I. Introduction Mineral wool sound-absorbing board is a new type of building decoration material that our company put into production last year. We introduced the most advanced Japanese complete set of automatic board production lines from the 1990s, which can simultaneously produce mineral wool sound-absorbing boards of different thicknesses, specifications, and colors. However, due to the high cost of the original Japanese packaging line equipment and the lack of such fully automatic board stacking packaging lines in China, our center developed this automatic packaging line, which has been put into use. This automatic packaging line is a successor to the automatic board production line. Since the finished mineral wool boards (specification: 300mm×600mm) are transported out of the drying kiln in two parallel lines, this automatic packaging line also has two independent diversion, flipping, and stacking systems. Finally, they are all brought together by the packaging section and then enter the sealing section to complete the packaging task. According to the process requirements, this packaging line should be able to achieve: (1) Automatic flipping, that is, flipping the first board and placing it on the second board so that the two boards are in contact with each other. (2) Automatic stacking, that is, stacking the boards of different specifications after flipping into a stack in different quantities. (3) Automatic packing, that is, the robotic arm places the stacked boards on the cardboard box, and after passing through this section, the stack of boards is automatically packaged and glued into a box. (4) Plastic sealing, that is, the packaged box is plastic sealed. II. Main equipment and control scheme of the control system This automatic packaging line is a typical logic sequence control production line with a large number of detection elements, complex logic relationships, and high difficulty in implementing actions. There are nearly 400 I/O points. In addition to the frequency converter, the controlled equipment also includes a single-axis AC servo system and a glue spraying system. Since the production line is long and the execution equipment is relatively independent and centralized, according to the principle that the equipment can be controlled nearby, three sub-control cabinets are set up in sections under the central control cabinet. The remote I/O system composed of OMRON-C200HG is used to complete the control scheme. The control system structure is shown in the figure: The above figure uses the Omron-RM201 master station unit to connect with three Omron-RT201 slave station units through the RS485 communication port. The servo system consists of an OHM ODC-1001 controller, a Panasonic DV80X driver, and a servo motor. The servo can be controlled directly by an input device (ODC-1001) or by the central control cabinet panel. It is controlled by two independent I/O units of the PLC. The glue spraying system has an independent glue temperature control circuit, and the control signal for the glue spraying solenoid valve is provided by the PLC. This automatic packaging line has the following functions: (1) full-line automatic operation; (2) independent automatic operation of each section; (3) local control of manual operation of field equipment; (4) each control cabinet is equipped with an emergency stop button, and the robot and servo motor are equipped with special emergency stop buttons. III. Control System Design The control system program design of this automatic packaging line uses OMRON SSS software to directly program with ladder diagrams, and conducts on-site debugging and program monitoring. After on-site debugging, the system can meet various working conditions on site and is extremely simple to operate. It can judge and analyze faults and human interference, and realize simple intelligent functions. This program adopts a modular design, allowing each work section to operate independently. Modules are linked and interlocked, enabling signal sharing during full-line or segmented automation. The following diagram shows the control logic for the packaging section of the packaging line: The servo motor's movement is controlled by the completion status of the three workstations. Upon initial power-up, the servo motor returns to its origin. Since there are no workpieces at any of the three workstations, the servo motor must proceed from the carton station, moving one workstation at a time. Once the carton station finishes picking up cardboard, the servo motor executes the program. When the servo motor stops, the carton station picks up another cardboard to complete its work, but it cannot move forward immediately. Only after the packing station's robotic arm has placed a stack of cards can the servo motor move to the next workstation. Then, the carton station picks up another cardboard, and the packing station places another stack. At this point, the servo motor must wait for the gluing station to finish gluing all the cartons before it can move forward again. Afterward, all three workstations operate simultaneously, and the servo motor continues working. The logic of this program is relatively complex; the key is to focus on the servo motor's forward movement. The SEUREST instruction was used in the initialization design of this section, proving convenient and effective. Several key issues need to be considered in this program design: ① The PLC power supply is only disconnected during major factory overhauls or prolonged periods of inactivity. At the end of each shift or during breaks, a soft shutdown is implemented on the control panel, leaving the PLC in RUN mode. The servo motor also only requires a soft shutdown. Therefore, the servo motor must be able to distinguish between a PLC power-off and restart or a soft shutdown followed by a restart. ② Since the servo motor's motion trajectory and the robot's motion plane are perpendicular, and they are controlled by two independent sub-control systems, two signals are necessary for the robot to extend: the energizing signal A of the lifting rotary cylinder and the servo program segment end signal B. When signal A is activated, it indicates that there is a board at this station, and the servo motor is waiting for completion signals from the other two stations; the servo motor is about to start. Even if signal B is activated at this time, the robot will not extend. When signal B is connected, it indicates that the servo machine has completed the program and can proceed with the operation at this station. When signal A is disconnected, since the servo machine is currently running, the plate can only be loaded at the loading station when both signals are simultaneously satisfied. ③ The three stations connected by the servo machine mostly use electromagnetically controlled cylinders for execution. Therefore, insufficient cylinder pressure, loose mechanical limits, and unexpected malfunctions will affect the completion of the work at this station, delaying the action time and leading to stacking, flipping, and blockages in the conveyor section. Therefore, the design can be based on cycle time, with time monitoring and fault alarms set for each cylinder that must be in position. The servo system consists of an OHM ODC-1001 and a Panasonic DV80X, using a teach-in programming control method. The OHM I/O signal interface has 48 terminals. We use an open-collector control method, leading the pulse output terminal, etc., to the CN I/F terminal of the DV80X using twisted-pair shielded cables to control pulse and pulse symbol input. Simultaneously, the program selection terminals CHA and CHB, along with the start signal, are connected to the PLC's output module as the servo's program selection channel signals. STANDBAY is selected as the servo program end signal and connected to the PLC's input module. When the PLC receives this signal, it can perform other actions on the production line. Additionally, a home return signal is output from the PLC, allowing the servo to return to the origin after executing the prescribed program due to negative tolerance. A reflective photoelectric switch is used for the home return signal, ensuring the total cumulative error is within -0.1mm, meeting accuracy requirements. Regarding the power supply selection, the servo's 24V power supply capacity cannot be too small and must be used separately from the PLC's 24V power supply to avoid interference. Therefore, the same consideration should be given to the PLC module selection; servo signals should be avoided from being mixed with other signals in the same module, and PLC modules with independent COM terminals should be given priority. The servo control program (INC programming) is as follows: STEP1 DIM = (0000.0000) STEP2 POS = +787.9800 OUT = OOOO SPEED = 100 SLOPE = 30 STEP3 POS = +42.00001 OUT = 0000 SPEED = 50 SLOPE = 30 STEP4 POS = +12 STEP7 STEP6 END STEP7 RTN STEP8 END The main equipment in the sealing section is a continuous resistance furnace. Its temperature control consists of two parts: an SR-73PID temperature controller and a solid-state voltage regulator (or a PAC03A three-phase voltage regulator). The temperature controller inputs an analog signal via a K-type thermocouple and outputs a 4-20VDC voltage to control three solid-state relays (SSRs) (or directly controls the PAC03A three-phase voltage regulator). Each SSR (or controller) drives several heating elements. The solid-state voltage regulator is controlled by a potentiometer, and each regulator also drives several heating elements. The overall control of the temperature controller and the solid-state voltage regulator is performed by a PLC. This allows for segmented full temperature control, segmented voltage regulation, and segmented direct start-up within the sealing furnace, maintaining the temperature at approximately 180℃ for sealing pre-packaged boxes. Other actions in this section, such as box pushing, sealing/cutting, and film placement, are also controlled by the PLC. IV. Conclusion Building panels are a popular new type of building decoration material. However, due to their structural characteristics—large area, small volume, easily damaged edges and corners, and fragile surface—the packaging of finished products has become a pressing issue. Currently, most building material companies in my country use manual packaging, which is labor-intensive for workers and does not guarantee the quality of finished products. Since our company implemented this automated packaging line, these problems have been largely solved, significantly improving the product qualification rate and reducing the number of production line workers by nearly three-quarters, receiving high praise from users.