[Abstract] Position servo systems, with fast and high-precision tracking as their primary objective, are one of the main control methods widely used in high-precision position control. Their drive signal is a pulse signal representing the position command. This paper introduces a scheme and software development for driving a packaging printing position servo system using the MINAS series of fully digital AC servo drives as the execution structure. The high-speed counter and PTO integrated pulse output function of the S7 200CPU214/DC are utilized. Keywords: Position control; AC servo system; Driver; Packaging printing press; Color mark sensor. In today's era of rapid scientific and technological development, to meet the demands of modern consumers for exquisite product packaging, the requirements for high automation and precise position tracking in packaging printing production lines are increasingly stringent. Applying various advanced technologies to packaging lines to achieve high automation and high efficiency in packaging printing production lines has become urgent. Fully digital AC/DC frequency conversion servo drives offer high control precision, fast response speed, and strong anti-interference capabilities. Applying it to the packaging line to form a closed-loop position controller is of great significance. It solves many problems in packaging and printing, such as the reliance on manual initial positioning and adjustment, complex operation, large positioning error, slow dynamic cycle, serious misalignment during movement, and difficulty in color matching. 1 Principle characteristics and operation of MINAS series fully digital AC servo system: We use the Panasonic MSD fully digital vector control system with a variable frequency drive. It utilizes PWM pulse width modulation variable frequency, has powerful performance, and is suitable for high-performance position controllers. It has 38 parameter settings and 6 control modes, among which the pulse train position control is the most unique because it uses a pulse signal with a certain rate as the input signal representing the position command. In complex working environments, it has higher accuracy and stronger anti-interference ability than analog speed input signals. 1.1 System composition Figure 1 shows the schematic diagram of the PWM type vector control variable frequency modulation system of IGBT rectifier transformer. The frequency given signal is used as the input of the given integrator after soft start. The output of the given integrator controls the frequency and forward and reverse rotation respectively. The function generator is set up to keep the air gap magnetic flux of the motor constant at low frequencies and to compensate for the influence of the stator resistance voltage drop. The inverter output voltage control adopts a voltage and current dual-loop control system. The frequency conversion control circuit adopts an absolute value amplifier. This is because the given signal can be positive or negative, while the PWM section requires a control signal with constant polarity. The frequency conversion control signal controls the three-phase sine wave generator to generate a three-phase sine wave with variable frequency. The PWM modulation signal is generated by comparing the constant amplitude frequency conversion sine wave with the triangular wave. According to the positive and negative of the given signal, the phase sequence is changed by the logic switching circuit to realize the forward and reverse control. [align=center] Figure 1 Schematic diagram of PWM type frequency conversion speed control system[/align] 1.2 Features (1) The MINAS series has various parameters that can be used to adjust the characteristics of the system. Correctly setting these parameters can make the system reach the best motion state. (2) It has monitoring functions such as deviation pulse number monitoring, motor speed monitoring, and motor torque monitoring. (3) Display the input/output control status of CNI. /F. (4) Display the cause of the fault in the history. (5) It can be monitored and operated by computer MSD. 1.3 Operation of pulse train position control error (1) In position control mode, release the deviation count clear signal CL and release the pulse command prohibition signal INH, and the motor is in SBRVO-LOCK state. (2) Set parameter NO.2 to 0. This mode is position (pulse train) control mode. (3) Set parameter NO.29 to 1. The motor speed is proportional to the input pulse frequency f*p25/p26 p27=2500*4*n/60. (4) Set the speed feedforward coefficient to the minimum through parameter 21. (5) Set the value of parameter 03 to a larger value until oscillation occurs. (6) Set the position loop gain parameter 20 to a larger value until oscillation occurs. (7) Set the position loop gain parameter to a larger value until oscillation occurs. Set the speed loop integral time constant parameter 04 to a smaller value. The smaller the value, the greater the difference between the position deviation value. 2. Introduction and Scheme Design of the Color Printing Automation System The system consists of a PC, an S7-200 programmable controller, and an MSD variable drive system as its control core. Its structure is shown in Figure 2. [align=center] Figure 2 Hardware Structure Diagram of the Control System[/align] 2.1 Control Principle The entire transmission system initially uses a rotary encoder mounted on the shaft end. As the transmission system operates, the encoder generates continuous pulse signals, i.e., N pulses per revolution. Based on the roller length, the number of pulses equivalent to 20 mm can be calculated. This pulse signal serves as the input given signal. Each color roller is equipped with a color mark sensor, which can detect color marks on the printed material. The detected color mark signal is then converted into an electrical pulse signal and fed back to the PIC high-speed counter. The software compares, analyzes, calculates, and logically judges the signal before outputting a control quantity to the actuator, adjusting the relative position of the color rollers and eliminating printing misalignment. In color printing, the rotation angle of the printing plate cylinder is generally changed to achieve the purpose of adjusting the printing position. Its closed-loop control is shown in Figure 3. [align=center]Figure 3 Control Principle Block Diagram[/align] According to a report from the Tokushima Prefectural Fruit Tree Experiment Station in Japan (Akai, 1984), Hayward fruits harvested on November 15th, sealed with 0.03 mm plastic film and using vermiculite saturated with potassium permanganate solution as an ethylene absorbent, could be stored at low temperatures for more than 182 days after harvest. However, when stored at 5°C alone, many rotten and overripe fruits appeared after only 154 days. This shows that even under low-temperature storage conditions, the effect of ethylene absorbents is significant. 3. Conclusion In summary, we believe that the most economical and effective method for preserving kiwifruit is to use: corrugated cardboard boxes + plastic film + (preservative materials) + low-temperature treatment. This addresses four key factors affecting kiwifruit preservation: temperature (which can be controlled by a low-temperature storage facility), humidity and gas environment (which can be addressed by suitable plastic film), and preservative materials (such as vermiculite) (which can remove volatile substances). Of course, kiwifruit preservation packaging technology has a relatively short history, and many issues still need further research. However, the advantages of preservation packaging are obvious: it can significantly reduce losses during the distribution process, improve the value and quality of kiwifruit, and shift from concentrated market supply to balanced market supply, meeting people's needs at different times.