Lenze EtherCAT control technology - Manual (Page 20)

Control technology | EtherCAT communication manual
The Lenze control system with EtherCAT
Brief description of EtherCAT
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DMS 3.1 EN 01/2011 TD17
4.1.3.2 Addressing of the slaves
The EtherCAT system uses two types of addressing for the slaves:
 Auto-increment addressing
 Fixed-address addressing
The auto-increment addressing is used by the master during the initialisation phase of the
fieldbus. When the Pre-Operational state has been reached, the master uses the Fixed-
Address addressing.
Auto-increment addressing
The auto-increment addressing is based on the bus topology. Each slave can be addressed
by means of its physical position within the fieldbus.
 Slave 1 = address 0
 Slave 2 = address -1
 Slave 3 = address -2 etc.
The master transmits a telegram to the slave address. Each slave increments the address
during the telegram cycle. A slave to which a telegram is addressed recognises the
telegram by means of the address 0.
A configuration example is given under:
 Determining the physical EtherCAT configuration (fieldbus scan)
( 47)
Fixed-address addressing
With the fixed-address addressing, the slaves are addressed via the station address
distributed by the master in the start-up phase.
In the EtherCAT bus topology in the »PLC Designer«, the first slave gets the address 1001,
the second slave the address 1002, etc. The EtherCAT addresses cannot be changed.
The EtherCAT address of the master is 0. Master objects with this address can also be
accessed via CoE.
Example
The first slave of a configuration obtains the following addresses:
 0 by the auto-increment mode
 1001 by the fixed addressing mode (default address of the first slave in the »EtherCAT
Configurator«).