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.

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. Aside from being open-source, the BiSS Line is also fully compatible with the existing single-cable infrastructure, including cables, connectors and transmission technology. Using the RS-485 half-duplex physical layer, the BiSS Line protocol provides robust digital feedback with low jitter.

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.

Furthermore, the BiSS Line protocol is 100% compatible with BiSS C. Therefore, 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.

The modular approach and the preservation of all sensor definitions and protocol contents enable sensor manufacturers to easily convert existing BiSS C systems to BiSS Line. Conversion of existing sensor systems to BiSS Line can be done either in the sensor housing, the connectors or the system wiring.

Due to the popularity and availability of RS-485 transmission technology, hardware modification on the drive side is not necessary. The drive can be expanded to be BiSS Line compatible by reconfiguring hardware (FPGA or CPLD) or software, therefore only a firmware change is required. The cables and connectors already available for single-cable use from many manufacturers can be used without modifications for BiSS Line.

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.

First published by EE Times Europe.