Lenze I/O system 1000 System Manual - Manual (Page 733)

Appendix
Serial process interfacing
Principle of backplane bus communication
15
l
733 EDSIO1000 EN 7.0
Transmission with fragmentation:
In the case of the fragmented transmission, the number of user data and already part of
the user data are transmitted with the 1. telegram (header). Then the fragment telegrams
follow.
Procedure: Write 1. telegram
®write fragment ®write last fragment
Calculation of the number of fragments: number of fragments = (length + 3) / (IO_Size −
1)
Write 1. telegram (header)
Higher−level system EPM−S640/EPM−S650 Description
Byte Function Byte Function
0 Control byte Bits 3...0:
8
h
= idle state, no data available.
9
h
= start transmission with
fragmentation.
A
h
= transmission of last fragment.
B
h
= carry out a reset on the EPM−S640.
Bits 7...4:
Reserved for reception.
1 Telegram
information byte During the transmission process 00
h
(fixed).
2 High byte length User data length in bytes.
3 Low byte length
4 ... n−1 User data bytes
0 ... n−5 User data; n = number of the bytes
assigned in the address range (IO size)
®
¬
0 Acknowledgement
/ status Bits 3...0:
Reserved for reception.
Bits 7...4:
8
h
: acknowledgement, idle state
9
h
: fragmented transmission started.
A
h
: acknowledgement, data without
fragmentation received.
C
h
: status, reset was carried out on
EPM−S6x0.
D
h
: status, the length specified is invalid.
E
h
: status, EPM−S6x0 communication
error, partner is not responding.