Fieldbus
A family of digital communication protocols used to connect field devices with controllers in industrial automation installations.
What is Fieldbus?
Fieldbus is a general term for a family of digital communication protocols used in industrial automation to connect field devices (sensors, actuators, drives) with PLCs and DCS systems. Fieldbus replaced traditional 4-20 mA analogue connections with single digital buses, enabling transmission of multiple signals over one cable.
The most popular Fieldbus standards include PROFIBUS (dominant in Europe), Foundation Fieldbus (used in process industries), DeviceNet, ControlNet and AS-Interface. Each has its own characteristics regarding speed, topology, maximum device count and target applications.
Modern automation is increasingly migrating from traditional Fieldbus to industrial Ethernet solutions (PROFINET, EtherNet/IP, Modbus TCP), which offer greater throughput and easier IT integration. However, many industrial installations still use legacy Fieldbus networks, requiring protocol gateways for integration with modern systems.
Why does it matter?
Fieldbus networks are the lifeblood of industrial installations - any communication disruption can lead to production stoppages or hazardous process states. Legacy Fieldbus protocols provide no encryption or authentication, meaning an attacker with physical access can manipulate process data. OT network inventory and security assessments should cover all Fieldbus segments.
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