Automation and Control System for Crushing Plants and Concrete Batching Plants

We call the complete set of computer hardware and software that lets you run a crushing plant or concrete batching plant from a single point, either from the control cabin or remotely, an automation and control system. It keeps many machines on the line working in sync and carries out commands for different functions at the same time.

How Does the System Work?

Plants can be operated in fully automatic mode, manually or automatically from the cabin, or by remote control. In each case you can start and stop equipment, set capacity and manage material flow. When maintenance is needed or a fault occurs, repair time is shortened and the risk of damage to the machine is kept to a minimum.

System Components

• PLC: the logic of the line runs on a programmable logic controller, where the start-up order of the machines, the interlocks and the shutdown scenarios are defined.
• SCADA and operator panel: a touch screen in the cabin shows the line diagram live, with the status, current draw and alarms of every machine visible on one display.
• Field instrumentation: level sensors, belt drift and speed switches, temperature and vibration sensors, and load cells.
• Motor control centre: starters, variable frequency drives (VFD) and protection relays automatically match feeder speed to crusher load.

Sequential Start-Up and Interlocks

On crushing lines, machines are brought on in the opposite direction to material flow, from the stockpile back towards the feeder. If one machine stops, every stage before it stops on its own, so no belt ever starts under load and conveyor blockages are avoided. As the crusher current nears its limit the feeder slows down, and once the current is back to normal the feed rate goes up again.

Remote Monitoring and Reporting

When the automation panel is networked, shift reports, tonnage produced, downtime and alarm history are all logged. If something goes wrong, the service team can check the alarm records over the connection and reach a first diagnosis without visiting the site, which cuts repair time.

Safety

Emergency stop buttons, pull-cord switches and guard sensors are connected straight to the safety circuit. Whenever this circuit opens, the equipment concerned stops regardless of any command from the automation. The lock-out/tag-out (LOTO) procedure used during maintenance is also supported through this circuit.