PROFINET (profinet acronym for Process Field Net) is an industry technical standard for data communication over Industrial Ethernet, designed for collecting data from, and controlling, equipment in industrial systems, with a particular strength in delivering data under tight time constraints (on the order of 1ms or less).
The standard is maintained and supported by Profibus & Profinet International, an umbrella organization headquartered in Karlsruhe, Germany.
Interfacing to peripherals is implemented by PROFINET IO. It defines the communication with field connected peripheral devices. Its basis is a cascading real-time concept. PROFINET IO defines the entire data exchange between controllers (devices with “master functionality”) and the devices (devices with “slave functionality”), as well as parameter setting and diagnosis.
PROFINET IO is designed for the fast data exchange between Ethernet-based field devices and follows the provider-consumer model.
Field devices in a subordinate PROFIBUS line can be integrated in the PROFINET IO system seamlessly via an IO-Proxy (representative of a subordinate bus system). A device developer can implement PROFINET IO with any commercially available Ethernet controller.
It is well-suited for the data exchange with bus cycle times of a few ms. The configuration of an IO-System has been kept similar to PROFIBUS. PROFINET IO always contains the real-time concept.
A PROFINET IO system consists of the following devices:
The IO Controller, which controls the automation task
The IO Device, which is a field device, monitored and controlled by an IO Controller. An IO Device may consist of several modules and sub-modules
The IO Supervisor is software typically based on a PC for setting parameters and diagnosing individual IO Devices.
An Application Relation (AR) is established between an IO Controller and an IO Device. These ARs are used to define Communication Relations (CR) with different characteristics for the transfer of parameters, cyclic exchange of data and handling of alarms.
The characteristics of an IO Device are described by the device manufacturer in a General Station Description (GSD) file. The language used for this purpose is the GSDML (GSD Markup Language) - an XML based language. The GSD file provides the supervision software with a basis for planning the configuration of a PROFINET IO system.