Depending on the selection of DATAEAGLE radio systems, up to 3000 metres is possible with wireless data communication. With Bluetooth, a range of up to 1000 metres with a line of sight is possible. The 869 MHz and 915 MHz radio technologies are used for longer distances.
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.
The black channel principle allows the transmission of safe and non-safe process data over the same network or bus line. Independent of the regular data transport mechanism used on this line, safety components can transmit data using an isolated safe protocol that tunnels through the underlying network channel. Since safe fieldbuses are pure application protocols without their own physical properties, the available bandwidths and cycle times depend on the data transport protocol used. Possible transmission errors are known and listed in the relevant standards IEC 61784-3 and IEC 61508.
What does this mean for PROFIsafe?
The PROFIsafe protocol has no repercussions on the standard bus protocols. It is intended to be as independent as possible of the respective transmission channel, whether copper cable, fibre optic cable, backplane bus or wireless. Neither the transmission rates nor the respective error detection play a role.
For PROFIsafe, the transmission channels are merely “black channels”. The DATAEAGLE 3732 and DATAEAGLE 4732 wireless PROFISAFE data radio systems were specially developed for the wireless transmission of PROFIsafe via Bluetooth. The use of the patented filter technology guarantees a stable, reliable radio connection, without bus errors in your PROFIsafe applications.