PLC automation: what is it and what is its role?

PLC and automation are two concepts that go hand in hand. PLCs (programmable logic controllers) have become essential for the industrial and technological development of any company. More and more businesses are turning to logistics automation to boost their warehouse throughput. In a market constantly in flux — with same-day deliveries and changing consumer habits — automation delivers speed and reliability in moving large volumes of goods.

What is a PLC?

A PLC is an industrial computer that serves a basic function: to manage the movements of the automated handling equipment operating in a facility, e.g., stacker cranes and conveyors. To do this, the PLC activates and deactivates electrical devices on each machine, such as signal beacons, relays and motors. One characteristic of PLCs is that they operate in real time. That is, they can react and activate the movements of the machinery in a matter of milliseconds.

The PLC (programmable logic controller) is the key piece of the automation of logistics processes. Nowadays, many automated warehouses have a PLC processor to facilitate the automation of movements and optimise the logistics process. It provides a centralised and programmable control platform that can perform multiple tasks.

How a PLC Works in a Logistics Facility

A PLC typically uses a fieldbus, i.e., an industrial communication network that connects the system with the various components in an automated warehouse. These include sensors, electric motors, valves and switches, among others. PLCs are made up of several components: one is the central processing unit (CPU), which processes the PLC program and stores all related data. PLCs also have modules to enable the physical connection between the industrial computer and the automated systems to be moved.

Through the information received by the sensors and input devices connected to each machine, the PLC processes the data and sends orders to the handling equipment. By digitising and automating all product movements, the PLC can also monitor and record real-time data, such as operating temperature or machine performance. A PLC usually works in conjunction with a supervisory control and data acquisition (SCADA) system. This tool facilitates decision-making in the warehouse: it allows users to know the status of a machine or the current location and eventual destination of a moving pallet.

Core Functions and Applications

The PLC is used to control, automate and classify processes in warehouses and distribution centres. Logistics centres are complex and require careful planning and coordination of movements to ensure that products move correctly. Key applications include:

• Distribution and classification of packages: The PLC is in charge of programming and controlling the conveyors that transport the packages to guide them to the correct routes.
• Inventory management: In a warehouse the PLC can program and control the movements of products and packages to keep a precise record of inventory levels.
• Safety management: PLCs can be outfitted with safety devices to ensure reliable machine operation and minimise any possibility of error, reducing downtime and repair costs.

Advantages of Using PLC in Logistics

The use of programmable logic controllers offers numerous benefits for modern supply chains:

• Process automation: the PLC allows the automation of processes that would otherwise have to be carried out manually, which saves time and reduces errors.
• Flexibility: the PLC is programmable making it adaptable to different logistics needs and requirements, since it can be configured to perform a variety of tasks.
• Improves efficiency: the PLC is capable of performing tasks with very high precision and speed, which helps to optimise the activity of the process.
• Cost reduction: by automating processes, the need for labour is minimised and errors are reduced, which in turn is a cost reduction.
• Real-time monitoring: the PLC is able to monitor processes in real time, which helps improve performance and make real-time adjustments.
• Improves safety: the PLC can be programmed to control and automate the movements of equipment and machines safely, which reduces the risks of work accidents.

Integration with Warehouse Management Systems

The Warehouse Management System (WMS) is an essential tool in the industrial supply chain. Easy WMS controls and optimises all warehouse operations, maximising performance and cost-effectiveness. It provides significant improvements such as 99% error elimination and 60% productivity improvement. Additionally, the Warehouse Execution System (Easy WES) orchestrates tasks and resources to boost productivity, while the Warehouse Control System (Easy WCS) integrates automatic equipment for synchronised material flow control.