BCU 480 · Edition 03.16l 39
Parameters
4.4.2 Minimum burner pause time t
BP
Parameter 21
Programmable time between 0 and 250 s
t
SA2
88 08 06 07 08
t
t
BP
t
FS2
4
5
1
7
9
18-19
12
V1
14 V2
16-17
05 04
1
28-29
2
21
1
9
2
ϑ
1
ϑ
2
26
An immediate restart of the burner after a controlled
shut-down, a start-up attempt, restart, cooling or purg-
ing is prevented by the pause time. The pause time
starts when the air valve is switched off. If a start-up
signal (ϑ) is applied before expiry of this time, start-up
is delayed until the end of the pause time.
After the pause time, the burner is started if the start-
up signal (ϑ) is applied.
The minimum burner pause time t
BP
serves to adapt the
program sequence to the requirements of the applica-
tion.
The time should be set such that the system can be
moved to ignition position, i.e. butterfly valves can be
closed and, possibly, gas can be flared off, before a re-
start occurs.
Example of application
t
1
2
BCU 480
14
12
23
26
SPS
PLC
API
DI
L1, N, PE
P
22 4
21
18
19
16
17
28
29
24
2
1
A
P
5
3
DI
6
04 02–04 06–08 06–08
04
µC
ϑ
1
ϑ
2
ϑ
1
ϑ
2
VR..R
VAG
VBY
2
1
The pause time has an effect on the behaviour of the
main burner only. Reason: the pilot burner is only used
in single-stage operation.
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