EtherCAT Slave 入门教程 - SDO服务（1）

邮箱服务数据帧

帧结构

• EtherCAT子报文:

子报文头	数据	WKC

数据：

邮箱协议数据

邮箱协议数据:

Mailbox Header	Mailbox Data

Mailbox Data:

CoE Header	SDO

SDO:

SDO Header	SDO Data

• 描述

1. Mailbox Header: 6 octets
   1. Length：2 octets, 指定Mailbox Data的字节数
   2. Address: 2 octets, 主从通信时，为从站地址；从站间通信，为目的从站地址

   3. Flags: 2 octets

      field	size	detail
      channel	6 bits	0(reserved)
      priority	2 bits	0: lowest ... 3: highest
      type	4 bits	mailbox data type
      counter	3 bits	counter of mailbox services 1~7
      reserved	1 bits	0

2. Mailbox Data: x~1480 octets
   1. CoE Header: 2 octets
   2. SDO: 8~1478 octets
      1. SDO Header: 4 octets
      2. SDO Data: 4~1474 octets

SDO服务

1. Mailbox Data type:

   value	type	detail
   1	AoE	ADS over EtherCAT
   2	EoE	Ethernet over EtherCAT
   3	CoE	CANopen over EtherCAT
   4	FoE	File Access over EtherCAT
   5	SoE	Servo Drive Profile over EtherCAT
   15	VoE	Vendor specific protocol over EtherCAT

2. CoE Header:

   field	size	detail
   number	9 bits	0
   reserved	3 bits	0
   service	4 bits	1: Emergency 2: SDO请求 3: SDO响应 4: TxPDO 5: RxPDO 6: TxPDO远程请求 7: RxPDO远程请求 8: SDO信息