Networking your ECUs into a system

Step 3: Configure the system

Key tasks in configuring a CANopen system are:

  • Configure the PDOs (COB-ID, mapping, transmission type)
  • Define a NMT master
  • Define the NMT slaves and assign them to the NMT master
  • Define a configuration manager
  • Define a SYNC producer
  • Set up a node monitoring mechanism (Guarding or Heartbeat)

A CANopen device always saves configuration data of any type in an object provided for this purpose – the object directory. Of course, a suitable configuration tool is essential for configuring these objects. Good tools support you here by providing specialized input masks and computing process data objects (PDOs).

Whether a CANopen device is even configurable depends on the type of device implementation. CANopen devices can be subdivided into two device classes here:

Devices with fixed configuration There is a clear definition of which process data (e.g. digital inputs or momentary engine speed) should be transmitted when and with which CAN message. These settings cannot be changed at a later time. Often, devices with fixed configurations are less expensive than devices of identical construction that enable device configuration during operation. This is due to the significantly simpler software structures and resulting transparent device implementation.
Configurable devices These devices must be configured before startup. All device parameters are defined with a suitable configuration tool (such as ProCANopen). Afterwards, the resulting configuration is saved in the device.

Step 4: Save the configuration in the system

The network configuration created with the configuration tool is now saved in the configurable devices, provided that the devices support "non-volatile" storage (configuration data are not lost in a restart) of the configuration data. As an alternative, the device configuration can be saved in a Configuration Manager, which executes the configuration of configurable devices at the system start. The Configuration Manager must already be defined in the framework of the network configuration. This approach enables simple replacement of a defective device by a new device of identical construction (ease of system maintenance).

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