CAN Application Layer & CANopen
CAL stands for “CAN Application Layer” and was originally developed by CAN in Automation (CiA). The CAN Application Layer is divided into several parts, for example:
- CMS (CAN-based Message Specification) which defines protocols for transferring data between CAN modules
- NMT (Network Management Service) which defines the protocols for system startup and shutdown, error logging, and more
- DBT (Distributor Service) which defines a protocol for distributing identifiers to the different modules in a system
CAL is clearly influenced by the OSI model. CANopen is essentially a subset of CAL combined with a set of profiles, which are not yet finalized. CAL/CANopen is one of the currently four higher layer protocols supported by CiA. Both the CAL and the CANopen draft specifications are available from CiA.
More information about CAN in Automation.
Watch the update on “CANopen FD”, presented by the CAN in Automation group.