"When it comes to servo feedback interfaces, we currently see a low level of compatibility on the market and generally proprietary interfaces. These leave the user little leeway when selecting components and also make them dependent on the development roadmap of individual manufacturers," says Gebhard Kübler, Managing Director of the company of the same name from Villingen-Schwenningen, outlining the status quo in drive technology. With the aim of changing this, the above-mentioned encoder manufacturers are now setting out to bring an open and safe single-cable solution to the market.

Behind 'SCS open link' - SCS stands for Single Cable Solution - is the 'Acuro link' interface originally developed by Hengstler, which is already on the market in version 1.0 and was initially supported by Bosch Rexroth. According to Jochen Feiler, President of Hengstler, the first cooperation talks with Baumer and Kübler took place around two years ago with the result: "Nobody needs another closed protocol that is only driven by one company". Without naming it specifically, Feiler is also alluding to Sick 's 'Hyperface DSL', which until recently was still proprietary. Karsten Just, Managing Director of Sales and Marketing at the Baumer Group, also sees the Waldkirchen-based company's announcement in June that it intends to open up Hiperface DSL to other sensor providers as the first success of the newly formed SCS consortium: "This is exactly what we wanted to achieve, i.e. we are breaking up a monopoly in the field of motor feedback!"

Gebhard Kübler is keen to emphasize that 'SCS open link' is more than just another protocol for displacement and angle sensors. Rather, it is also suitable for integrating other drive-related sensor functions - for example, for recording and transmitting temperature or vibration values for the purpose of condition monitoring. As far as the drive integration of SCS is concerned, there is a corresponding IP core that can be implemented on an FPGA that is usually present in the drive. There are also no license costs on the drive side. On the sensor side, no special hardware in the form of an ASIC is required either - a powerful microcontroller is sufficient to implement the interface.

When asked about the licensing model for other SCS competitors on the part of sensor suppliers, Feiler replies: "We don't want to talk about exact costs in this regard. Just this much: the hurdle is not very high and anyone who does not want to bear these costs has no real interest in the solution!" Gebhard Kübler adds: "In principle, anyone can take part in SCS if they comply with the technical 'rules of the game' - this means, among other things, that the protocol does not allow any variants. We will control this on the part of the founding consortium." The mandatory certification of the relevant components will be carried out by Mesco as an independent body.

The key data of SCS

• supports 2-wire and 4-wire applications
• Enables cable lengths of up to 100 meters
• Functional safety up to SIL3, PLe, category 3
• Transmission rate up to 10 MBaud
• Controller cycles up to 32 KHz
• Electronic Data Sheet (EDS) for encoders (sensors) and motor & drive (actuators)
• Sensor hub: connection for additional sensors (e.g. temperature)