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Building Technologies
Basic Documentation LMV5...
CC1P7550en
19 O2 trim control with LMV52 and PLL52
22.05.2018
19.4.10 Control interventions
(switching functions)
by the O2 trim
controller
In order to prevent the burner from receiving insufficient amounts of air when the load
changes, the O
2
trim controller contains additional functions which can be used when
the
startmode
parameter is set to
standard
.
These become active if the O2 trim controller or precontrol is not optimally adjusted, or
if the burner’s behavior cannot be adequately mapped by the measured values.
The control interventions are also active during the controller locking time (waiting for 2
x
Tau current load
).
If the O
2
value drops below the setpoint in the direction of the O
2
minimum value, the
manipulated variable will be increased
⇑
more air supplied.
19.4.11
O
2
trim control behavior
O2 trim control behavior can be altered using the
O2TrimBehavior
parameter:
ForcdAirAdd
Air is added faster than it is reduced.
This setting is recommended for burners where the O2 setpoint is
close to the O2 minimum value.
Corresponds to the factory setting and the behavior of previous LMV5
software versions without this parameter.
ForcdAirRed
Air is reduced faster than it is added.
This setting is recommended for burners where the O2 setpoint is
close to the O2 maximum value.
symmetric
The time taken to add or reduce air is the same for both processes.
This setting is recommended if the user does not require trim control
behavior to be faster for one process over the other, if the difference
between the O2 minimum and O2 maximum values is very small, or if
the O2 setpoint is approximately in the middle of these two values
(burner head with metal mesh).
Parameter
Gas:
O2TrimBehavior (ForcdAirAdd, ForcdAirRed, symmetric)
Oil:
O2TrimBehavior (ForcdAirAdd, ForcdAirRed, symmetric)
