Instruction Manual

EDS84DMOTECAT EN 2.1 - 11/2012 L 33
Communication manual 8400 motec EtherCAT®
Data transfer
EtherCAT frame structure
7.1 EtherCAT frame structure
EtherCAT frames have the following structure:
Ethernet header
The Ethernet header contains the following information:
 Target address of the EtherCAT frame (destination)
 Source address of the EtherCAT frame (source)
 Type of the EtherCAT frame (EtherType = 0x88A4)
Ethernet data
The Ethernet data contain the following information:
 Length of the datagrams within the EtherCAT frame (Length)
 One reserved bit (Reserved)
 Type of the datagrams within the EtherCAT frame (Type)
 EtherCAT datagrams (Datagrams)
FCS
Checksum of the EtherCAT frame
Ethernet header Ethernet data FCS
48 bits 48 bits 16 bits 11 bits 1 bit 4 bits 48 ... 1498 bytes 32 bits
Destination Source EtherType Frame header Datagrams
Length Reserved Type