Safety Basics – Conventional vs Combined Safety

Safety PLCs are special controllers built and certified to meet international safety requirements such as NFPA 79,  IEC 62061, IEC 13849-1 or IEC 61508. All of these safety standards define levels of risk reduction. Conventional Safety PLC Principle The original safety PLC concept required that normal PLCs and standard I/O could not be mixed with safety PLCs and safety components in the same network. […]

Industrial Safety: PROFIsafe Profile Overview

PROFIsafe (PROFINET safety) is a safety communication technology for discrete manufacturing and process automation systems. It was developed by PROFIBUS / PROFINET International (PI) to meet Functional Safety requirements for PI communication technologies (PROFINET, PROFIBUS, and PROFIBUS PA).  As we talked about in Safety Basics, the PROFIsafe role in the safety universe is to minimize the chance of incorrect functioning of the control system. Incorrect functioning for a PROFsafe […]

PROFIsafe Profile: Industrial Safety

PROFIsafe profile details are incorporated into the PROFIsafe driver firmware in both an F-Controller and an F-device. The PROFIsafe driver is an encoding/decoding package that ensures the integrity of the safety portion of the communication. Network Communication Challenges The following errors are potential problems in network communications. Repetition – malfunction of a bus device causes old and obsolete safety messages to be repeated at the wrong time […]

Hazardous Environments and Industrial Automation

Hazardous environments are areas where flammable liquids, gases or vapors or combustible dust exist in sufficient quantities to produce an explosion or fire. In hazardous environments, specially designed equipment and special installation techniques must be used to protect against the explosive and flammable potential of these substances. (OSHA Publication 3073) There are three factors which have to be present in order for there to […]

Process Automation Background

 History The “Process Industry” includes the waste water treatment, food & beverage, chemical, oil & gas, and pulp & paper industries. In the past, plant operators had to physically monitor performance values and the quality of outputs to determine the best settings on which to run production equipment. Process automation simplified this with the help of sensors at thousands of spots around […]

Process Automation Basics

PROFIBUS PA ( Process Automation) was designed to work along with PROFIBUS DP (Decentralized Periphery) to make a consolidated network using DP for high-speed communications and PA for process environment. A network consists of a DP master (controller), a DP segment, a DP/PA coupler and the process network with slave devices. Fast DP controllers connected to slow PA instruments. How does […]


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 […]

Configuration in Run (CiR) for PROFINET

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. […]

The Future of Process Automation and PROFINET

The Industrial Internet of Things (IIoT) is making direct access to process data at all levels more necessary by the day. End users, DCS and PLC manufacturers require process device data for control, monitoring, problem reporting, and inventory management simultaneously. There is a limit to the amount of data traditional fieldbuses like PROFIBUS PA can handle due to data packet […]

PA Profile for PROFINET

PA networks are designed to be operated as process  “islands” within a larger PROFIBUS DP controlled network. The total network could consist of several of these “islands” all controlled by a single PLC/DCS. Each PA “island” starts with the DP/PA coupler which acts as the PA master and consists of several PA devices on a segment. Each “island” could be […]

System Redundancy with PROFINET

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 […]

Redundancy Terms: S1, S2, R1, R2

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 […]