Abstract : This paper introduces the application of QUANTUM PLC in converter auxiliary equipment and secondary dust removal systems. The hardware configuration, software design, and implementation functions of the control system are described in detail. 1. Overview The mechanical equipment of the auxiliary equipment system of a 120t converter in a steel plant includes the front and rear fire doors, the converter main control room roller shutter door, the mobile flue trolley, the oxygen lance traverse, locking devices, and the motors and solenoid valves of the lifting hood device. The converter secondary flue gas dust removal system mainly consists of a converter gate-shaped exhaust hood, flue gas regulating valve, charging system exhaust hood, air volume switching valve, dust collector unit (bag filter), dust conveying device (ash discharge valve, scraper conveyor, ash storage bin), main fan unit (main fan, motor, hydraulic coupling), compensator, flue gas pipeline, chimney, and maintenance and repair equipment. 2. System Configuration In the entire 120t converter L1-level basic automation control system, the NO.16 converter auxiliary equipment and secondary dust removal PLC mainly completes the electrical control of the process equipment of the 120t converter auxiliary equipment and secondary dust removal system. Centralized monitoring and operation of the equipment are performed through the CRT screen on the HMI. Two dedicated HMI devices are used as backups for other HMIs in the main control room, sharing operation. One is the HMI for the tilting, oxygen lance, and auxiliary equipment systems, and the other is the HMI for the blower and secondary dust removal system. The electrical control of the auxiliary equipment and secondary dust removal process equipment is integrated into the I/O station of the NO.16 PLC, i.e., the NO.16 PLC cabinet. Interlocking signals from other systems related to this system can be interconnected through a communication network. The system configuration diagram is shown in Figure 1. [align=center] Figure 1 System Configuration Diagram[/align] 3. Software Design The supervisory control and data acquisition (SCADA) software uses Monitor Pro, which runs on a regular PC, operating on Windows 2000 or XP. It boasts powerful network capabilities and a Client/Server architecture. It comprises two main parts: the HMI (Host Interface) component – ​​The Client Builder, and the Real-Time Database (RTDB) component – ​​The Configuration Explorer. The HMI is shown in Figure 2. [align=center]Figure 2 HMI[/align] Monitor Pro Features: 1. Large-capacity real-time database 2. Powerful network connectivity 3. Secure and reliable network and system architecture 4. Online update functionality; The HMI is shown in the figure. The program control software uses Concept 2.6 programming software, which is based on the Windows integrated development environment. It contains all programming languages ​​specified in IEC-1131; users can create their own reusable function blocks; the built-in simulation debugger allows for offline simulation, accelerating application software development and debugging; it provides up to 7 layers of software access protection to prevent unauthorized access, ensuring security and reliability; it has powerful online help functions, a user-friendly interface, and a large amount of information, greatly facilitating application developers. 4. Functional Implementation 4.1 Main Auxiliary System Control Functions During a smelting cycle, the furnace front fire baffle is open during the addition of molten iron, scrap steel, converter slag removal, and waiting periods. It is closed from the start of oxygen lance descent after converter charging until the end of tapping. When the door is closed, observation of the furnace flame or sampling can be done by opening the observation window and sampling window on the door. The two flame observation windows and the sampling window are controlled independently. The door movement is accompanied by audible and visual alarms. The movement control of the furnace rear fire baffle door is completed on the local control box, requiring the main control room CRT to display the door's open/closed status. The door automatically stops when it encounters a proximity switch. An audible and visual alarm sounds and flashes during door movement. The movement control of the converter main control room roller shutter door can be completed on both the local control box and the main control room CRT. The lifting and lowering are initiated by buttons on the local control box and the main control room CRT, automatically stopping upon contact with the limit switch. When the roller shutter door descends, the protective plate stops descending when it encounters the lower limit switch; when the roller shutter door rises, the protective plate stops rising when it encounters the upper limit switch. The equipment also has a mechanical upper limit for over-limit operation. The movement control of the mobile flue trolley can be completed on the machine-side control box. The movement can be jogged to adjust the stop position. The lateral trolley is used for changing oxygen lances or converter repairs, moving laterally along with the lifting trolley and oxygen lance. The lateral movement and locking operation of the oxygen lance can be completed on both the main control room CRT and the local control box. The oxygen lance traverse carriages are controlled by inching to improve positioning accuracy. During normal production lance changes, both carriages move in the same direction; one moves from the working position to its waiting position, while the other simultaneously reaches the working position. During converter lining repairs, the two carriages move in opposite directions, each reaching its repair position. The oxygen lance traverse carriage track is equipped with six limit switches, three per carriage: one signaling arrival at the working position, one signaling arrival at the waiting position, and one signaling arrival at the repair position. An electro-hydraulic cylinder positioning and locking device is installed at the working position of the traverse carriage. When the carriage stops after encountering the working position limit switch, the positioning and locking device activates after a 0-10 second delay, locking the carriage in the working position. When the working oxygen lance needs replacement or maintenance, after confirming that the oxygen lance has been raised from the oxygen lance inlet on the flue to the oxygen lance lifting and changing position (point H),... First, disengage the locking device of the working position transverse moving car, then start the transverse moving car to the waiting position. At the same time, another transverse moving car (with the oxygen lance already replaced) moves to the working position. When it encounters the working position limit switch, repeat the aforementioned positioning and locking action to complete the position exchange between the working transverse moving car and the standby transverse moving car. The operation control of the fume hood lifting can be completed on the main control room CRT and the local control box. The fume hood has two working positions, upper and lower. The lifting action is started by a system command (manual button), and stopped by a limit switch signal. When the converter is not in the vertical position (0°), the fume hood cannot be lowered. The control location selection switch is located on the local control box. Only one point, the main control room and the local control box, can be in operation at any time. 4.2 Secondary Dust Removal System Control Function The secondary dust removal equipment includes 18 electric butterfly valves. Each dust removal point of each converter high-level auxiliary material silo exhaust hood, middle-level ferroalloy silo exhaust hood, furnace rear ferroalloy silo exhaust hood, and converter furnace rear blowing wire feeding dust removal pipeline is equipped with an electric butterfly valve. Eighteen electric butterfly valves, powered by MCC, with a transmission voltage of AC380V. The secondary dust removal valves have two operating locations: the converter main control room CRT and the local control box. The secondary dust removal electric butterfly valves should be controllable by both the local control box and the main control room. The main control building CRT screen should display valve operation and fault alarms. 1) The electric butterfly valve at each dust removal point in the converter high-level auxiliary material silo is interlocked with the travel switch of the unloading trolley on the silo. When the unloading trolley stops at the top of the silo to be unloaded, the dust removal valve station for that silo opens, while the electric butterfly valves at other high-level auxiliary material silo dust removal points remain closed. After the unloading trolley leaves the top of the silo, the dust removal valve on the top of the silo closes after a 50-second delay. 2) For the secondary dust removal of the intermediate-position ferroalloy silo, the electric butterfly valve at each dust removal point is interlocked with the travel valve of the unloading trolley on the silo. When the unloading trolley stops at the top of the silo to be unloaded, the dust removal valve of this silo opens, while the electric butterfly valves at other intermediate-position ferroalloy silo dust removal points remain closed. After the unloading trolley leaves the top of this silo, the dust removal valve closes after a 50-second delay. 3) For the secondary dust removal of the downstream ferroalloy silo, the electric butterfly valve at each dust removal point is interlocked with the travel valve of the unloading trolley on the silo. When the unloading trolley stops at the top of the silo to be unloaded, the dust removal valve of this silo opens, while the electric butterfly valves at other downstream ferroalloy silo dust removal points remain closed. After the unloading trolley leaves the top of this silo, the dust removal valve closes after a 50-second delay. 4) For the converter downstream blowing wire feeding dust removal pipeline, there is one electric butterfly valve. The valve should be operable both locally and via the main control building CRT. Contact Person: Li Xia Mailing Address: Automation Department, Jinan Iron and Steel Group, No. 21, Gongye North Road, Jinan Telephone: (0531) 88866647 E-mail: [email protected] Li Xia (1979—) is an assistant electrical engineer mainly engaged in the design, installation, and commissioning of electrical automation projects.