Host system
CP
Byte
Function
Byte
Function
t
0
Info-Byte
1
Telegram-Info-Byte
2
Length high byte
3
Length low byte
[4]
Offset high byte
[5]
Offset low byte
6...n-1
User data
with n = number of used bytes in the address area (IO-Size)
After the data are processed in the host system, you have to send an acknowledge to the
CP, by copying bit 3...0 of byte 0 of the input area to bit 7...4 of byte 0 of the output area.
Only then the CP can send further data.
0
Acknowledgement
u
0
Bit 3...0
8h: Idle state - no data available
9h: Data were transferred with fragmentation
Ah: Data were transferred without fragmentation
Bit 7...4
Reserved for sending
00h:
The telegram does not contain any additional offset information.
04h:
The telegram contains additional offset data, which are located as word
after
Length
. With this offset the position of the user data in the input
area is defined.
Length of user data in byte plus 2 bytes for RetVal.
Principle of communica-
tion with fragmentation
Calculating the number of
fragments
Info-Byte
Telegram-Info-Byte
Length
VIPA System SLIO
Deployment
Principal communication via back plane bus > Receiving data
HB300 | CP | 040-1CA00 | en | 18-28
48