Siemens LMV50 Series Manual page 256

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Building Technologies
O2 trim control in operation is activated only when the operating
temperature is reached and the O2 sensor test has been successfully
completed. If the O2 maximum value alarm responds, or if an error
occurs in connection with O2 measurement, the O2 module, the O2
sensor, or the sensor test, OptgMode is automatically switched 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. The O2 minimum value
alarm remains active.
The system operates along the parameterized ratio control curves,
and this parameter is set to auto deact. The AZL5 indicates
automatic deactivation. The error code is maintained until O2 trim
control is manually deactivated or activated
auto deact O2 trim control was deactivated automatically by the LMV5. The
system operates along the parameterized ratio control curves. Do not
select this system parameter! To deactivate the O2 trim controller /
O2 alarm, the man deact parameter setting must be used. If an error
occurs in connection with O2 measurement, the O2 module, the O2
sensor, the sensor test, or the O2 maximum value alarm, there is no
response. If the O2 minimum value alarm responds and a valid O2
measured value is present, safety shutdown is initiated once the time
has elapsed (3 x Tau time constants + Time O2 Alarm).
Also refer to the chapter Heating up the QGO20 sensor after «Power On».
Parameter OptgMode (man deact / O2 Alarm / O2 Control / conAutoDeac / auto
deact)
Basic Documentation LMV5...
19 O2 trim control with LMV52 and PLL52
CC1P7550en
22.05.2018