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 (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 […]
PROFIBUS PA is a slowly-transitioning, low-volume data network for Process Automation, based on Manchester-encoded Bus-Powered for Intrinsic Safety (MBP-IS). The rate of data change is within the range of tens-of-milliseconds to multiple seconds. A PROFIBUS PA network operates over a single cable that provides power and communication. In contrast, PROFINET is a high-speed, high-volume data network for Industrial Automation, based on […]
In general, the process automation industry has many complex requirements. Due to complex automation processes and high restart costs, some process networks require continuous production; device introduction, replacement or re-parameterization without interruptions. The original PROFIBUS Configuration in Run (CiR) specification addressed this requirement. In fact, CiR provides the ability to reconfigure, insert, remove, or replace devices or modules without stopping the control application. […]
Automation systems have always been designed to meet two key criteria: reliability and availability. Reliability is the first priority- data that enters the network should pass through it unchanged and should always make it to its destination. But availability is a more complex problem because it’s not just about moving bits across a network once they’re transmitted. Instead, availability means […]
System redundancy for PROFINET comes with some strange terminology: S1, S2, R1, and R2 all show up in technical and marketing literature. They’re usually presented without much context, so we’ll clarify them here. System redundancy relies on the concept of multiple connections to a device or controller to maintain the system in the event of a failure. In our article […]
The Media Redundancy Protocol (MRP) is something we’ve covered before, but we haven’t touched on the Automanager yet. It’s an entity that was introduced in the 2016 version of the MRP specification (IEC 62439-2-2016), and it helps make a MRP ring even more fault-tolerant. Making Media Redundancy… More Redundant MRP originally had two entities: a Client and a Manager. Clients […]
PROFINET implements redundancy in multiple ways to tolerate multiple types of failures. A PROFINET system can be designed to tolerate a failure of a device, a controller, or even the media that connects them within a network. But there’s another component of a PROFINET system that can fail: the network itself. Availability in the worst-case scenario Network redundancy is a […]
The concept of redundancy in PROFINET is broken into several parts: device, network, media, and controller redundancy. This article takes a look at controller redundancy and why it’s more complex than device redundancy. There are two moving parts that make Controller redundancy work: coordination between controllers (usually some vendor-specific communication between PLC applications) and how devices handle simultaneous connections (a […]
It’s three A.M. Third shift is in full swing when a distributed I/O rack decides to stop working. But instead of stopping the line, the system seamlessly switches over to the redundant I/O rack and just logs a “maintenance requested” message with the operator. The maintenance crew doesn’t have to scramble, and the night continues without a hitch. That’s device […]
Editor’s note: This article is an excerpt from the PROFINET Developer Workshop offered by the PROFI Interface Center. For more information on this or other advanced topics, contact them at [email protected]. Alarms, Diagnostics, Errors… these terms get thrown around a lot when people discuss how to communicate when bad things happen on the network. But what do they really mean? […]
