PROFINET Position Measurement and Motion

  • February 01, 2011
  • TR Electronic
  • Feature
February 2011By Chris BowmanIn today's competitive manufacturing industries, companies are striving for long term growth by continuously increasing productivity and focusing on production costs. Companies need to become lean and upgrade their equipment to operate as effectively and efficiently as possible. To fulfill these demands, automation technologies must be applied extensively. Ethernet communication, specifically the PROFINET adaptation, presents automation experts with another avenue for improving system design, achieving growth and increasing competitiveness.PROFINET falls under the umbrella of Ethernet communications. In the world of Information Technology, Ethernet has been around for almost 40 years and the concept of Ethernet has evolved and grown into what we now take for granted as common technology in our daily lives. However, in recent years we have seen the migration of Ethernet communications into Process Control and Motion Control Applications. This new technology allows for faster communication, tighter control loops and more advanced diagnostics, which ultimately leads to enhanced productivity. Although there are still lines in the sand, between the worlds of IT and Industrial Automation, those lines are starting to blur as the two domains have started to share their experiences and expertise. It is paramount that companies foster the cooperation between these two organizations, as there is much to be learned and many financial gains which can result.PROFINET IO was developed for Real Time (RT) and Isochronous Real Time (IRT) applications. It has been designed to facilitate the data exchange between Ethernet field devices, such as Encoders, Transducers and Laser Sensors, as well as Industrial Controllers, Drives and SCADA systems. In the following example you can see that position and velocity information is produced by a rotary encoder. That information is then made available on the network to be consumed by the PROFINET controller or other devices which require that information. Only devices that require the information consume it, others ignore it and process packets relevant only to them. By using General Station Description (GSD) files, features of a device are specified. This allows for the building of communication packets for parameter transfer, cyclical data exchange and alarm updates.Industrial sensors, especially more sophisticated devices like rotary encoders, linear transducers, and laser distance devices are traditionally wired using a point-to-point connection or Fieldbus interface, Ethernet offers new possibilities to transport data at an appropriate speed for closed loop control. Additional protocol changes to standard Ethernet allow for the realization of a deterministic behavior in respect to data transport time, and also the synchronization between devices. PROFINET combines the experience of PROFIBUS and Industrial Ethernet into one technology. Based on the standard Ethernet ISO/OSI model, PROFINET allows for Isochronous Real Time (IRT) data exchange by: making use of the standard Ethernet ISO/OSI communications model when appropriate; skipping the TCP/IP layers when they are not required; and reserving bandwidth and scheduling of network traffic to ensure motion control is given priority. So what could this all mean to your business? On a recent project, TR Electronic worked with an OEM to upgrade their machine design to PROFINET. This machine builder needed to provide their customer with a machine that was able to synchronize multiple print heads along with “on the fly” cutting shears. The decision to use PROFINET was made because of the number of axis requiring synchronization and the built in diagnostic features. Through the use of TR’s compact drive and encoder products, PROFINET provided the right communication technology to improve the printing process. The resulting design improved product quality, reduced waste and increased product throughput. This upgrade would not have been possible without the power of PROFINET.The requirement for more bandwidth, faster processing speeds and smaller devices will continue to push the envelope of Ethernet based technologies. When making the decision to move forward with your PROFINET installation you should follow the “Three Es”, Educate, Evaluate and Experience. Educate yourself on the standard by participating in training seminars or online webinars; Evaluate your options by comparing the available products and technologies; Experience the advantages by working with manufacturers on product demos and upgrade options. By understanding Ethernet and choosing the right products, you too can enjoy the benefits of a successful PROFINET installation. Author BioChris Bowman is the Technical Product and Service Manager for TR ELECTRONIC North America. With over 15 years in Automation, Chris has extensive knowledge of automation systems and real world experience in Manufacturing, Maintenance, Engineering and Technical Education. Learn More

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