Object Directory - Structure

All the CANopen objects relevant for the Bus Coupler are entered into the CANopen object directory. The object directory is divided into three different regions:

  1. communication-specific profile region (index 0x1000 – 0x1FFF).
    This contains the description of all the parameters specific to communication.
  2. manufacturer-specific profile region (index 0x2000 – 0x5FFF).
    Contains the description of the manufacturer-specific entries.
  3. standardized device profile region (0x6000 – 0x9FFF).
    Contains the objects for a device profile according to DS-401.

Every entry in the object directory is identified by a 16 bit index. If an object consists of several components (e.g. object type array or record), the components are identified by an 8-bit sub-index. The object name describes the function of an object, while the data type attribute specifies the data type of the entry. The access attribute specifies whether an entry may only be read, only written, or may be both read and written.

Communication-specific region

All the parameters and objects necessary for the CANopen Bus Coupler’s communication are in this region of the object directory. The region from 0x1000 to 0x1018 contains various general communication-specific parameters (e.g. the device name).

The communication parameters (e.g. identifiers) for the receive PDOs are located in the region from 0x1400 to 0x140F (plus sub-index). The mapping parameters of the receive PDOs are in the region from 0x1600 to 0x160F (plus sub-index). The mapping parameters contain the cross-references to the application objects that are mapped into the PDOs and the data width of the corresponding object (see also the section dealing with PDO Mapping).

The communication and mapping parameters for the transmit PDOs are located in the regions from 0x1800 to 0x180F and from 0x1A00 to 0x1A0F.

Manufacturer-specific region

This region contains entries that are specific to BECKHOFF, e.g.:

  • data objects for special terminals
  • objects for register communication providing access to all the Bus Couplers’ and Bus Terminals’ internal registers
  • objects for simplified configuration of the PDOs

Standardized device profile region

The standardized device profile region supports the device profile of CANopen DS-401, Version 1. Functions are available for analog inputs that can adapt communication in the event-driven operating mode to the requirements of the application and to minimize the loading of the bus:

  • limit value monitoring
  • Delta function
  • activation/deactivation of event-driven mode