressure. At this time, the unloading state is entered. [b][align=center]For details, please click: Application of EVC Touchscreen Industrial Computer in Air Compressor Unit Monitoring and Control System[/align][/b]