Choosing industrial communication interface for an automation device requires that the network functionality and presuppose task be ascertain for ease of selection.
Selecting a Profinet interface may enhance industrial communication for devices. In this article, we will consider some of the enhanced features of Profinet interface as relate to network performance.
How Profinet Enhances Real Time Communication
Profinet has a unique feature that enable standard and real-time communication to coexist in parallel. The IEEE 802.3 Standard is designed to ensure a problem free communication between Profinet devices and among Profinet devices and other standard Ethernet devices. Communication using Profinet is scaled on three performance levels which includes:
- Transmission of engineering data and non-time critical data: available for all automation devices.
- Real time (RT) channel: mostly use for process data transmission.
- Isochronous real-time (IRT): mostly available for motion control
Profinet Versus Time Sensitive Network (TSN)
TSN is a combination of the wide range of IT networks with the robustness and determinism of automation networks. It is not a replacement to Profinet as has been perceived rather it is a part of ethernet and since ethernet is not an end-to-end protocol, application layer protocols like Profinet is needed to complete data delivery.
TSN offers a layer 2 in the ISO/OSI model which corresponds to RT and IRT Profinet technologies. Because TSN is an open standard that is supported by many semi-conductor vendors, it does not negate any of the properties of Profinet such as diagnosis, configuration and alarms etc. neither will Profinet become outdated in the near future.
Conformities in Profinet
Conformities are the requirements in automation devices before deploying a Profinet Protocol. Manufacturers of automation devices must consider classes of conformities before an implementation step for a profinet device interface is selected because the interface type affects achievable conformance class. Key functions of the three conformance classes and their advantages are as follows:
Conformance Class – A: in this class, existing Ethernet network are integrated with some basic functions of Profinet. All applicable IT services can be used without restriction. This is majorly applied in building automation and process automation.
Conformance Class – B: this class includes all functions applicable to CC-A with an additional support to user friendly device replacement without using any technical tools. All applicable IT services can be used without restriction. This is majorly applied in higher level machine control and deterministic automation system.
Conformance Class – C: this class also includes all the function of CC-B with an addition support to high precision, deterministic data transmission and Isochronous applications. All applicable IT services can be used without restriction. This is majorly used in motion control.
So far, we have considered some of the enhanced features of a Profinet Protocol and how device manufacturers can capitalize on them in their product design. It is importance that before deploying any automation solution to client facilities that system integrators as well as engineers should be better informed on the network functionality and presuppose task for ease of selection of the relevant Profinet Protocol.
Written by Emmanuel Okih
Automation and Control Systems Engineer and Freelance Writer
Edited by Shawn Tierney
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