The content of these data depends on the structure of data in the send buffer. For more
information, see the following pages.
4.3 Principal communication via back plane bus
4.3.1 Sending data
When sending from the host, the output data are entered in the output area and by
means of the
Control-Byte
transferred to the CP.
The CP responds every telegram with an acknowledgement, by copying bit 3...0 of byte 0
of the output area to bit 7...4 of byte 0 of the input area or sending back a
status message
via this byte.
Depending on the length of data the telegram is to be transferred to the CP as one frag-
ment or with multiple fragments. With the fragmented transmission, each fragment is
acknowledged by the CP.
Host system
CP
Byte
Function
Byte
Function
0
Control-Byte
u
1
Telegram-Info-Byte
2
Length High-Byte
3
Length Low-Byte
4...n-1
User data Byte 0...n-5
t
0
Acknowledgement / Status
with n = number of used bytes in the address area (IO-Size)
Bit 3...0
n
8h: Idle state - no data available
n
Ah: Start transfer without fragmentation
n
Bh: Execute a reset on the CP
Bit 7...4
Reserved for receipt
00h (fix) when data are sent.
Length of user data for serial communication in byte.
Enter here the user data for the serial communication.
CP_OUT_x
Principle of the communi-
cation without fragmenta-
tion
Control-Byte
Telegram-Info-Byte
Length
User data
VIPA System SLIO
Deployment
Principal communication via back plane bus > Sending data
HB300 | CP | 040-1CA00 | en | 18-28
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