Abstract: This paper introduces the structure and principle of the sintering batching system, as well as the problems encountered in its application and their solutions. Keywords : Automatic batching, Automatic control Introduction As we all know, the batching system of a sintering plant is the source of the entire sintering production. It is responsible for supplying the mixed materials to all sintering machines. If the batching system encounters a problem, the entire sintering production will be forced to stop. Moreover, the calculations of the batching system must be accurate because there are many types of sintering raw materials, and the composition of the batching changes with the supply channels. The proportion of each batching material will also change according to the production requirements. In addition, during the production process, changes in the viscosity, specific gravity, particle size of the material, as well as the temperature and humidity of the environment, will seriously affect the accuracy of the feeding. Therefore, the batching system is crucial to improving the quality of sinter. I. Working Principle of the Batching System 1. Batching Principle In the metallurgical industry, the stability of the composition of sinter plays a very important role in the ironmaking process. The accuracy of the proportions directly affects the quality of sinter and ironmaking. In traditional sintering batching production lines, workers mainly rely on sampling and checking the raw material proportions by manually running the batching discs, followed by control. This method is not only slow and untimely but also inaccurate. Introducing computer control improves control speed and proportion accuracy, reduces worker workload, and stabilizes the chemical composition of the sinter. In the sintering batching production line, a frequency converter controls the rotation speed of the discs, thereby regulating the feeding speed. Raw materials fall through valves onto a weighing belt, then onto the main belt. The raw materials from each bin are mixed proportionally on the main belt before being sent to the mixing system. The disc feeding quantity is measured by a weighing sensor, with a signal of 4-20mA, directly sent to the Quantum analog input module. The controller calculates the instantaneous and cumulative feeding quantities. The given feeding quantity and the actual material flow rate are calculated by the PLC's PID controller, and the PLC outputs a 4-20mA signal to the frequency converter, forming a closed-loop control that ensures precise feeding. The process flow is shown in Figure 1. Figure shows the process flow diagram of the batching system: 2. Batching System Control Principle Diagram: II. Batching System Program Flowchart Batching System Electrical Part Batching System Instrumentation Part III. Batching System Control Method and Control Model In this batching system, there are two control methods for automatic batching: local control and remote control. Local control involves the operator directly inputting the batching setpoints from the upper level based on production requirements and experience. Remote control involves calculating the setpoints for various batching materials using a model, and then calculating the batching setpoints for each silo based on the proportion of each material. The most complex, important, and demanding part of the batching system is model calculation. This system mainly uses a first-level model: mainly including the sintering mixture quantity control model, fuel ratio control model, and return ore ratio control model, etc.: l The sintering machine mixture quantity control model is a first-level process model designed to maintain a constant material level in the online control sintering machine mixture silo. The fuel ratio control model controls the fuel ratio in the mixture online. The model fully considers the carbon and moisture content to maintain a constant carbon content in the sinter, thus controlling solid fuel consumption during sintering production. The return ore ratio control model aims to keep the return ore ratio in the sinter mixture as constant as possible. IV. Application of Electronic Belt Scales in the Batching System The batching system uses Nanjing Chuangfeng's CF2001 electronic belt scale. The 4-20mA signal from its weighing sensor is directly input to the QUANTUM analog input module. Therefore, the program includes zeroing, physical verification, zero-point identification, and slope correction procedures. Correspondingly, the host computer displays a calibration screen for each scale. During calibration, the screen and the actual operation are coordinated. During normal production, program modifications, system upgrades, and unexpected situations sometimes require the PLC to stop and the program to be reinstalled. This can lead to the loss of some setpoints and calculated values ​​on the calibration screen, causing the belt scale to malfunction. At this point, metrology technicians had to manually recalibrate the scales. The batching system had 28 belt scales, and the calibration procedure was cumbersome. If recalibration was required every time the PLC was powered off, it would inevitably increase downtime and affect normal production. In actual production, the latest calibration screen for each scale could be copied and saved. When a shutdown was unavoidable, recalibration was unnecessary; the zeroing value could be entered directly at the "Manual Zeroing" location on the screen, referring to the previously saved file, and the slope of each scale could be entered in the slope input box. This only took a few minutes. Therefore, when programming, all possible scenarios should be fully considered, and the program's functionality should be fully improved. V. Batching System Software Configuration and Network Construction 1. Software Configuration: The Quantum PLC system uses Concept 2.5 programming software, employing a function block programming method. Concept software has a 32-bit simulator for online simulation. The server and supervisory control (SCADA) software use Schneider Electric Monitor Pro 7.2. MP7.2 uses the ModBus TCP/IP communication protocol to connect the various PLC systems, collecting data from field devices and displaying it on the SCADA system, or writing data from the SCADA system to the PLC. It features reliability, standardization, integration, practicality, and high efficiency. 2. Network Construction and Communication: The system consists of a three-layer network: Ethernet, MB+ network, and remote I/O network. Ethernet: The PLC host is connected to a switch via a 140 NOE 771 10 module. The switch is connected to other switches via single-mode fiber to form a fiber optic ring network. The SCADA system is also connected to the switch via Ethernet. l MB+ Network: Due to the wide distribution and long distances of the PLCs throughout the sintering system, they need to be connected via an MB+ network. Modbus Plus can be configured with 64 nodes, and node configuration can be achieved through the PeerCop function in the Concept software. Each configured PeerCop specifies a register, which is a 16-bit digital value. This data transmission method is particularly suitable for transmitting status information between PLCs and for communication between distributed nodes on the Modbus Plus network. l RIO Network: The RIO network is a high-speed (1.544Mb/s) local area network using coaxial cable as the transmission medium. Media redundancy is employed in this system. When a communication failure occurs on one channel, the system automatically switches to another channel, ensuring normal data acquisition and control between the PLC and remote I/O. VI. Summary The batching instrumentation system program involves not only primary model calculations but also various control mode changes and dynamic changes in materials at each silo. Therefore, the program's development and debugging are highly complex. During maintenance, a thorough understanding and assimilation of the program's control principles are essential to flexibly and promptly resolve problems and minimize downtime when encountering faults or requiring system modifications. In conclusion, since its commissioning, the system has operated smoothly, reducing operational failure rates and worker workload while improving labor productivity.