Entering new dimensions with ASi-5

For more than 20 years AS-Interface has been setting ever newer standards in the efficient networking of sensors and actuators through permanent optimization. With the introduction of ASi-5 this global leading system at the automation base now sets the course to the next dimension of digitalization. In fact, significantly involved in this future-oriented development has been the same company that also introduced the first certified ASi master back in 1994: Bihl+Wiedemann.


Hollywood legend Billy Wilder is known as the originator of some good witticisms, one of which applies perfectly to the dramaturgy of the success story of AS-Interface: “You have truly written the script to absolute perfection“, the multiple Oscar winner is said to have remarked to one of his authors. He then left the author stunning by adding the following sentence: “And now we will make it better“.


In a figurative sense this is exactly what has happened several times during the 20-year history of AS-Interface. ASi has always remained true to itself – while at the same time becoming ever more powerful. Otherwise, the breathtaking triumph of the system would have been hardly imaginable. In the meantime, there are 37 million standard devices and 8 million safety devices in use, with more than 2000 certified products for all kinds of applications – mainly in factory automation, material handling and building automation.

The typical yellow cable is and will always be a symbol of efficiency

When the system came on the market in the mid-1990’s, there was at first of course little to nothing that one could have done to improve it. Up to that point actuators and sensors had to be wired cumbersomely in parallel – and suddenly there was a bus available that transported both data and power on one single cable, that offered absolute freedom of topology, and that could be easily integrated into higher level fieldbuses. Moreover, the system offered cost-effectiveness, simple installation and operation as well as flexible possibilities for expansion. The typical yellow cable quickly became a symbol of efficiency, and AS-Interface quickly became de facto standard around the world on the lowest level of automation.


In safety technology as well AS-Interface represented a true quantum leap: With ASi Safety at Work it has been possible since around the turn of the millennium to transmit both safe and non-safe signals on one and the same cable. Now the last bastion of anachronistic parallel wiring was finally being displaced. The trade magazine IEE celebrated the clearing of cost-intensive cable forests as a “clear cutting in safety technology.”


The typical yellow cable is and will always be a symbol of efficiency While AS-Interface was conquering production plants on every continent in fast-motion, the simplest bus system in the world was at the same time being continually optimized. By the mid-2000’s the International Association of ASi manufacturers took one of the greatest technological steps with their innovation step 3.0, which among other things enabled improved node profiles. But even independent of new specifications development proceeded at a rapid pace: Now the user had for instance ever more diagnostic capabilities and ever more intelligent networking options. And the range of gateways with which two complete ASi networks can be incorporated into the higher level fieldbus - as easily as a completely normal module - became ever greater as well.

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Fig.: Comparison of ASi networks before and with ASi-5

With a sustainable evolution leap into the digital future

Not least for these three aspects the name of that company which brought the first certified ASi master to the market at the beginning of the AS-Interface era gained focus with regularity: Bihl+Wiedemann. Thus, it is no coincidence at all that the automation specialists from Mannheim are now also playing an essential role in the development of the technological strategy of the future from the very beginning. Together with many well-known manufacturers of AS-Interface and three leading research institutions Bihl+Wiedemann first became involved in a project which ended in the decision to further develop AS-Interface into ASi-5. The manufacturers of AS-Interface recognized that a sustained evolutionary leap would be called for to make the most widely used system for automation ready for the future. This insight already came at a time when modern Ethernet solutions were gaining ever more ground in automation technology, the call for more data through smart sensors got louder and – although the keyword hadn’t yet been invented – developments related to the digitalized factory of tomorrow were picking up speed towards the vision of industry 4.0.


A glance at the first strategic cornerstones of the developing technological concept shows how much foresight the project group founded back then brought to their task. The fact that the digital transformation increasingly accelerated the pace over the succeeding years still changed nothing in the basic considerations of those ASi-5 pioneers. Beyond dispute from the very outset was for example the requirement that the unique character of AS-Interface had to remain intact even with the next step of innovation: its simplicity, ruggedness and its economy just as much as the superior electromechanics, the freedom of topology and the interoperability. And of course the backward compatibility within the system: it had to be ensured, in other words, that the current and new ASi components would work together on one and the same cable and in one and the same network.

Intensive development work for absolute security of investment

Consensus was also quickly found in defining the levers that needed pulling in order to optimally prepare AS-Interface for the digital future. In addition to improving the capabilities of integrating IO-Link sensors, increasing the data bandwidth and maximum number of nodes as well as shortening the cycle times became the focus. Furthermore, the new ASi masters should be able to poll their nodes simultaneously and not one after the other.


Once the involved companies under the technical leadership of Bernhard Wiedemann, Managing Director of the AS-Interface Masters from Mannheim, had invested several years of intensive development work in the next generation of the market-leading system at the automation base, the first operable test setup was presented at the members assembly of the AS-International association in December 2016. External publication finally followed at the fair SPS IPC Drives 2018 in Nuremberg – under the motto “ASi-5 – The Shuttle to Digitalization”. This is perhaps the most important message that AS-Interface sends to its users with this premiere: regardless of what demands will be placed on the smart factory of tomorrow – thanks to ASi-5, AS-Interface with its increased performance, more intelligent communication and increased flexibility will in any case remain the perfect shuttle bus from the actuator and sensor level to all higher level interfaces, providing absolute security of investment into the age of the digital conversion.