BISS-C Receiver


BiSS is an open-source digital interface for sensors and actuators introduced by iC-Haus GmbH in 2002. BiSS stands for bidirectional serial synchronous — it is a high speed serial synchronous bi-directional full-duplex communication protocol compliant with RS-422/485 standards. BiSS-C mode is the continuous mode in which the BiSS-C receiver reads out the position data cyclically.  

CouthIT’s BiSS-C receiver implementation interfaces with BiSS-C encoders connected in point-to-point or in daisy-chain/bus topology. BiSS-C encoders provide high resolution absolute single turn and multi-turn position data along with status information. The BiSS protocol is used on the lower sensor/actuator communication level in industrial applications (e.g. motor feedback, robotics) which require high-speed data transfer rates, safety, flexibility and a minimized implementation effort. BiSS can address internal registers (via Control Communication) in the encoder that can be read by and written to by the BiSS-C Receiver with data about the encoder itself (identification, device data, resolution, etc.). The interface enables a complete closed-loop position control system by providing the real-time position feedback to the master to control the motor.

CouthIT’s BiSS-C receiver implementation has support for BiSS Safety profile as well. BiSS-C safety profile has been certified by TÜV Rheinland for safety-critical applications up to SIL3 according to IEC61508:2010. BiSS Safety uses the concept of a “Black Channel” transmission and specifies the data channel contents in order to ensure failure mode detection as defined in IEC61784-3 using redundant position words, different CRC polynomials and a sign-of-life counter. BiSS Safety is fully compatible with BiSS and all of its features including line delay compensation, processing times and daisy chaining of additional sensors.

Salient Features
  • Support for point-to-point and bus/daisy-chain communication.
  • Support for baud rates from 1 MHz, 2 MHz, 5 MHz, and 10 MHz.
  • Support for point to point and maximum of 3 encoders connected in daisy-chain.
  • Support for control communication for Register read and write access.
  • Support for processing delay compensation and line delay compensation.
  • Support for concurrent multi-channel support on a single PRU (up-to 3 channels with identical number of encoders of same frequency connected to all configured channels).
  • Support for multi-channel with different number of encoders connected across channels under load share model (this feature is specific to TI ICSSG wherein each of PRU, RTU-PRU, and TX-PRU from one PRU-ICSSG slice handles all 3 channels).
  • Support for Time triggered/Contineous mode cycle trigger operation.
  • Support for BiSS safety profile.
  • Support for 100 meter cable lengths depends on baud rate.
  • Support for 6-bit CRC for position data, 4-bit CRC for control communication data and 16-bit CRC in case of Safety profile.
Testing Features
  • Tested using 12-bit iC-Haus encoders, Wachendorff encoder, and 46-bit (single + multi turn) Higen encoders.
  • Tested for baud rates 1 Mhz, 2 MHz, 4 MHz, and 10 MHz.
  • Tested for absolute position data requests and register read and write using control communications.
  • Validated for safety and reliability with CRC checks as specified by the Standard.
  • Tested with 1 encoder connected in a point-to-point communication setup.
  • Tested with 3 encoders connected in a daisy-chain configuration.
  • Tested with up to 3 encoders connected in a bus.
  • Tested for multi-channel communication modes by simultaneously connected encoders to different PRUs in the ICSS.
Available Platforms

TI AM243x, TI AM64x, TI AM263x and TI AM437x

For resource requirements & other details