ESI and ENI Files

The EtherCATClosed***EtherCAT is an open, high-performance Ethernet-based fieldbus system. The development goal of EtherCAT was to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs master uses the information from the ENI file to initialize and configure the EtherCAT network. The ESI files are provided by the vendor for each device. They contain information about the device functionality and its settings. The ESI files are used by the KAS IDEClosed"Integrated development environment" An integrated development environment is a type of computer software that assists computer programmers in developing software. IDEs normally consist of a source code editor, a compiler and/or interpreter, build-automation tools, and a debugger to generate the ENI file. The KAS controller’s EtherCAT master uses the ENI file for network initialization and configuration.

Figure 5-59: EtherCAT Network Architecture1

ENI File

A network configuration file in XMLClosed"Extensible Markup Language " XML is a general-purpose markup language. It is classified as an extensible language because it allows its users to define their own tags format, the ENI file describes the network topology, the initialization commands for each device, and commands which have to be sent cyclically. The ENI file is provided to the master, which sends commands according to this file.

The KAS IDE creates the ENI file after a network discovery, which can be exported or imported. A scan and compile should be redone, if the network changes, in order to regenerate the ENI file.

ESI File

A device description in XML format. This is a fixed file provided by the supplier of a given EtherCAT device. The ESI file contains information about the device's functionality and settings.

EtherCAT device vendors must provide an ESI file, which is used by the KAS IDE to compile the network information (e.g. process data structures, initialization commands) and create the ENI file.


  • KAS uses EtherCAT Network Information (ENI) schema version 1.3 (May 20, 2009). For more details, see the ETG.2100 specification at www.ethercat.org.