Transmission Channel; Table 26: Structure Of The Simple Header; Table 27: Structure Of The Extended Header - WAGO -I/O-SYSTEM 750 Manual

WAGO-I/O-SYSTEM 750
750-658 CAN Gateway
Structure of the simple header:

Table 26: Structure of the Simple Header

Bit 7 Bit 6
0
Structure of the extended header:

Table 27: Structure of the Extended Header

Bit 7 Bit 6
1
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.
10.1.2

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
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.
Manual
Version 1.2.0, valid from FW/HW-Version 01/01
Simple header
Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Length
Extended header
Bit 5 ... 0
0 Length High
Part of the message
Bit 7 ... 0
Length Low
Appendix
Data element length max. 127 bytes
0: Simple header
Bit 7 ... 0
Protocol ID
Protocoll_ID 0..255
Data element length
max. 16383 bytes
10: Extended header
73