Abstract: This paper mainly describes the application of EC20 PLC in a fully automatic steel pipe cutting machine. Through this application, the automation level of the equipment was enhanced, and the system's working efficiency and reliability were improved. Keywords: Emerson EC20, pipe cutting machine I. Overview This pipe cutting machine is mainly used for cutting various pipes in the electric heating tube industry, such as steel pipes, aluminum pipes, and iron pipes. The original control system used relays and limit switches, resulting in low output and the inability to automatically feed, clamp, and cut. The customer decided to adopt PLC control. To increase output, maintain the accuracy of sawing workpieces, reduce labor intensity, and reduce labor costs, the control system has functions such as automatic feeding, fixed length, automatic clamping, and automatic cutting; it can also set parameters and has advanced functions such as protection alarms. II. System Control Composition and Process Requirements This pipe cutting machine is only part of the steel pipe production line. In order to ensure the normal operation of other equipment on the production line during steel pipe cutting, there is a movable cutting platform that remains relatively stationary with respect to the steel pipe to complete the cutting. The following figure is a schematic diagram of steel pipe cutting: The pipe cutting machine has two control modes: manual and automatic. Manual operation is generally used for the first cut. The system cuts directly without considering the pipe length; subsequent cuts are the same as automatic. After the steel pipe moves to the platform, when it reaches the desired cutting length, the orange section in the diagram activates, the extended push rod returns, and the pneumatic clamping mechanism engages, clamping the steel pipe, which pushes the cutting platform along with it. Simultaneously, the green section in the diagram—the cutting machine "lowers down" to begin cutting. After cutting, it touches limit switch #2, causing the cutting machine to "raise its head" and the motor to stop. During and after cutting, the platform and steel pipe continue to move until the platform touches limit switch #3, releasing the clamping mechanism and stopping the platform from moving with the pipe. After a delay (usually 2-3 minutes), the orange section in the diagram pushes the platform back. During the return stroke, it touches limit switch #4, activating the tipping mechanism (not on this machine), and the cut pipe leaves the pipe cutter. After the platform returns, it touches limit switch #5, waiting for the next section of steel pipe to reach the required length. The cutting length of the steel pipe is set on the LED input/output device. An alarm is triggered when a thermal failure occurs during the cutting of the steel pipe. The PLC control scheme uses the Emerson EC20 series EC20-1410BRA module. [align=center] [/align] Application Summary: Using the Emerson EC20 series high-performance PLC brings the following benefits to customers: 1. Centralized and simple operation, sensitive, and easy maintenance. 2. Improved system stability and anti-interference capabilities after the equipment's automation level is increased. 3. Automatic clamping, tool feeding, material feeding, dimensional setting, fixed-number stop, and working measurement functions. 4. Increased work efficiency and output. 5. Automatic alarm.