Identifying E-CAT SubDevices on the EtherCAT Network

E-CAT SubDevices, such as drives or I/Os, are connected to an E-CAT MainDevice on an EtherCAT network. To identify multiple SubDevices on the network, you can use the SubDevice Index, Explicit ID, or Station Address. Each serves a distinct purpose depending on your application needs.

SubDevice Index

The SubDevice Index is automatically assigned by the MainDevice when the EtherCAT network starts, based on the physical connection order. The first device connected directly to the MainDevice is assigned Index 0, followed by Index 1, Index 2, and so on. These indexes remain consistent within the E-CAT SubDevice array even if devices are added, removed, or reconnected. For more details, see wRTOS E-CAT Hot Connect, AutoRepair, AutoRestart. To retrieve a SubDevice's Index, use RtecatGetSubDeviceStatus.

SubDevice Explicit ID

The Explicit ID is a preconfigured address used to differentiate same-model SubDevices on the same network. It must be set before adding the device to the network, either via a rotary DIP switch on the device, or through the device’s configuration tool. To retrieve a SubDevice's Explicit ID, use RtecatGetSubDeviceStatus.

SubDevice Station Address

The Station Address is an alias address stored in the SubDevice’s EEPROM. Its configuration is device specific. Please refer to the device's user manual for details. This address persists after power-off and is independent of the device’s physical position on the network, making it useful for distinguishing identical devices in specific roles, e.g., X, Y, and Z axes. To retrieve a SubDevice's alias address, use RtecatGetSubDeviceStatus.