In the previous article about HMIs we mentioned what an HMI was. Next, in this article, we are going to show how they are typically used in a PROFINET HMI context. Often, the decision on which protocol to use on the HMI(s) depends on your application requirements and what protocol drivers the HMI supports. So let’s take a look at […]


PROFINET and OPC UA are two common protocols that have some overlap in the automation and process industries, and understanding which protocol to use in a particular part of a network can be confusing. Should a new plant use PROFINET or OPC UA to implement local control loops? What about performance data for an automation cell?  Which protocol is the […]

Network Reference Model

Networks are usually represented by a seven-layer model, the ISO/OSI Reference Model. In the Ethernet world, the seven layers collapse to four. PROFINET uses all four, but not all the time. But we’re getting ahead of ourselves; let’s start at the beginning: the seven layer model. Here’s the seven-layer model with the layers labeled and their functions defined. The layers […]

Time Sensitive Networking – TSN overview

What is TSN? Time Sensitive Networking or “TSN” refers to a set of IEEE 802 standards that make Ethernet deterministic by default. It has evolved from the industry’s use of Audio / Video bridging (A/V) and the need for more devices and synchronized communications. As more users connect up their devices to the Industrial Internet of Things and Industry 4.0 this […]

PROFINET Communication Channels

PROFINET is great at moving information across a network – we never get tired hammering that message home. But exactly how PROFINET moves that information is still a gray area for a lot of users, and deserves a closer look here. To understand how PROFINET moves information, it helps to keep in mind what kind of information it’s moving.  Does […]

Real Time Classes

PROFINET has class, in fact, many classes: Conformance Classes, Real Time classes, media redundancy classes, and even more class(es). This article covers Real Time Classes and how PROFINET works.

PROFINET Conformance Classes

In this article, we will cover conformance classes, as they fit into the mandatory features of PROFINET. Every PROFINET device has a defined set of features which are mandatory based on its conformance class. The conformance classes are divided into three categories, class A, B, and C.

Optional PROFINET Features

We often use an age-old catchphrase during our PROFINET one day training classes, “But wait, there’s more!” when we get to the latter part of the day. We’ve found that most engineers and developers don’t realize what the optional PROFINET features are and their purpose.

What is “PROFINET Shared Device”?

PROFINET offers many features which allow for custom-tailored architectures and automation applications.  An overview of these features can be found in our mandatory and optional features articles.  One of these features is “PROFINET Shared Device”, which gives multiple PROFINET IO controllers (PLCs / PACs) access to the same IO device.  You are probably thinking why would we want to do that? And, how could that […]

What is PROFINET I-Device?

Introduction In a recent article, we covered “PROFINET Shared Device”, which gives a device the capability to share IO data with multiple controllers. This time we will discuss I-Device, which operates on the IO controller level. This optional feature allows a controller to be both a device and controller simultaneously, allowing for controller to controller (some might say peer to peer) communications […]

PROFIdrive Application Class 3

An Application Class 3 (AC3) PROFIdrive device is a “Positioning Mode” drive, and it builds on the concepts of an AC1 device.  However, instead of commanding a drive to move at a desired speed, now the controller asks the drive to move to a desired position.  An AC3 device, as with AC1, handles all of the feedback from the positioning […]

PROFIdrive Application Class 4

PROFIdrive Application Class 4 (AC4) drives are speed-controlled drives.  Like AC1, a controller can command the drive to spin a a given speed.  However, AC4 drives are typically used with high-performance servos rather than the fans or pump motors AC1 is used with.  Because of this high-performance use case, AC4 drives provide a position control loop and cede some of […]