CANWAY has completed the development project “CW-131 Optical Transmission Unit” together with a large automotive OEM. The requirements to be resolved included bidirectional transmissions across whole bus systems such as FlexRay, CAN, LIN, and Ethernet over long distances up to 500 m. Amongst others, it is used to network approval tests of control units on HiL test benches. With the module CW-131 created in the project it is possible to couple a total of 6 CAN buses (4 high speed, 2 low speed), 4 FlexRay™ buses (channels A and B respectively) and 2 LIN buses. The most challenging aspect in this case was networking FlexRay™ due to the deterministic architecture of the fieldbus system and its time-critical requirements. Line lengths beyond 250 m have already been tested with the solution developed by CANWAY. This sees a fibre-optic cable with a maximum of 6 fibres deployed (2 fibres each for FlexRay™, CAN and LIN, and Ethernet).

The CW-131 is used to exchange data between HiL subsystem test benches. This functionality makes it possible to test vehicle subsystems, e.g., drivetrains as well as chassis and suspensions in combination without having to depend on close spatial proximity. In addition the concept of the CW-131 includes galvanically isolated connections between both subsystem test benches.

The next feature to be implemented during the course of further developing the “Optical Transmission Unit” will be to couple BroadR-Reach Ethernet. The transmission of analog and digital signals as well as the implementation of signal filters, such as for the CAN bus are in planning. Signal filtering would make possible the selective transmission of messages from one system to another.

The CW-131 is offered as a complete system in a 19” housing. Decoupling of bus systems or customer-specific flavours are possible for example for CAN and LIN, FlexRay and Ethernet.