Siemens LMV51 Series Basic Documentation page 271

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HVAC Products
19.4.7 Increasing the manipulated variable in the case of a load change
(offset)
When changing the load under unfavorable setting conditions, it could happen that the
actual O2 value will drop below the O2-min-limit. To prevent this, the user can param-
eterize an increase of the O2 value in the event of load changes.
The parameter will define the increase of the O2 value in %. The increase is made in
relation to the setpoint.
Example:
O2 offset oil = 0.5 %, setpoint 1.4 %
reached will be 1.9 %.
When firing on oil:
Parameter:
O2 OffsetOil
When firing on gas:
Parameter:
O2 OffsetGas
The increase is made via the controller's manipulated variable. The current O2 value is
considered when calculating the increase.
Actual O2 value
O2 setpoint
There is only 1 increase of the O2 value per load change. The next increase will only
be possible on completion of the locking time for the load change.
There will be no increase of the O2 value when O2 trim control is deactivated.
Basic Documentation LMV5...
19 Addendum 4: LMV52... with O2 trim control and O2 module
In the event of a load change, the O2 value
Actual O2 value
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CC1P7550en
13.08.2004