Robust Profibus repeaters and industry-grade Ethernet switches used in a tunnel construction project in Sweden.
Laser-controlled boring machines, 120 meters long and weighing 1,000 tons, were used to excavate tunnels 8 meters in diameter, and assemble 6-ton concrete segments with millimeter precision.
The TBMs were controlled from a cockpit near the front of each machine. A Profibus connection was used to transmit control data to a control room outside the tunnel. Communication data was transmitted to a center above ground via Ethernet. Fiber optic cables were of decisive importance in ensuring the reliability of these connections. This is because optical signals are immune to interference from the high-voltage electrical cables that were used to supply the motors of the TBMs with up to 4 MW of power.