The explosion-proof variable-frequency scale combines the functions of Electronic scale weighing, bucket disinfection, bucket transportation, quantitative filling, lid feeding and lidding. The large disc with continuous rotation operation controlled by the frequency converter uses the bucket positioning technology to control the feeding of the buckets. The entire circumference of the rotating disc is evenly divided into multiple groups, and each group has multiple barrels to be filled simultaneously. When the filling signal arrives, the multiple filling heads are controlled by the coordinated running mechanism of the rotating disc to descend to a certain depth in each of the multiple barrels, and at the same time, they run synchronously with the rotating disc and perform filling. When the quantitative filling is completed, the multiple filling heads are lifted by the cylinder mechanism to completely separate from the filling barrels and quickly swing back to the initial position, and wait to fill the next group of empty barrels. The filled barrels are transported to the lidding section for processing. Thus, the Filling system completes one cycle of operation. 

The quantitative scale uses two methods - PLC output and the setting of the weighing instrument - to control the feeding frequency. When the PLC outputs, the on-site frequency converter is controlled through the filling setting. When the operator selects the ratio setting on the operation screen, they only need to input the filling setting quantity to automatically calculate the feeding quantity for each scale, and then perform tracking adjustment based on this feeding quantity. The flow control of the electronic scale is carried out through the flow setting area on the screen. When setting the PID parameters of the electronic scale, according to the output frequency of the on-site frequency converter, the feeding quantity of the electronic scale is compared with the weighing value of the total transportation volume under the given frequency. Based on the difference, the flow of the filling gun is corrected. 

The electronic weighing platform is combined with a servo unit and servo motor. The weighing platform forms a highly adaptable and flexible servo control system to replace the cam feed and rapid swing functions. To reduce the power requirement of the system for the driver, lower the engineering cost and ensure that the system can drive the load to perform rapid acceleration/deceleration movements, the load transmission link adopts synchronous toothed belts driven by a step wheel reduction transmission device. The synchronous toothed belt reduction device has elastic and damping characteristics, which not only isolates vibrations but also reduces the rotational inertia of the load transferred to the motor, but also increases the order of the load transmission link and increases the control difficulty. 

The positioning tracking performance of the filling scale and its ability to suppress periodic interference signals are the essential guarantees for the horizontal position tracking system of the filling needle for the filling barrel, which is a prerequisite for achieving vertical filling. Due to the requirements of production efficiency and filling quality, the operating speed of the filling system is increasing, and the higher the horizontal position tracking accuracy, the smaller the diameter of the barrel to be filled, the higher the system tracking accuracy. In response to the actual situation where the horizontal position tracking system control algorithm of the fully automatic Filling machine needs to be simple, have good real-time performance and high accuracy, it is proposed to combine PID control with improved double repetition control, and utilize their respective advantages to form a composite control strategy based on double repetition control and PID control. The genetic algorithm is used to tune the PID parameters, and the PD (proportional and differential) link is introduced in each repetition controller channel.