1 structure of the ethercat data telegram, Structure of the ethercat data telegram, 3communication with the controller – Lenze i700 User Manual

Page 34

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3

Communication with the controller

3.6

Ethernet over EtherCAT (EoE)

34

Lenze · i700 servo inverter · Reference manual · DMS 1.5 EN · 03/2014 · TD05

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3.6.4.1

Structure of the EtherCAT data telegram

The GCI protocol is used for communication.
The EtherCAT data telegram is shown below. Here, the GCI header represents the part of the

program that is independent of the type of command transmitted.

[3-2]

Structure of the GCI header within the EtherCAT frame

EtherCAT

Header

IP Header

TCP/IP
Header

GCI Header

P0 ... P4

EtherCAT

Footer

GMQ

GMT

GSV

GTI

SIZE

SIZE

res

res

Field

Size

Description

GMT

1 byte

GCI message type

0x01 Reserved

GSV

1 byte

GCI service identification

0x82

Read parameters

0x83

Write parameters

GMQ

1 byte

GCI message qualifier

Bit 7

rsp (Request/Response)

0

Request

1

Response

Bit 6

a (Abort)

0

Data transfer OK

1

Abort of the data transfer

• The transfer is either aborted by the client or the server of a

parameter data telegram.

• A message is aborted without any confirmation. If the client waits

for its message to be confirmed, it will receive the abort notice

instead.

Bit 5 ... bit 0

res (reserved)

0b000000

Data contents = 0

GTI

1 byte

GCI transaction ID

0x00 Serial number (transaction identification)

• For each client a definite serial number (0 ... 255) is allocated.

• The serial number in the multitasking environment is used for

referencing to the calling tasks (reverse transaction).

...

0xFF

SIZE

2 bytes

Length of the user data

• The user data area or the data telegram contains the parameter data.

Assignment of user data areas P0 ... P4

0x14 20 bytes

... ...

0x114 276 bytes

res

2 bytes

Reserved

0x0000 Data contents = 0

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