Views: 0 Author: Site Editor Publish Time: 2026-07-23 Origin: Site
Two discharge cars at a steel plant's sintering yard were built years ago with only local manual operation available. Operators had to control the cars on-site, facing poor working conditions, heavy labor, and safety risks. Positioning errors caused frequent material spillage. There was no automatic interlock between the cars and bin level signals or the main belt, creating overflow hazards. No video surveillance meant the control room could not monitor operations remotely.
To address these issues, the plant decided to upgrade the control systems for both discharge cars to enable remote manual and remote automatic operation. Wuhan Forward Technology undertook the design, supply, installation, and commissioning of the control systems.
1. Gray Code Bus High-Precision Positioning
Gray code bus was installed along the car travel tracks. Car-mounted antenna boxes read position signals in real time, achieving ±2mm accuracy and ensuring precise stopping at designated discharge points—eliminating spillage.
2. Dual PLC Control System
Both the car and ground sides were equipped with S7-1200 PLCs for real-time data exchange. The ground PLC reads bin level signals and triggers alarms or interlocks with the main belt when bins are overfilled. The cars also interlock with the belt pull-cord—when the pull-cord trips, the cars stop immediately.
3. Remote Intelligent Control Platform
Two industrial PCs were installed in the control room, running HMI software that displays real-time equipment status. Operators can control forward, reverse, and dumping operations entirely from the control room. The system alerts for position signal faults and bin full conditions, working alongside video surveillance for precise control.
4. Variable Frequency Drive
The car travel motors use variable frequency drives with braking. Smooth acceleration and deceleration improve positioning accuracy and reduce mechanical wear.
5. Independent Video Surveillance System
Multiple cameras were installed along the car tracks, feeding images to the control room display wall. The video system operates independently from the control system, allowing operators to monitor car positioning and material discharge status in real time.
6. Multi-Level Safety Protection
Position signal faults trigger automatic alarms; full bins and belt pull-cord events trigger automatic shutdowns; emergency stop devices are installed on both sides of each car; communication loss, data errors, overflow, and positioning faults all trigger alarms and emergency stops.
7. High-Reliability Wireless Communication
Industrial-grade wireless bridges ensure stable transmission of control signals and data between the car and ground.
After commissioning:
Positioning accuracy reached ±2mm, completely eliminating spillage.
Remote operation fully replaced on-site manual control, significantly reducing labor intensity.
Process and safety interlocks are fully operational—overflow and pull-cord events trigger automatic shutdown.
Full video coverage gives the control room real-time visibility of operations.
The system passed 360 hours of continuous operation before formal handover and continues to run stably.
