Single-cable motor interface goes open-source

January 11, 2017 // By Julien Happich
The open BiSS Line protocol (Bidirectional, Serial and Synchronous) aims to provide a universal, robust, and effective solution for all manufacturers and users of electrical drive systems. Since its launch in 2002, BiSS has established itself worldwide as an open, standardized sensor interface. The BiSS user community has been working on single-cable technology since 2014 and presented the BiSS Line protocol as the first open interface for single-cable technology at the 2016 SPS IPC Drives exhibition in Nuremberg, Germany.

Digital feedback in the same cable and using the same connectors as motor power is a current trend in electrical drive systems. This single-cable approach simplifies system wiring and makes installation and maintenance easier. These advantages have already attracted the interest of both users and manufacturers. The technical challenges of single-cable technology have been solved and proprietary products are already available in the market. However, proprietary protocols limit the diversity of manufacturers and solutions by making interconnectability difficult or impossible. Thus, competitive products from different manufacturers are slow to appear.

As well as being open-source, a decisive advantage of BiSS Line is its full compatibility with the existing single-cable infrastructure, including cables, connectors, and transmission technology. Using the well-established RS-485 half-duplex physical layer, the BiSS Line protocol provides robust digital feedback with low jitter. A 4-wire solution with separate communication and supply lines or a 2-wire solution with combined communication and supply is available.

The optional Forward Error Correction (FEC) provides even more robust data transmission. In addition, the open BiSS Line protocol provides higher noise immunity when transmitting the position capture time, which is encoded and includes error correction.

Furthermore, the BiSS Line protocol is 100% compatible with BiSS C. This means that all existing BiSS definitions such as electronic data sheets (EDS), user data memory (USERDATA), BiSS profile definitions, ID and serial numbers, etc. can be re-used, accelerating integration of BiSS Line in both sensors and drives. Even BiSS Safety solutions can be implemented directly using BiSS Line. All BiSS Safety contents are covered by the BiSS protocol and are transferable via BiSS Line.