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Siemens Building Technologies
Basic Documentation LMV5...
CC1P7550en
HVAC Products
19 Addendum 4: LMV52... with O2 trim control and O2 module
13.08.2004
19.11.5 Setting O2 trim control
Since with O
2
trim control activated, the O
2
monitor is always active also, the O
2
moni-
tor should already be set. For the initial setting, O
2
trim control should remain deacti-
vated, and the O
2
monitor can be activated. Prior to setting the O
2
trim controller, both
ratio control and the loads of the curvepoints should be correctly set. This facilitates
correct functioning of precontrol.
Also refer to subsection 19.11.1
Setting ratio control
.
If the ratio curves are changed later, O
2
trim control must also be read-
justed.
It is important to make all settings of the O
2
trim controller when environmental condi-
tions do not change. For this reason, when making corrections later, all points must be
set again. When setting O
2
trim control, the user is guided through the necessary set-
ting steps.
First, select the desired curvepoint and confirm with
Enter
(point 1 cannot be set since
O
2
trim control does not approach any load below point 2). The system approaches the
selected point on the ratio curve.
P
o
i
n
t
:
2
O 2 - R a t i o C o n : x x x x
O 2 S e t p o i n t : x x x x
S t a n d V a l : x x x x
The display will change. During this step, the system acquires the O
2
value on the ratio
curve. The actual O
2
value is displayed and the operator is prompted to confirm when a
stable O
2
value has been reached. This is important since the value is used for calcu-
lating precontrol. In the future, the PC tool will be useful for making checks.
P
o
i
n
t
:
2
O 2 - R a t i o C o n : 5 . 4
I f V a l u e
S t a b l e
C o n t i n u e W
E n t e r
Then, the measured O
2
ratio value will be displayed. The cursor now indicates the
standardized value. By changing this value, the relative amount of air will be reduced,
whereby the standardized value corresponds to the relative air rate reduction. The
standardized value is only changed until the actual O
2
value reaches the required O
2
setpoint, which is then displayed. The setting may only be confirmed after a constant
O
2
value has been attained. The PC tool will be useful for making checks.
P
o
i
n
t
:
2
O 2 - R a t i o C o n : 5 . 2
O 2 - S e t p o i n t : 2 . 0
S t a n d V a l : 1 5 . 3
Now, the operator must decide whether he wants to adopt or reject the settings.