BCU 370 · Edition 01.19
34
Function
3 .4 .5 Network technology
All devices are connected in a bus structure (line). Up to
32 subscribers (masters or slaves) can be connected in
a single segment. The beginning and end of each seg-
ment is fitted with an active bus terminator. Both bus
terminators must have a permanent power supply to
ensure error-free operation. The power supply for the
bus terminator is provided by the BCU. The bus termi-
nator can be connected in the bus connection plug.
If more than 32 subscribers are implemented or if there
is a need to expand the network area, repeaters (ampli-
fiers) must be used to link the individual bus segments.
3 .4 .6 Configuration
When planning a PROFIBUS DP system, unit-specific pa-
rameters of each subscriber are to be taken into account.
To allow for simple and standardized planning, the param-
eters of the BCU..B1 have been summarized in a so-called
device master data file (GSD). The file structure is standard-
ized so that it can be read by the planning devices of differ-
ent manufacturers.
The GSD file can be downloaded from www.docuthek.
com, once you have registered. The steps required to copy
the file are described in the instructions for the automa-
tion system.
3 .4 .7 Bus communication
Input bytes (BCU
➔
master)
Bit
Byte 0
Byte 1
Byte 2
Byte 3
0
Burner operation
Reserved
Se
e t
ab
le o
n p
ag
e
P)
0 – 2
5.
5
µ
A o
f t
he b
ur
ne
r
25
5 s
te
ps
1
2
Fault lock-out
3
Controlled air flow
4
Open position
reached*
5
Closed position
reached*
6
ON
7
Manual mode
* Only on BCU 370..B1-3, three-point step control via PROFIBUS DP
Output bytes (master
➔
BCU)
Bit
Byte 0
0
Reset
1
Start-up
2
Controlled air flow
3
4
5
6
Open*
7
Close*
* Only on BCU 370..B1-3, three-point step control via PROFIBUS DP
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