2021.02.22
Summary:The hopper scale is a device suitable for hopper weighing feeding and discharging control during unloader operation; dynamic load tilt control of the hopper; vibrating feeder vibration point setting control; stock stop vibration point control; material level loading warning and alarm point setting control.
With the fierce competition in the domestic steel industry market and the increasingly busy business, the traditional information processing and measurement methods with large errors have been difficult to meet the actual business needs. In order to further improve the management level and competitiveness, and make full use of the development results of computer technology and information science and technology, the company improves the weighing control system of the blast furnace hopper scale, and completes the formation of a modernized measurement system based on the computer system. Through the implementation of the project, a steel company's coke consumption management to provide automated means of timely, accurate, systematic and complete data and information to reflect to the customer, thereby reducing operating costs and maximize corporate profits.
1 hopper scale weighing system design background and intention
An iron and steel company currently has three blast furnaces, a total of eight hopper scales: 1 # blast furnace two hopper scales, 2 # blast furnace two hopper scales, 3 # blast furnace four hopper scales. Blast furnace feeding using computer-controlled hopper scales for feeding, measurement, but after analysis found that the control system exists in the measurement and actual consumption deviation is too large, so in order to effectively monitor the input of materials, improve the accuracy of measurement, now improve the system design to achieve the hopper scales metering system, to achieve real-time monitoring and measurement of coke consumption of the three blast furnaces, to ensure that the data information is accurate and reliable.
2 Deficiencies of the current system
At present, the hopper scale will be 4 ~ 20mA signal and the hopper switch door digital signal are connected to the L1 PLC dosage control system, the system process is the trolley arrives at the hopper scale, open the hopper door to start loading, the end of the loading off the door. When the control system receives the trolley arrival signal, the data from the hopper scale is recorded as tare weight, and when the signal from the hopper door closure is received, the data from the hopper scale is recorded as gross weight, and then the system calculates and saves, displays and uploads the net weight. However, there is a certain mechanical time difference between the hopper closing signal and the complete closing of the door, and the time is not fixed, during this period of time, there is still coke loaded into the trolley, but it is not recorded in the gross weight, so each time the collected and calculated weight and the actual consumption of the weight have a large error, resulting in a large difference between the monthly cumulative amount and the actual consumption of the cumulative amount.
3 Improve the design and realization of automatic batching system
3.1 Improvement of system structure
Improve the metering and batching system by connecting the 4~20mA signal of hopper scale to the dual signal transmitter, split into 2 ways, one way to access the L1 control system, and one way to access the new weighing collection system. The original PLC control system's acquisition and transmission methods remain unchanged, while the new weighing acquisition system communicates directly with the weighing equipment by installing RTU devices at the site of each district and city, reads the data by using the Modbus/Tcp protocol, and then obtains the amount of coke loaded each time by judging the stabilization algorithm.
The RTU devices added in each district city are connected to the backbone Ethernet through the network interface, and the system communicates with the regional RTUs through the Ethernet, using the Modbus protocol format to interact with the data at each site.The Modbus protocol defines the information structure that the controllers can recognize and use, and when communicating on a Modbus network, the protocol enables each controller to know its own device address, to And identify the data addressed to it, take out the data information contained in the packet, the controller can also organize the answer information, and use the Modbus protocol to transmit this information.
3.2 System Design and Algorithm Implementation
Add 1 STC-511RTU to each area, which uses the open Modbus/Tcp communication protocol. In order to improve data communication and processing efficiency, the software adopts object-oriented multi-threading technology to develop Modbus/Tcp-based C/S architecture software, using the relevant digital and analog data acquired to carry out the corresponding logical judgment, data analysis, and save the resultant data to the SOLServer database. In order to facilitate users to query and analyze the measurement data, the system is also designed with B/S architecture, and various accumulated data, analysis data and report data are published on the Web, so that the corresponding functional operations can be easily realized through the browser.
