A CAN bridge can connect CAN networks of different bit rates or protocols with each other. It is based on the store-(modify)-forward principle where CAN messages are received by a sub-network and then transmitted to the other sub-network.
Translation and filter rules can also be used, allowing a protocol adaptation to be carried out between the sub-networks. A bridge can also provide simple gateway functions.
Unlike the CAN repeater, the CANbridge enables the enlargement of the maximum network size so that the sub-systems are fully self-sufficient with regard to bus arbitration. Independent of each other in terms of their real-time behavior, CAN sub-networks connected by bridges are to be regarded as independent networks.
CAN bridges are appropriate for creating hierarchical networks by transferring only the information to the connected sub-networks via bridges which are relevant to the sub-network. The bridge function can also be executed with the aid of other transmission systems. For example, the CAN-Ethernet-CAN bridge is connected via two Ethernet-TCP/IP gateways which enable connection to remote CAN networks.
As an extension to the CAN bridges, CAN gateways allow for access to CAN networks via other communication systems. In each case, the protocols of the connected bus systems are mapped to the other communication model.
This allows devices with only one serial port to be connected to CAN/CANopen networks via CAN/CANopen-RS232 gateways. Gateways can also provide remote accesses to CAN networks. The CAN-TCP/IP gateway, for example, enables worldwide access to the CAN network for both diagnosistic and service purposes.
Connection of CAN networks with the CANbridge