The liquid-level automatic Filling machine is mainly composed of the main cabinet of the weighing instrument (PLC weighing module, 1/0 interface device, control buttons, warning lights, etc.), the feeding system, the discharging system, the cylinder system, the Electronic scale, the pneumatic system, the on-site control cabinet, etc. The electronic scale converts the actual weight into millivolt electrical signals and sends them to the weighing instrument. The weighing instrument converts the analog electrical signals into digital electrical signals and compares them with the set values on the panel. Through the PC, it outputs switch signals to control the coarse feeding and fine feeding mechanisms to perform fast or slow feeding or stop feeding, thereby completing the quantitative filling process. After the bucket is clamped by the cylinder mechanism, the material automatically fills the bucket on the electronic scale, fills it completely, then releases the bucket onto the cap press machine for cap pressing, thus completing the automatic weighing and filling process. The target quantity for filling should be set according to the filling volume. The actual set value is calculated based on the relevant values from the previous weighing. The difference between the previous full and empty weighing values is the actual output volume. The difference between the actual output volume and the previous actual set value is the compensation volume. The sum of this set value and the compensation volume is the actual set value for this time. This forms a loop to create a closed automatic compensation control system. 

The Liquid filling machine consists of two sets of weighing control devices: a two-way feeding system for the filling gun, two filling guns, a weighing instrument, a discharge gun, a contraction mechanism, and a touch screen. The bucket is used to store the materials to be weighed, and the weighing module installed at the bottom of the electronic scale is used to detect the mass of the materials in the bucket. The contraction mechanism can contract the filling gun according to the control signal, the weighing instrument is used for data collection, processing and control, and the touch screen with configuration software realizes real-time display of data, setting of system parameters, etc. The weighing filling machine adopts the method of decentralized weighing and decentralized control. The weighing error is distributed to the electronic scales participating in the weighing, the filling volume is completed jointly or alternately by the electronic scales, and the filling error comes from the electronic scales participating in the weighing. The control electronic scale value gives the filling quantity. When the program steps forward, the Weighing system starts working. When the actual weighing value is greater than the difference between the current weighing target value and the material filling advance amount, the filling stops. When the material filling is full, the material filling full signal is received. When there is a discharge request and the system has the conditions for discharging, the filling gun on the electronic scale automatically opens and starts discharging. When the actual weighing value is less than the material empty set value, the material empty signal is received. The electronic scale controls the filling gun to automatically close. During the discharging process, the difference between the discharging opening value and the discharging closing value is the actual filling volume, the valve drop value is the compensation value, and the sum of the compensation value and the filling volume is the actual setting value for the next time. When all the selected electronic scales have discharged the material, the program steps forward to the next weighing target value. The difference between the selected electronic scale's weighing target value and the material is 5% plus the original filling volume of the material. This can more accurately control the operation of the filling gun, forming a cycle, and the control becomes more precise with smaller errors, achieving automatic compensation of the weighing system. 

After setting the quantitative values, fast-in volume, medium-in volume, slow-in volume and other parameters through the touch screen, the system is started. Under the automatic filling control, the valves of the discharge port are fully opened to allow the materials to quickly enter the weighing bucket. At the same time, the material weight is converted into corresponding voltage signals by the weighing module and transmitted to the weighing instrument. The weighing instrument completes the amplification, filtering, A/D conversion and processing of the signals. The processed data, on the one hand, is transmitted to the touch screen for real-time display, and on the other hand, is compared for weighing, to determine whether the material quality in the bucket is greater than the parameters set on the touch screen. Based on the comparison results, the controller will combine the three-level feeding algorithm to output the control quantity to drive the actuator to control the valve closure, thereby changing the feeding speed. When the material weight in the weighing bucket plus the air drop amount reaches the quantitative value, the valve of the discharge port is closed. Then, the weighing instrument with an embedded touch screen sends a discharge request. Wait until the embedded touch screen gives a discharge signal, and finally execute the discharge. The quantitative weighing of the weighing instrument is completed. The entire weighing and unloading processes are controlled by the weighing instruments, and the coordination process of the two weighing instruments is controlled by the embedded touch screen.