Honeywell BCU 465 - Page 54

BCU 460, BCU 465 · Edition 11.19 54
Fieldbus communication
Inputs/Outputs
The digital input and output signals from the burner
control unit BCU are included in this module.
Input bytes (BCU ➔ PLC)
The input bytes describe the digital signals which are
transferred from the BCU to the digital inputs of the
PLC. The digital signals take up 3bytes (24bits).
Bit Byte n Byte n+1 Byte n+2 Format
0
Burner 1 operating
signal
Free
Flameless
operation
BOOL
1
Burner 2 operating
signal
Free Free BOOL
2 BCU system fault Air ON Free BOOL
3 Fault lock-out Pre-purge ON Free BOOL
4 Safety shut-down HT ON Free BOOL
5 Warning
Ready for
operation
Free BOOL
6 ON
Burner 1 flame
signal
Free BOOL
7 Manual mode
Burner 2 flame
signal
Free BOOL
Output bytes (PLC ➔ BCU)
The output bytes describe the digital signals which
are output by the PLC to the BCU. The digital signals
to control the burner control unit BCU occupy 2bytes
(16bits).
Terminals 1 to41 (dependent on parameters I061 to
I074) can be wired parallel to the bus communication.
This allows the BCU to be controlled using the digital
signals of the bus communication or the inputs at the
terminals.
Bit Byte n Byte n+1 Format
0 Reset
1)
Auxiliary gas BOOL
1 Burner 1 start
1)
Optional output BOOL
2 External air ON
1)
Cooling air valve BOOL
3 Pre-purge ON Free BOOL
4 Burner 2 start
1)
Free BOOL
5 Flameless mode ON
2)
Free BOOL
6 Free Free BOOL
7 Free Free BOOL
1) Terminals 1 to41 (dependent on parameters I061 to I074) can
be wired parallel to the bus communication.
2) Only with BCU465 depending on the parameter settings.
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