Business News
Rockwell Automation Offers Educational Reference Paper on IEEE 1588 Standard
Tuesday 20. January 2009 - White paper details industrial application cases that benefit from time-based control
A new white paper from Rockwell Automation describes how manufacturers can help improve control-system responsiveness and accuracy through time-based control techniques available as a result of the IEEE 1588 standard for industrial networking.
The paper, “An Application of IEEE 1588 to Industrial Automation,” focuses on the IEEE 1588 standard, which defines the Precision Time Protocol that allows for precise time synchronization of automation components using Ethernet. The paper discusses how, by synchronizing the clocks of I/O devices with controllers, the code scan performance of the actual controller can become irrelevant, regardless of the production line speed.
The protocol helps allow automation equipment to achieve synchronization within the 50 nanosecond range when using hardware-driven time synchronization. The paper identifies key use cases that can benefit from time-based control techniques to improve performance results over traditional control methods. Applications addressed in the paper include high-speed inspection, high-speed diverters, precision motion control and machine-wide position registration. By attacking these scan-time hungry applications with a new time-based approach, production rates are no longer limited by a controllers execution time and ability to handle interruptions.
With time-based control, the control technique becomes predictive based on precise knowledge of when events have and will occur, instead of traditional, reactive control approaches which require extraordinary control, network and I/O speeds to match line speed improvements. Time-based control allows line speeds to increase, improving machine throughput. It also enables higher accuracy to diverters, which allows reject systems to perform more precise control over scrap. In addition, a synchronized automation system can help generate precise time stamps for distributed events. These event time stamps, in turn, can improve machine uptime. By using these time stamps in the alarming system, operators can quickly identify the root cause of a machine shutdown.
The IEEE standard is the core technology behind ODVAs CIP Sync technology, which adopts the standard into the industrial networks environment, including EtherNet/IP. CIP Sync provides a set of common data objects on top of the IEEE 1588 standard that industrial components based on the Common Industrial Protocol (CIP) can access. That means manufacturers can apply the standard on an existing CIP infrastructure without requiring special hardware or proprietary network technologies. The technology resides on standard, unmodified Ethernet infrastructure components.
“The integration of IEEE-1588 into CIP and EtherNet/IP will allow users to take advantage of standard unmodified Ethernet, including standard Ethernet infrastructure, to help solve a whole new group of high-performance applications where hard, real-time performance is required,” said Katherine Voss, executive director of ODVA. “As products become available, ODVA expects to see IEEE-1588 and CIP Sync used with a standard, unmodified Ethernet infrastructure in a wide range of applications – previously the domain of purpose-built, specialty networks – such as robotics, gantries and large-scale conveyors systems.”