Lenze I/O system 1000 System Manual - Manual (Page 732)

Appendix
Serial process interfacing
Principle of backplane bus communication
15
l
732 EDSIO1000 EN 7.0
15.1.3 Principle of backplane bus communication
Transmit data
During transmission, the higher−level system enters the data to be output in the output
area and transfers them to the I/O compound module together with the control byte. At
every telegram, the I/O compound module responds with an acknowledgement by
copying bits 3 ... 0 of byte 0 of the output area to bits 7 ... 4 of byte 0 of the input area, or
by returning a corresponding status message via this byte. Depending on the length of the
data to be transmitted, the telegram is to be transferred to the I/O compound module in
one or several fragments. In the case of the fragmented transmission, each fragment is
acknowledged by the I/O compound module.
Transmission without fragmentation:
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.
A
h
= start transmission without
fragmentation.
B
h
= carry out a reset on the EPM−S6x0.
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
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.
Example of transmission without fragmentation: IO size = 60 bytes, length = 40 bytes
Higher−level system EPM−S640/EPM−S650 Description
Byte Value Byte Value
0 0A
h
Command: start transmission without
fragmentation.
1 00
h
Telegram information
2 00
h
User data length high byte
3 28
h
User data length low byte
4 ... 43 x User data byte 0 ... 39
44 ... 59 − Not used
®
¬
0 A0
h
Acknowledgement