Robots continue to gain ground within automated manufacturing. While they used to be predominantly found in the automotive industry, robots are now increasingly penetrating other sectors and supporting the automation of manufacturing processes. Today, robots are an integral part of the symbol of a modern factory. They are no longer just performing monotonous motion sequences, but also provide access via the connection to the data network, which is required for process monitoring or remote maintenance, for example. Industrial protocols such as Profibus and Profinet are used to ensure seamless data communication of the feedback loops between the sensors on the robot arm, the robot system, the controller and its connection to the control level. The cabling required for network communication is carried out using flexible Etherline data cables.

However, the rapid movement sequences of the robot arms in three-dimensional space place a great deal of mechanical stress on the cabling, from the commissioning of the robot to the last cycle completed. This puts Ethernet data cables in particular to the test: with a twisted pair structure of the wires, double shielding and transmission parameters that are critical for successful data communication, these are among the more technically demanding cables.

Designers of robot applications often have to choose between data cables that are designed either for linear, horizontal travel paths - as typically found in drag chains - or for torsional motion sequences. The main reason for this is the different internal structure of the cables. Lay lengths within the wire pairs must be precisely maintained and coordinated. Adjacent wire pairs must not interfere with each other and interference signals must be prevented. While cables and wires for horizontal travel preferably have relatively short lay lengths in order to achieve smaller bending radii in the drag chain, long lay lengths are the preferred choice for torsion cables. The problem: In their motion sequence, robot applications combine horizontal linear movements with torsional loads. Many common Ethernet cables are not able to withstand this combined load to a sufficient degree.

Uniform industry standard type R

The challenge of a sophisticated cable design is compounded by the fact that no uniform industry standards for robot-compatible Ethernet data cables have been agreed to date. As a result, there were numerous, uncoordinated and proprietary understandings of "robot suitability" for Ethernet cables on the market. The Profinet user organization addressed this situation and developed the necessary specification in close cooperation with the AIDA (Automation Initiative of German Automobile Manufacturers). The stringent requirements for Profinet type R data cables were developed in an exchange between leading companies in the field of industrial cabling. Not only were well-known manufacturers involved in the development process of the new guideline, but opinions and suggestions from users were also taken into account. Lapp was also involved in the development of the new industry standard from the very beginning. The new, so-called "Type R" describes 2-pair Cat.5e industrial data cables, which must withstand numerous electrical and mechanical requirements and guarantee a long service life when used with industrial robots. In the current version of the "Cabling and Interconnection Guideline", version 4.11, type R is now included for the first time alongside the common cable types type A (fixed installation), type B (occasional moving use) and type C (drag chain and special applications).