WAGO-I/O-SYSTEM 750
Appendix 85
750-658 CAN Gateway
Manual
Version 1.2.1, valid from FW/HW-Version 01/01
Structure of the simple header:
Table 32: Structure of the Simple Header
Simple header
Bit 7 Bit 6
Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0
Length
Structure of the extended header:
Table 33: Structure of the Extended Header
Extended header
Bit 7 Bit 6
Bit 5 … 0
Bit 7 … 0
Bit 7 … 0
1
0
Length High
Length Low
Protocol ID
A message that uses this header can contain 16383 bytes of user data. In
addition, the message can have a protocol ID. This protocol ID allows the
message to include a logical meaning.
12.1.2 Transmission Channel
To transfer a message over a narrow channel, synchronization between sender
and receiver is required. Therefore, the transmission channel is divided into a
synchronization part and a data part.
For synchronization, a so-called handshake byte (HB) is defined.
The handshake byte occupies the first byte of the transmission channel while part
of the message is always delivered in the remaining bytes.
HB
Part of the message
There is always one transmission channel from the sender to the receiver and
one transmission channel from the receiver to the sender. Both channels do not
have to be the same size. However, the minimum size is 1 byte.
Data element length max. 127
bytes
0: Simple header
Protocoll_ID 0..255
Data element length
max. 16383 bytes
10: Extended header
