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Building Technologies
Basic Documentation LMV5...
CC1P7550en
19 O2 trim control with LMV52 and PLL52
22.05.2018
19.11.5 Setting O2 trim control
Since with O2 trim control activated, the O2 alarm is always active too, the O
2
alarm
should already be set. For the initial setting, O2 trim control should remain deactivated,
and the O2 alarm can be activated. Prior to setting the O2 trim controller, both fuel-air
ratio control and the loads of the curvepoints should be correctly set. This facilitates
correct functioning of precontrol. Also refer to chapter
Setting fuel-air ratio control.
Β
Note!
If the ratio control curves are changed later, O2 trim control must also be readjusted.
It is important to make all settings of the O2 trim controller when environmental
conditions do not change. For this reason, when making corrections later, all points
must be set again. When setting O2 trim control, you are guided through the necessary
setting steps.
For adaption of the O2 trim controller during low-fire operation, the following parameter
is available:
Parameter LowfireAdaptPtNo
This parameter is intended for plant where the flue gas speed at curvepoint 2 is too low
to produce valid adaption values.
Β
Note!
O2 trim control is not performed below the parameterized
LowfireAdaptPtNo
.
First, select the required curvepoint and confirm by pressing
Enter
(curvepoints under
LowfireAdaptPtNo
cannot be set, since loads below
LowfireAdaptPtNo
cannot be
approached with O2 trim control). The system approaches the selected point on the
ratio control curve.
P
o
i
n
t
:
2
§
O
2
R
a
t
i
o
C
o
n
:
#
#
#
#
O
2
S
e
t
p
o
i
n
t
:
#
#
#
#
S
t
a
n
d
a
r
d
V
a
l
:
#
#
#
#
The display changes. During this step, the system acquires the O2 value on the ratio
control curve. The actual O2 value is displayed and the operator is prompted to confirm
when a stable O2 value is reached. This is important since the value is used for
calculating precontrol. In the future, the PC software will be useful for making checks.
P
o
i
n
t
:
2
§
O
2
R
a
t
i
o
C
o
n
:
5
.
4
W
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V
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