Beckhoff EL9 Series Documentation page 69

Data management and function "NoCoeStorage"
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. "CoE Online " tab) 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.
Data management
If slave CoE parameters are modified online, Beckhoff devices store any changes in a fail-safe
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 val-
ues, depends on the firmware version.
Please refer to the technical data in this documentation as to whether this applies to the respective
device.
• 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.
• Function is not supported: continuous changing of CoE values is not permissible in view of the
lifetime limit.
Startup list
Changes in the local CoE list of the terminal are lost if the terminal is replaced. If a terminal is re-
placed with a new Beckhoff terminal, it will have the default settings. It is therefore advisable to link
all changes in the CoE list of an EtherCAT slave with the Startup list of the slave, which is pro-
cessed whenever the EtherCAT fieldbus is started. In this way a replacement EtherCAT slave can
automatically be parameterized 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 Version: 3.9
Basics communication
69