Welcome to Ars-Informatica  


If you want to build a ship don't herd people together to collect wood and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea. (Antoine-Marie-Roger de Saint-Exupéry)


CANopen also uses multiple definitions involving the term "object". There are objects such as Object Dictionaries (OD), Process Data Objects (PDO), Service Data Objects (SDO) and Connection Objects (COB), among others.

  • The Object Dictionary’s primary function is to store variables and constants, both process data and configuration data, in some sort of look-up table. The Object Dictionary is described here.
  • Process Data Objects are messages (or frames) that contain process data.
  • Service Data Objects are messages (or frames) that contain service/configuration data.
  • COB IDs are used whenever a message (or frame) needs to be assigned to implement a service. For example, each SDO requires the assignment of two COB IDs: one for the client sending requests to the server and one for the server sending responses back to the client.