Switch-Off Criteria Of The O2 Alarm; O2 Minimum Value Alarm - Siemens LMV50 Series Manual

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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
Basic Documentation LMV5...
19 O2 trim control with LMV52 and PLL52
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CC1P7550en
22.05.2018