The weight of the packed items obtained by the weighing machine is compared with the normal weight. If the deviation exceeds the allowable range, the sorting machine will judge based on the set value and the conclusion is that there are missing items in the packing. The PLC will give a signal to drive the removal device to remove the packed items from the production line. The main basis for the sorting machine to determine the absence of items is the moving average value. The moving average value refers to the average weight of the recent several boxes of the same brand (the specific number of boxes can be set by the operator). During the operation of the sorting machine, the weighing machine will compare the packed weight obtained with the latest moving average value. If the difference between the packed actual weight and the moving average value is greater than the set weight of the absence of items, it is judged that there is an absence of items in the packing. The sorting machine will automatically remove the box. The electrical control part of the sorting machine mainly consists of the absence removal device control and the sound and light alarm control. The sound and light alarm includes the sound and light alarm when there is an absence of items in the packed box and the sound and light alarm when there is an absence of items in the packed box. When the sorting machine detects an absence of items in the packed box or a lack of items, the sorting machine software automatically triggers an electrical signal through the serial port of the PLC system, causing the intermediate relay to close, thereby enabling the pneumatic electromagnetic valve and the sound and light alarm to work.

The electrical control part of the automatic sorter mainly consists of the absence removal device control and the sound and light alarm control. The sound and light alarm includes the sound and light alarm when there is an absence of items in the packed box and the sound and light alarm when there is an absence of items in the packed box. When the sorting machine detects an absence of items in the packed box or a lack of items, the sorting machine software triggers an electrical signal through the serial port of the PLC system, causing the intermediate relay to close, thereby enabling the pneumatic electromagnetic valve and the sound and light alarm to work.

The automatic sorter tracks the boxes on the conveyor chain of the electronic scale and collects the information processed by the reader. It conducts summary and analysis and assigns the results to the boxes. When the box reaches the rejecter, the non-conforming product is rejected. The box runs on the conveyor belt and first triggers the front side wall photoelectric sensor. A structure array is used to record the current value of the reader of the photoelectric sensor and the weight information of the front wall sorting. The photoelectric sensor triggers to record the current value of the reader, and then subtracts the pulse distance between the photoelectric sensor on the front wall and the photoelectric sensor on the box from the current value of the reader. Then, within a tolerance range, it searches for the value of the reader in the structure array on the front side wall to find the record of the weight information of the front wall sorting of this box, copies it to the structure array of the box, and records the weight information of the box sorting. If this box is not found in the structure array on the front side wall, it is considered to be an extra box, possibly due to excessive sliding or being inserted by human. This box will be recorded as an unqualified box. Similarly, the bottom photoelectric sensor triggers to check the structure array of the box, the rear wall photoelectric sensor triggers to check the structure array of the bottom of the box, and the reject photoelectric sensor triggers to check the structure array of the rear wall. When the structure array of the reject photoelectric sensor is reached, all the information triggered by the photoelectric sensor and the weight information of the front wall, the box, the bottom of the box, and the rear wall sorting is collected. By monitoring the current value of the reader and the information of the reject structure array, it is decided whether to activate the rejecter to remove the box.

The sorting machine is controlled according to the set feeding amounts of high, medium and low materials. The digital signals from the three sets of digital weighing devices and a speed sensor are sent to the PLC system respectively. The actual feeding amount signals of the three materials are directly compared with the set values and automatically adjust the weight of the box layer to ensure the set feeding amounts of the three materials. When the box is fed simultaneously, the digital signals from the three sets of digital weighing devices and a speed sensor are sent to the weighing instrument and the PLC system. The PLC system processes and calculates the three-way detected weighing (weight) digital signals and the speed pulse signal of the one speed sensor. Through integration calculation, the actual mass signal data of the three materials is directly compared with the set weight value. The weighing instrument issues a weight difference instruction, which is driven by pneumatic or motor to automatically adjust the weight sorting function at the box, so as to adjust the actual weight range of the three boxes in the sorting to the qualified and unqualified areas.

The control system of the weighing and detection machine consists of a frequency converter, an actuating motor, a control device and a load current detection. The control device is composed of a programmable logic controller (PLC), A/D and D/A conversion modules, etc. Among them, the frequency converter consists of a speed control system and a program parameter controller. The control device is composed of a PLC, A/D and D/A conversion modules, etc. The load current signal comes from the current feedback signal of each drive sorter frequency converter. The weighing conveyor is mostly driven by a double drum or multiple drum, and each driving drum is driven by a single motor. The PLC can achieve power balance, start signal setting, speed control and setting, communication with other controllers, data acquisition and centralized control functions. Through dynamic load prediction, the sorter can perform real-time frequency speed regulation according to the load size, allowing the sorter to operate at the maximum load state. The PLC collects the load current signals of the drive motors of the current and previous level weighing conveyors through the A/D module (the current signal of the frequency speed regulation device), processes and calculates them through the control software, and outputs the control frequency signal through the D/A module to control the frequency of the frequency converter to drive the weighing inspection machine, completing the automatic frequency speed regulation control of the belt transportation system. That is, when the sorter's intelligent control system is operating normally, when the load increases, the sorter accelerates quickly and runs at the desired speed, stabilizing after reaching the desired speed. When the load decreases, the sorter decelerates quickly and stabilizes after reaching the desired speed. When the load is empty, the sorter operates at the lowest speed.

The sorter mainly consists of the box input conveyor, barcode reader, dynamic weighing device for box packing, photoelectric switch, pneumatic solenoid valve rejection device, sound and light alarm, output conveyor, rejection box storage platform and PLC system, etc. The paper boxes to be inspected are sent into the dynamic weighing device through the input conveyor, and the input recognition/input edge trigger counter, output comparator, pulse width modulation and other functions are used for missing item detection. The barcode reader is used to track and locate the paper boxes throughout the process. It is required that the sorter must read the value of the barcode reader quickly and accurately. The PLC is used for control, and the control program is programmed using an electronic scale to solve the problems of signal reception lag and insufficient timeliness of reading the barcode reader. Finally, based on the detection result, the paper boxes are sent to the corresponding next production line. The specific functions of each part are as follows:

1. The input conveyor is used to convey the paper boxes to be inspected.

2. The barcode reader reads the information of the box shape code and transmits the box shape code information (including brand, specification, production line, etc.) to the PLC system for data processing. It is also used for the sorter to detect whether the box shape code of the box packing is intact.

3. The first photoelectric switch is used to clear the previous data of the weighing scale, and the second photoelectric switch is used to refresh the current weight information of the paper box and trigger a signal synchronously, so that the data acquisition card sends the current weight information to the PLC system.

4. The dynamic weighing system is used to weigh the current box packing weight information and display the weight information through the weight display device.

5. The missing item rejection device uses pneumatic solenoid valves. When the sorter determines that the box packing is missing, it automatically rejects the box to the rejection box storage platform.

6. The weighing conveyor is used to convey the inspected qualified finished material boxes.

7. The PLC system performs data processing and displays the interface of the sorter, and based on the sorter's judgment result, sends sound and light alarm signals and rejection signals in the case of missing or incomplete items.

The data acquisition of the sorter is divided into two parts. The piece shape code information acquisition is transmitted through the piece shape code reader to the PLC system via RS-232 communication information for use by the sorter for data processing; the weight data acquisition uses a weighing instrument. The sorting scale first sends the real-time weight information to the weighing instrument, and the weighing machine software collects the weight data from the weighing instrument through the serial port of the PLC system. The inspection machine software first reads the relevant data (including the latest moving average value, shortage setting value, maximum setting value, and statistics related to production volume, etc.) of the brand from the database based on the collected form code information for each item. Then, it compares the moving average value with the real-time weight data collected. If the difference is greater than the set shortage weight, the sorting machine will automatically remove this box for packing; if the difference is within the allowable range, the inspection machine will store the information of this packed box in the database and participate in the calculation of the latest moving average value. If the real-time weight of the current packed box is greater than the maximum value set by the sorting machine, the sorting machine will only give an indicator light alarm without removing it, still recording it in the database, but not participating in the calculation of the latest moving average value. This is to prevent the phenomenon of incorrect removal during subsequent box inspection due to an excessive packed box weight caused by some special reasons and a sharp increase in the moving average value.

In addition, if there is no certain form code in the packed box or if a certain form code is damaged, the sorting machine will give an audible and visual alarm before passing the weighing device. The collected weight data will not be stored in the database and will be removed, for on-site operators to verify and check to ensure a 100% qualification rate at the time of leaving the factory. In summary, by using the data processing software designed for this sorting machine, the following functions can be achieved:

1. Determine whether the packed box weight is within the allowable range of the qualified packed box standard weight. The moving average value can adjust the packed box standard weight dynamically according to the actual production situation.

2. Display real-time weight data, standard weight, and relevant product information, as well as statistics for the day, shift, and current brand. It can also manually modify the product standard information.

3. Archive relevant data and can query and manage production data, removal data by shift, date, and brand, and generate corresponding reports as needed.