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FnIO EtherCAT Network Adaptor NA-9286
FnIO S-Series
Copyright(C) CREVIS Co.,Ltd Support +82-31-899-4599 URL : www.crevis.co.kr
6. ETHERCAT BASICS
6.1.
EtherCAT Protocol
The EtherCAT protocol uses an officially assigned EtherType inside the Ethernet Frame. The use of this EtherType
allows transport of control data directly within the Ethernet frame without redefining the standard Ethernet frame. The
frame may consist of several sub-telegrams, each serving a particular memory area of the logical process images that can
be up to 4 gigabytes in size. Addressing of the Ethernet terminals can be in any order because the data sequence is
independent of the physical order. Broadcast, Multicast and communication between slaves are possible.
6.2.
EtherCAT State Machine
The state of the EtherCAT slave is controlled via the EtherCAT State Machine (ESM). Depending upon the state,
different functions are accessible or executable in the EtherCAT slave. Specific commands must be sent by the
EtherCAT master to the device in each state, particularly during the bootup of the slave.
A distinction is made between the following states:
Init
Pre-Operational
Safe-Operational and
Operational
Boot
The regular state of each EtherCAT slave after bootup is the OP state.
