Slip rings transfer power and data from a stationary unit to rotating objects where cables with their fixed connections cannot be used due to movement. Often in the past, such slip rings have helped solve challenges in the design and construction of rotating applications such as turntables. At the same time, their functional principle, which requires permanent electrical contact, is only suitable for the transmission of data to a limited extent: while short interruptions in the power supply usually do not pose any problems, in data communication between controllers they mean delayed or lost telegrams, which lead to errors and, as a consequence, often to plant standstills. Another disadvantage of data transmission via a slip ring is the wear caused by the grinding of the materials against each other.
For pure power transmission, slip rings and rotary unions remain good alternatives. They can be optimally supplemented with radio solutions, for example. As a result, power transmission and data communication are then separated, which has a positive effect on the stability of the solution and reduces EMC interference. As a rule, the combination of slip rings for power supply with radio solutions for data communication is also significantly cheaper than slip ring systems that can simultaneously transmit power and Ethernet protocols such as Profinet. This retrofit ensures a step-by-step modernisation of existing slip ring transmissions without high investment hurdles.
