Beckhoff CU2508, Documentation

Page: 65 / 78

Appendix
Real-time Ethernet port multiplier 65 Version: 2.6
5 Appendix
5.1 ESL Protocol
The EtherCAT Switch Link protocol (ESL) from Beckhoff is a simple extension for the control of EtherCAT
infrastructure components. It is currently used (as of 2010) for the operation of the
ET2000 Industrial Ethernet
Multichannel Probe and the CU2508.
The ESL data consist of 16 bytes of control data and information, which are added as a prefix (in front) or as
a postfix (to the end) of an existing Ethernet data frame. The check sum (CRC) is adapted accordingly.
Fig. 86: CU2508 ESL prefix
The ESL data are structured as follows:
Fig. 87: ESL structure
Ethernet network monitors
The freely available network monitor Wireshark has contained an interpreter for the ESL protocol since the
version 1.4.2.
5.2 Firmware Update
The CU2508 has 2 different firmware versions, one for the FPGA and one for the controller.
The CU2508 must be operated in a special configuration for the determination of the current firmware
version and for updating. It must therefore be removed from the application and is to be operated as an
individual EtherCAT device on a TwinCAT system.
The following steps must be carried out in order to update:
1. TwinCAT
On the PC system used for programming, TwinCAT must have at least version 2.11R2 build 2021 or
TwinCAT 3.1.