04.11.02 Introducing the BiSS Interface
Nov, 2002: Finally an open digital interface for drive systems.
From sensor to control, the bidirectional digital sensor interface, BiSS, now performs the data transmission with an open protocol. It can simultaneously transmit the measured values of up to 8 additional sensors. iC-Haus GmbH in Bodenheim, Germany, provide master and slave devices and, furthermore, make their know-how available under the BiSS licence.

The BiSS concept includes that process information is directly digitized in the sensor. Firstly, this guarantees high interference immunity, and secondly, analog interference suppression filters at the receiving side, e.g. within a drive, will not be required. Bandwidth and dynamics of signals are available to their full extent.

Moreover, it is remarkable how the use of BiSS economizes electronics on the transmitting and receiving side, namely quite expensive analog drivers and receivers as well as bidirectional driver components on both sides for the sensor parameterization. Additionally, the serial data transmission concept ensures a reduction of the lines and, as a result, allows to use less expensive connectors. Using BiSS helps to decrease design costs during the development and to decrease the board space requirement for electronics. This meets the persistent trend towards more and more compact type designs.

The BiSS protocol does not prescribe the format of the sensor data. As a result, users such as manufacturers of sensors and controls very flexible with regard to the implementation of their ideas. Minimal declarations are only required for register data for the paramaterization if an adaptive master needs to be supported. The BiSS protocol controls when and what datum has to be sent or received. The process is defined through time conditions, which are transmitted together with the clock.

Operational parameters are available in the memory area of the slave ICs. Furthermore, there are system parameters and in addition, should the occasion arise, so-called OEM parameters that can be defined by the users. This also means that the sensor interface BiSS already meets the requirements for an electronic type label. In addition, the storage of temporary system data is conceivable in this area, e.g. the software-defined zero point of a rotary encoder. The data transmission is protected through a cyclic redundancy check (CRC). This means that each data packet is provided with a check sum, which is evaluated by the receiving device.

Specific designs of individual users are not required to be compatible with other BiSS products and, as a result, not restricted or made unnecessarily expensive. Users can reserve own blocks of ID numbers and also maintain these without an agreement with other users. On their own they provide their customers with correspondingly matched drivers.

BiSS users do not have to register anywhere. Only when users intend to market and to pass on own solutions with BiSS should these be registered and disclosed to preserve the transparency of the BiSS concept in the long term.

With BiSS the manufacturer iC-Haus offers an open digital sensor interface under the BiSS licence for the individual solution of various tasks.