EDS94AYCEN EN 9.0 - 09/2012 L 39
E94AYCEN communication manual (Ethernet)
Parameter data transfer
Structure of the Ethernet data telegram
7.1 Structure of the Ethernet data telegram
The GCI protocol is used for communication.
The Ethernet data telegram is shown below. Here, the GCI header represents the part of
the program that is independent of the type of command transmitted.
[7-2] Structure of the GCI header within the Ethernet frame
E94YCEN015
Ethernet
Header
IP Header
TCP/IP
Header
P0…P4
Ethernet
CRC
SIZEGTI
rspa
GMT
GSV
res
GCI Header
SIZE res res
GMQ
Field Size Description
GMT 1 Byte GCI message type
0x01 Reserved
GSV 1 Byte GCI service identification
0x82 Reading parameters
0x83 Writing parameters
GMQ 1 Byte GCI message qualifier
rsp Request/response (1 bit)
0: request
1: response
aAbort (1 bit)
0: data transmission ok
1: data transmission aborted
res Reserved (6 bits)
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 User data length (P0, P1, P2, P3, P4)
0x14 20 bytes
... ...
0x114 276 bytes
res 2 bytes Reserved
0x0000 Data contents = 0
Bit 7
rsp a
Bit 6 Bit 5 ... Bit 0
res
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