When people talk about Industry 4.0, the term predictive maintenance usually comes up quickly. Predictive maintenance is probably the technology that promises the greatest application and benefit potential in the digitalized factory. It takes the place of reactive maintenance, in which a part is replaced when the machine is already failing. However, this can be expensive if an entire production line comes to a standstill. This is why parts are often replaced prophylactically even though they are still working, which is a waste of money. Predictive maintenance, on the other hand, uses sensor data to draw conclusions about the actual ageing of the part and to calculate the best time to replace it. There are also already solutions for connection systems, but they are not particularly convincing. They either require special cables with a sacrificial wire or two boxes that are docked at the beginning and end of the line. "We wanted to offer a solution that reports before a line fails and without these disadvantages," says Guido Ege, Head of Product Development and Management at Lapp. "We want to make factories smarter, more reliable and more transparent, and practical solutions for predictive maintenance are key to this."

Ethernet cables particularly suitable
Guido Ege's team started with industrial data communication cables, an important growth area for Lapp. Ethernet cables have a complex structure and exhibit special fault characteristics due to their high-frequency properties, making them particularly suitable for such a prognosis. The gradual ageing process begins with a broken shield, which leads to increased EMC interference. If the strands break, the attenuation increases and the data rate decreases; if the core breaks completely, communication finally fails altogether.

The aim was to calculate the optimum replacement time for a line in advance and thus to plan the time of replacement in such a way that production is disrupted as little as possible. The expected service life is calculated from the changes in the actual transmission properties and can vary for the same type of cable. However, Ethernet cables are just the beginning. In the next step, live cables will also be monitored.

No sacrificial cores necessary
One advantage of Lapp's measuring principle is that no changes to the cable structure are necessary, so no additional measuring or sacrificial cores are required in the cable. The prediction is based solely on a protocol and a special algorithm. The installer can therefore connect the cables as usual and does not need to connect any additional sacrificial cores. This also makes it possible to retrofit existing systems.