ESC Access

An EEPROM is an Electrically Erasable Programmable Read Only Memory. ESI stands for "EtherCAT Slave Information". The "EtherCAT Slave Information" is stored in the ESI EEPROM. The ESI EEPROM is located in the EtherCAT Slave Controller (ESC). It is a non-volatile memory used to store the ESC configuration and the device description.

The ESI EEPROM uses word addressing. The EtherCAT slave controller configuration area is located in the memory area from word 0 to word 7. There the EEPROM contains configuration data for the EtherCAT Slave Controller (ESC). The configuration data is followed by the vendor ID, the product code, the revision number and the serial number.

The ESC configuration area is automatically read by the ESC on power-on or during a reset. It contains the PDI configuration, DC settings and the Configured Station Alias. PDI stands for "Process Data Interface" or "Physical Device Interface", an interface that allows access to the ESC from the process side. DC settings are Distributed Clocks settings that affect the mechanism that synchronizes the EtherCAT devices with each other. The Configured Station Alias is used to address the network node. A checksum is used to check whether the ESC configuration data is consistent.

The EtherCAT master can initiate a reloading of the EEPROM contents. In this case, the Configured Station Alias and the PDI control bit are not accepted. They are only accepted during the initial EEPROM loading after power-on or a reset.