Fieldbus systems are communication networks used in industrial automation to connect various devices, such as sensors, actuators, and controllers. They enable real-time data exchange and control between these devices, allowing for efficient monitoring and management of processes. By using a standardized protocol, fieldbus systems reduce wiring complexity and improve system reliability. These systems can support multiple devices on a single network, making them cost-effective and scalable. Common types of fieldbus systems include Profibus, Modbus, and CAN bus. Each type has its own specifications and applications, catering to different industrial needs and environments.