BECKHOFF EL9xxx - Manual (Page 57)

Basics communication
The figure above shows the CoE objects available in device "EL2502", ranging from x1000 to x1600. The
subindices for x1018 are expanded.
Data management
Some parameters, particularly the setting parameters of the slave, are configurable and writeable. This can
be done in write or read mode
• via the System Manager (Fig. 1) by clicking
This is useful for commissioning of the system/slaves. Click on the row of the index to be
parameterised and enter a value in the "SetValue" dialog.
• from the control system/PLC via ADS, e.g. through blocks from the TcEtherCAT.lib library
This is recommended for modifications while the system is running or if no System Manager or
operating staff are available.
If slave CoE parameters are modified online, Beckhoff devices store any changes in a fail­safe manner in the
EEPROM, i.e. the modified CoE parameters are still available after a restart. The situation may be different
with other manufacturers.
An EEPROM is subject to a limited lifetime with respect to write operations. From typically 100,000 write
operations onwards it can no longer be guaranteed that new (changed) data are reliably saved or are still
readable. This is irrelevant for normal commissioning. However, if CoE parameters are continuously changed
via ADS at machine runtime, it is quite possible for the lifetime limit to be reached. Support for the
NoCoeStorage function, which suppresses the saving of changed CoE values, depends on the firmware
version.
Note
Data management
ü Data management function
a) If the function is supported: the function is activated by entering the code word
0x12345678 once in CoE 0xF008 and remains active as long as the code word is not
changed. After switching the device on it is then inactive. Changed CoE values are not
saved in the EEPROM and can thus be changed any number of times.
b) Function is not supported: continuous changing of CoE values is not permissible in view
of the lifetime limit.
Note
Startup list
Changes in the local CoE list of the terminal are lost if the terminal is replaced. If a terminal
is replaced with a new Beckhoff terminal, it will have the default settings. It is therefore ad­
visable to link all changes in the CoE list of an EtherCAT slave with the Startup list of the
slave, which is processed whenever the EtherCAT fieldbus is started. In this way a replace­
ment EtherCAT slave can automatically be parameterised with the specifications of the
user.
If EtherCAT slaves are used which are unable to store local CoE values permanently, the
Startup list must be used.
Recommended approach for manual modification of CoE parameters
• Make the required change in the System Manager
The values are stored locally in the EtherCAT slave
• If the value is to be stored permanently, enter it in the Startup list.
The order of the Startup entries is usually irrelevant.
EL9xxx 57 Version 3.1