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Building Technologies
Basic Documentation LMV5...
CC1P7550en
19 O2 trim control with LMV52 and PLL52
22.05.2018
19.4.7 Modulation release on startup
Parameter setting
standard
Modulation by the load controller is always enabled when the system is put into
operation.
Parameter settings
Ign Load TC, IgnPtWithTC
or
IgnPtWoutTC
With these options, the burner is put into operation straight away with the O2 trim
controller initialized.
As various factors mean that initialization is not infinitely accurate, modulation of the
load controller is locked until the O2 trim controller has corrected the deviation, in other
words until the O2 setpoint has reached a band of ±0.2%.
Following this, modulation of the load controller is enabled.
19.4.8 Behavior in the event of load changes
(dynamic release
criterion)
Slow load changes
↑
O2 trim control remains active
Fast
load changes
↑
O2 trim control becomes temporarily inactive
↑
Precontrol remains active
↑
O2ModOffset
value becomes active for O2 precontrol (also refer to chapter
Increasing the manipulated variable in the case of
fast
load changes
)
A load change is considered to be
fast
if an internally calculated value exceeds the
LoadCtrlSuspend
threshold that can be parameterized.
Example:
- 0%
↑
Each load change is considered to be
fast,
resulting in the temporary inactivation
of O2 trim control
- 25%
↑
Only large and fast load changes are considered to be
fast,
resulting in the
temporary inactivation of O2 control
O2 trim control is reactivated when the internally calculated value exceeds the
LoadCtrlSuspend
threshold and a subsequent waiting time of
2 x Tau current load
has elapsed.
Parameter
Gas:
LoadCtrlSuspend
Oil:
LoadCtrlSuspend
