EtherCAT Device Identification

The Device Identification feature provides explicit identification of an EtherCAT SubDevice. This is an optional feature and is not required for network operation.

Note: The device identification feature is often poorly documented by SubDevice manufacturers and is not supported by all SubDevices. It may be difficult to determine from the documentation whether it is supported. Search for terms such as Station Alias, Identification, and Fixed Address.

On an EtherCAT network, the MainDevice automatically assigns Station Addresses to the SubDevices based on their positions in the network (also known as auto increment address). Station Addresses do not explicitly identify a certain SubDevice. For example, a SubDevice with a Station Address of 1005 can be removed and replaced with another identical SubDevice and that replacement SubDevice will have a Station Address of 1005 as long as the position in the network is the same.

The Station Address is very useful for easy replacement of devices. However, if cables are accidentally reconnected to identical devices in the wrong order, the EtherCAT network will not be aware of the mix-up.

The EtherCAT Device Identification feature solves this problem by identifying specific SubDevices so that a wiring error will result in a network mismatch and the SubDevices will not enter Op mode, preventing operation.

Device ID Data Location

The Device Identification is stored in the EtherCAT Slave Controller (ESC) registers (these are different from the CoE Object Dictionary address locations). In the EtherCAT Editor, on the Advanced Options tab, this location is listed in the Select Local Address box. The SubDevice’s ESI file automatically populates this box based on the identification method it supports. The address may be one of the following:

For SubDevices with physical switch settings, the value is typically 0x0134.
For SubDevices with software configuration, this value is typically 0x0012 and the Device ID is called the Station Alias.
For older SubDevices, whether physical switches or software configuration, the value may be something else, commonly 0x1000, but could be some other value.

A value of 0x0012 does not necessarily mean that device identification is supported, rather it is also the value that will be populated if device identification is not supported.

Device Identification must be enabled in the EtherCAT Editor, on the Advanced Options tab. Depending on the method employed, the Device ID value may also be entered. Device ID changes require a power cycle afterwards.

After setting the Device ID, the actual ID of the SubDevice may be viewed in these ways:

In the EtherCAT Network Mismatch Analyzer, in the Network Device ID column.
If the SubDevice uses address 0x0012 (or possibly 0x1000), the Device ID is visible in the EtherCAT Diagnostics, on the ESC Register tab of the SubDevice. Expand the 0x0012 Index to view the Device ID value.

Setting the Device Identification

Important! Device Identification via software configuration (using the Write to EEPROM) will only work for SubDevices that have been added to the network using Configure Using Network Scan. It will not work for SubDevices added manually in the EtherCAT Explorer, or added via the Edit Topology dialog. Configure Using Network Scan deletes the network and creates a new one, meaning that all SubDevice configuration settings are lost. Therefore, if you plan on using Device Identification via software configuration, make sure to create your entire network at the beginning via Configure Using Network Scan.

Setting the device ID involves two main steps:

Set the value in the SubDevice

This may be via physical switches, writing to the EEPROM from the EtherCAT Editor, or setting it in the SubDevice’s configuration software.
Configure the network to expect that value

In the EtherCAT Editor, you must enter the same device ID so that the network will expect it. If the value the network expects (configured device ID) does not match the actual value in the SubDevice (network device ID), the SubDevice will not enter Op mode, preventing operation.

Follow the instructions below depending on the method.

Setting Device ID via Physical Switches on the SubDevice

To set the explicit device identification via switches on a SubDevice:

Set the switches to your desired value according to the SubDevice manufacturer’s documentation, then cycle power to the SubDevice. The ID values do not need to be unique, but it is normally desirable to set them to unique values.
In the EtherCAT Editor, select the SubDevice.
On the Advanced Options tab, check the Check Identification checkbox.
In the box below Check Identification, enter the same identification number that you set the switches to.

You typically do not need to change the Select Local Address value. The SubDevice’s ESI file automatically populates this box based on the identification method it supports. For physical switch settings, the value is typically 0x0134.
Download the EtherCAT configuration.
Verify the settings as follows:
1. In the EtherCAT Diagnostics, in the toolbar, click the EtherCAT Network Mismatch Analyzer button.
2. The Network Device ID column contains the identification value of the SubDevice as set by the switches.
3. The Config Device ID column contains the identification value of the SubDevice as you entered it in the RMCTools project.
When Identification Checking is enabled, the Network Device ID and Config Device ID must match when the network starts up, or the SubDevice will not enter Op mode.

Setting Device ID via Software Configuration in RMCTools

This method will only work for SubDevices that have been added to the network using Configure Using Network Scan. It will not work for SubDevices added manually in the EtherCAT Explorer, or added via the Edit Topology dialog. Therefore, if you plan on using Device Identification via software configuration, make sure to create your entire network at the beginning via Configure Using Network Scan.

To set the explicit device identification for a SubDevice in RMCTools:

In the EtherCAT Editor, select the SubDevice.
On the Advanced Options tab, check the Check Identification checkbox.
In the box below Check Identification, enter an identification number. This can be any number you choose, up to 65,536. The ID values do not need to be unique, but it is normally desirable to set them to unique values.
Click Write to EEPROM.

Note: If the Write to EEPROM button is grayed out, you cannot used this method. This method only works if the SubDevice was added to the network using Configure Using Network Scan.
You typically do not need to change the Select Local Address value. The SubDevice’s ESI file automatically populates this box based on the identification method it supports.

Setting Device ID via SubDevice Configuration Software

If the SubDevice has configuration software that supports setting the EtherCAT device identification, consult the manufacturer’s documentation for instructions.

After setting the device identification, you can view it as follows when it is in the EtherCAT network:

Set the device ID in the SubDevice’s configuration software according to the manufacturer’s documentation. The ID values do not need to be unique, but it is normally desirable to set them to unique values.
In RMCTools, go online with the RMC.
In the EtherCAT Editor, select the SubDevice.
On the Advanced Options tab, check the Check Identification checkbox.
In the box below Check Identification, enter the same identification number that you configured the SubDevice to.

You typically do not need to change the Select Local Address value. The SubDevice’s ESI file automatically populates this box based on the identification method it supports. For physical switch settings, the value is typically 0x0134.
Download the EtherCAT configuration.
Verify the settings as follows:
1. In the EtherCAT Diagnostics, in the toolbar, click the EtherCAT Network Mismatch Analyzer button.
2. The Network Device ID column contains the identification value of the SubDevice as set by the switches.
3. The Config Device ID column contains the identification value of the SubDevice as you entered it in the RMCTools project.
When Identification Checking is enabled, the Network Device ID and Config Device ID must match when the network starts up, or the SubDevice will not enter Op mode.