Phoenix Contact calls Axioline ‘world’s fastest I/O system’

Are your I/O too slow? The Phoenix Contact real-time Axioline I/O system represents a "rethinking classical serial bus I/Os" with design inspiration from information technology and telecommunications, according to Roland Bent, executive vice president, Phoenix Contact GmbH & Co. KG. Bent made the comments at his company’s press conference at the SPS/IPC/Drives show in Nürnberg, in November 2009.

"We went back to the fundamental principle behind I/O systems, since, even in the era of Ethernet, users of these systems are usually not concerned with sophisticated high-tech solutions. Instead, they want to be able to conveniently connect devices and transfer the associated signals from A to B. This is a topic that has concerned Phoenix Contact since its earliest beginnings in the 1920s and now forms the basis of our terminal block concept," said Bent.

Fast and simple

The terminal block is a universal electrical connector. It has been successful over the years because it addresses three core user needs. It is simple, it is robust and it is fast; in other words, it does not affect the time response of the system in which it is used.

"Put simply, it is invisible to the electrical and mechanical response of the automation system. Therefore, it does not add to the complexity of the system," said Bent. "After the paradigm shift in communication technology caused by Ethernet and other similar innovations, the time has come for a new, revolutionary approach to serial I/O systems. The time has come for a system that is as fast and as simple as the terminal block."

Phoenix Contact has a lot of history in this area, he pointed out, making its first porcelain terminal in 1928, right through to the first modular terminal block system "Clipline Complete," which is still being developed. The company has 25 years of history with fieldbus, with Interbus, starting 1983.

Bent said if an I/O system is going to function like a terminal block, it must provide three central terminal-block attributes: fast, robust and simple.

"Debate around the transfer rates and update times of serial bus systems is as old as the systems themselves," said Bent. "For this reason, the term "real-time" cannot be defined absolutely and its meaning always depends on the requirements of the applications in question."

Idea behind the Axioline concept is to make the system so fast, nobody will question whether it’s real time or not, making the real time discussion superfluous. Axioline functions in real-time regardless of the application with a time response that behaves like direct cabling. The update time of between 500 nanoseconds and one microsecond for every terminal block (depending on I/O configuration), speed corresponds to the physical transfer rate required by an electrical signal to bridge a distance of around 100 m of cable.

For a system with 256 I/O connections, update time is less than six microseconds, which is comparable to a distance of 1,000 m with parallel cabling.

"Deviation between the transfer rate with Axioline and that of parallel cabling is therefore irrelevant. As a result, time is no longer an issue for the user of an Axioline system, because it surpasses all of the limits of today’s existing systems and now achieves fast transfer rates of less than 10 microseconds, a figure that was previously only attained by parallel cabling. We call this real-time I/O."

Each terminal block, which contains up to 64 I/O, comes with its own 32-conductor passive backplane section. Individual backplane sections adjoin to form a continuous piece that fits on a top-hat, or DIN rail.

In the head station (Profinet and Sercos III versions available at first, with more to be added) is a master controller chip, an FPGA. Each terminal block has a slave controller, also an FPGA. All the slave controllers are alike, except for I/O-connection differences. Phoenix Contact expects to replace FPGAs with ASICs, he said.

Robust like a terminal block

Axioline, with emphasis on the electromechanical function of the terminal block, differs in development from electronic devices and modules, said Bent. "Electronics required for the transfer technology or its digital or analogue equivalent and functions is an indispensable addition, which should not affect the fundamental properties of the terminal block," he said. Optimized for electromagnetic compatibility (EMC), the system need no additional electrical shielding. Designed to handle a continuous shock of at least 10 g, the shock and vibration resistance is identical to that of a terminal block. It has a standard operating temperature range of -25 °C to +60 °C, greater than most electronic devices.

Simple like a‘Clipline’ terminal block

Axioline, like the Phoenix Contact‘Clipline Complete’ terminal block system, has a familiar gray color, rather than the usual bright green Phoenix color. The modules-or terminal blocks as Phoenix Contact people call them-can be assembled without tools, with a snap-fit. The terminal block can be exchanged, while the wiring is installed using pluggable terminals, so that the user has the option to exchange the entire block or just the I/O connections. It can be labeled using the same materials as the Clipline Complete system. www.phoenixcontact.com/terminal-blocks/26840.htm

The field connection technology used is the familiar push-in technology (PIT). Rigid conductors and conductors with ferrules can be inserted directly. For slim, flexible cables, the terminals are equipped with an appropriate opener that is operated with a screwdriver. Power is supplied via a power terminal in each block, which makes calculations of load combinations unnecessary.

At a height of 50 mm, Axioline terminal blocks are also mechanically compatible with modular terminal blocks. In addition, they are suitable for standard control cabinets with a flat width of 80 mm and can be combined with installation aids such as crest rails. The terminal blocks have a width of 54 mm and, for smaller pitch widths, 32 or 18 mm. Up to 64 terminal points are currently possible on a width of 54 mm. This enables 16 digital inputs and outputs to be connected using four-conductor technology or 64 digital inputs using single-conductor technology.

The first Axioline bus coupler is equipped for Profinet RT and IRT, and Sercos III. Additional bus couplers will follow. It also may be coupled with a PC-based, high-speed controller, for example, Phoenix’s new Soft SPS.

Bent said future processor platforms within the Axioline system may perform regulation and controller tasks as integrated, decentralized high-speed controllers. Smaller modules, even down to single I/O signal forms will be available shortly. And terminal blocks are becoming increasingly effective and user friendly, which will enable a software configuration of the I/O signal forms.

"New functions, with regard to I/O configuration and signal support, for example, will become available in a variety of forms in the coming months and years," he said, including various functional modules and safety solutions.

"The Axioline architecture even allows the system to develop in the direction of process engineering applications, such as a hot-swapping function," Bent said.

For more about Phoenix Contact financials, and two additional product images, see the Control Engineering Europe Phoenix Contact Axioline story .

Also see, from Control Engineering :
– Terminal blocks provide safe disconnect when current transformer short ; and
– Fast, flexible terminal blocks .

– Michael Babb is editor, Control Engineering Europe , www.controlengeurope.com; edited by Mark T. Hoske, editor in chief, Control Engineering , www.controleng.com.

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