BCU 580 · Edition 11.15l 43
Profinet
“Inputs/outputs” module –slot 1
The digital input and output signals from the burner
control units BCU 560, BCU 565 and BCU 580 are in-
cluded in this module.
Input bytes (device ➔ controller)
The input bytes describe the digital signals which are
transferred from the BCU (IO device) to the digital in-
puts of the PLC (IO controller). The digital signals take
up 2 bytes (16 bits).
Bit Byte n Byte n+1 Byte n+2 Format
0
Burner 1
operating signal
Max. capacity
reached1)
menox ON BOOL
1
Burner 2
operating signal
Min. capacity
reached
1)
Free BOOL
2 BCU system fault Air ON Free BOOL
3 Fault lock-out Pre-purge ON Free BOOL
4 Safety shut-down DI ON Free BOOL
5 Warning
Ready for
operation
Free BOOL
6 ON
Burner 2 flame
signal
Free BOOL
7 Manual mode
Burner 1 flame
signal
Free BOOL
1)
Only with three-point step control via bus.
Output byte (controller ➔ device)
The output byte describes the digital signals which are
output by the PLC (IO controller) to the BCU (IO device).
The digital signals to control the burner control unit
BCU occupy 1 byte (8 bits).
Parallel to the bus communication, terminals 1 to 4, 44
and 50 of the BCU can be wired. This allows the BCU to
be controlled using the digital signals of the bus com-
munication or the inputs at the terminals.
In the event that the bus communication is faulty or
interrupted and during the initialization of the bus com-
munication after switching on, the digital signals are
interpreted as “0”. If the BCU is controlled using the
inputs at the terminals during this time, the normal pro-
gram runs even if the bus communication is faulty or
interrupted.
Bit Byte n Format
0 Reset
1)
BOOL
1 Burner 1 start
1)
BOOL
2 External air ON
1)
BOOL
3 Pre-purge ON BOOL
4 Burner 2 start
1)
BOOL
5 menox ON BOOL
6 Open control element, three-point step Open
2)
BOOL
7 Close control element, three-point step Close
2)
BOOL
1)
Parallel to the bus communication, terminals 1 to 4 can be wired.
2)
Only with three-point step control via bus.
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