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Building Technologies
Basic Documentation LMV5...
CC1P7550en
19 O2 trim control with LMV52 and PLL52
22.05.2018
19.5.2 Switch-off criteria of the O2 alarm
19.5.2.1 O2 minimum value alarm
If …
a) the O2 actual value falls below the O2 minimum value delayed via the PT1 element
for the period
Time O2 Alarm
or
b) the actual O2 value falls below the smallest parameterized O2 minimum value for
the period
Time O2 Alarm
, one of the following reactions takes place, depending
on the operating mode:
∂
In all O2 trim controller operating modes
except
conAutoDeac
:
Safety shutdown is initiated, followed by repetitions if possible, otherwise lockout.
∂
In the
conAutoDeac
: O2 trim controller operating mode:
If an error occurs in connection with O2 measurement, the PLL52, the QGO20, or
the sensor test, the LMV5 automatically switches the
O2 Control
operating mode to
auto deact
.
If the O2 minimum value alarm responds, the system returns to the ratio control
curves.
After a period of 3 x
Tau
time constants, a check is carried out to see whether the
O2 value is above the O2 minimum value:
- If the O2 value exceeds the O2 minimum value, the controller is released again.
- If the O2 value is still below the O2 minimum value, safety shutdown is initiated,
followed by repetition. The O2 value may fall below the minimum value the number
of times entered in parameter
NumMinUntilDeact
until the O2 trim controller is
deactivated automatically.
Parameter
Gas:
Time O2 Alarm
Oil:
Time O2 Alarm
The following parameter is only active in the
conAutoDeac
O2 trim controller operating
mode.
Parameter
Gas:
NumMinUntilDeact
Oil:
NumMinUntilDeact
