Protocol Series: What is Profibus?

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What is a protocol?

We’re talking about a communications protocol, which is a common ‘language’ which allows connected devices to ‘talk’ to and understand each other. An industrial control system will generally use a common protocol or language between devices such as a PLC, a HMI touch screen, a variable speed drive or a SCADA system.

What is Profibus protocol?

Profibus is a relatively common open communications protocol which uses a serial interface such as RS-485. It was developed by the German government in collaboration with automation manufacturers in the late 1980’s, and is currently maintained by an organisation called PROFIBUS and PROFINET International (PI).
There are two variants of Profibus in use today: Profibus DP (Decentralised Peripherals – used for connections between sensors, actuators and control systems), and Profibus PA (Process Automation – a less common variant used to provide power to instruments as well as carry information).

Which devices support Profibus?

Siemens is the primary Profibus manufacturer offering wide support for Profibus DP and PA across its entire range. Most of the other manufacturers offer Profibus on at least some models, usually via addon communication cards. Gateways and converters to translate into Profibus from other protocols are readily available.

(photo source: Siemens)