What technology is used to link multiple programmable logic controllers together?

The technology that is used to link multiple programmable logic controllers (PLCs) together is Fieldbus. Fieldbus is a digital, serial, and multi-drop communication protocol that allows various devices, including PLCs, field devices, and sensors, to communicate over a common network. This technology is specifically designed for industrial automation and control systems, enabling different components to work together seamlessly in real-time applications.

Fieldbus supports complex communications and decentralized control, allowing for more efficient data exchange compared to point-to-point wiring systems. This is essential in systems where multiple devices need to exchange information, making it a preferred method for integrating multiple PLCs within the same network. The approach improves robustness, reduces installation costs, and simplifies system configurations.

While other options like Modbus and Controller Area Network (CAN) are also used for device communication, they serve different use cases or have different architectural approaches. Modbus is a widely used protocol for serial communication, primarily in industrial environments but is not specifically designed to create a multi-device network like Fieldbus. Similarly, Controller Area Network (CAN) is typically used in automotive applications and for connecting microcontrollers, rather than focusing on the networking of PLCs in industrial automation. The Human-Machine Interface (HMI) serves as a