BCU 580 · Edition 11.15l 26
Air control
4.1 Capacity control
4.1.1 BCU..F1/F2
V1
IC 20 + BVA
BCU 580..C0F1
µC
38371817
1 2 3
FCU 500
Process control (PCC)
46
49
50
P
HT
A
ϑ1
13
14
57
TZI/TGI
9
8
5
VAS
VAS 1
VAG
V2
V4
M
52 53 54 55 56
4
41
42
43
1
2
ϑ2
PLC
The BCU..F1/F2 activates a control element via the out-
puts for capacity control (terminals 53 to 56) for purg-
ing, cooling or starting the burner. This control element
moves to the required position for the relevant operat-
ing situation.
As soon as there is a purge signal at terminal 50 of
BCU..F1/F2, the control element is activated by the
outputs for capacity control to approach the position
for pre-purge. The protective system (e.g. FCU 500)
starts the pre-purge time if there is adequate air flow.
After the elapse of the pre-purge time, the control ele-
ment moves to the ignition position. Once the protec-
tive system (terminal 46, safety interlocks) has issued
the enable signal, the pilot and main burners can be
started by the start-up signals at terminals 1 and 4. The
control element can be activated to control the burner’s
capacity dependent on parameters 48 and 49.
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