Automation Insider: Flexible, Scalable Fieldbus For Asset Performance

By Gary Mintchell, Editorial Director

Welcome to the fourth column in this series covering industrial networking and how these networks benefit maintenance, reliability and operations functions in a plant. I have previously covered HART Communication Protocol, Foundation Fieldbus and the FDT standard for displaying status and diagnostic information from the field. This month’s topic is “all things Profi.”

Profibus is a device-level fieldbus for connecting various devices, primarily in factory automation. Profibus PA extends the standard into process automation applications. Profinet is the Ethernet implementation of the standard. Similar to HART and Foundation Fieldbus, Profi networks are digital networks featuring simplified wiring among devices and controllers.

Via a single cable, Profibus links controllers or control systems with decentralized field devices (sensors and actuators) on the field level and also enables consistent data exchange with higher-ranking communication systems. The consistency of Profibus is enabled through a single, standardized, application-independent communication protocol that supports fieldbus solutions in factory and process automation, as well as in motion-control and safety-related tasks.

Part of the Profibus value proposition is its ability to cut costs and improve operations across the life cycle of a plant—from design though ongoing maintenance and even revamps. It does this in many ways: At the engineering stage, it simplifies plant design, eliminates hard wiring and requires less hardware, leading to faster commissioning and lowered costs. It supports better diagnostics, so commissioning is much faster. Profibus also helps achieve improved productivity and higher product quality through the delivery of better, more-timely data to operations and management staff. In addition, it supports advanced strategies that allow plants and equipment to be better managed and maintained.

A huge number of vendor companies have developed Profibus-capable devices for discrete and process automation, so system integrators have plenty of choices. This leads not only to security and flexibility of supply, it also means healthy competition among vendors—and pricing that is highly favorable to end-users. The applications coverage has been continuously extended to include new and relevant functionality, such as integrated Functional Safety and advanced Motion Control. Users have made substantial investments in training, tools, inventories and plants.

Benefits of using a digital fieldbus include:

• Plant asset management. Information from process instruments, sensors and actuators are available in the controller.
• Engineering and documentation. Engineering is simpler, and the documentation is far less complicated as hundreds of separate wires are reduced to just a single cable.
• Installation. With less hardware, installation is easier and faster.
• Commissioning. Devices can sequentially be brought online, one by one, with startup initiated from a central location.
• Process variables. The diagnostic information and status bytes available tell the user if they can trust the process variable or not.
• Manufacturing flexibility. As demand shifts, manufacturing changes can be implemented rapidly.
• Maintenance and operations. With the powerful diagnostics of a fieldbus come improved availability and reduced downtime.

I’m still stung by the question posed to me during a presentation at the last MARTS Conference: “Do these things really work?” The answer is yes. I’ve talked with many engineers who have implemented these networks, plant and division managers who have seen the benefits and maintenance professionals who have saved countless hours figuring out a problem. Are you moving into the digital era? Let me know your results and frustrations, if any. MT

Gary Mintchell, gmintchell@atpnetwork.com, is Executive Director and Editorial Director of Applied Technology Publications. He also writes at www.themanufacturingconnection.com.