Siemens LMV51 Series Basic Documentation page 269

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19.4.2 Load limitation with O
O trim control can be deactivated below an adjustable load limit. This can be selected
2
separately for gas- and oil-firing.
Parameter:
O CtrlThreshold
2
If the load drops below this limit, O
erates along the parameterized ratio curves. If the load increases and exceeds the O
trim control threshold by 5 percentage points, the O
19.4.3 Startup
With the parameter setting
Parameter:
O
2Ctrl
startup will be prevented until the O2 sensor has reached its operating temperature.
With the parameter setting
Parameter:
O Ctrl/Guard (conAutoDeac)
2
starts the burner directly, O
perature has been reached and sensor test has been successful.
Also refer to section 19.4.4 Heating up the O2 sensor after «PowerOn».
19.4.4 Heating up the O
When the system or the O2 module is switched on for the first time, the cold O2 sensor
is slowly heated up until its operating temperature is reached. When that temperature
is reached, the sensor needs another 10 minutes to attain its maximum temperature.
With the parameter setting
Parameter:
O Ctrl/Guard (O
2
start prevention will take place until the O2 sensor has fully assumed its operating tem-
perature, followed by burner startup. O
tivated the moment the controller locking time has elapsed.
With parameter setting
Parameter: O Ctrl/Guard (conAutoDeac)
2
the burner will immediately be started up. O
only take place when the sensor has fully assumed its operating temperature and after
the sensor test has been successfully completed.
19.4.5 Initialization of O2 trim controller
The system is put into operation with the O
Locking time startup commences when entering the operating phase. This locking
time is 10* Tau low-fire . On completion of this locking time startup , the dynamic re-
lease criterion of operation applies (refer to section 19.4.6 Behavior in the event of load
changes). When the above mentioned release criteria are satisfied, the O
ler will be initialized. To reach the O
nipulated variable will be calculated from the currently acquired O
value determined when making the setting, the O
That manipulated variable will then be increased by 3.7 % so that the resulting O
value will be somewhat higher than the O
sulting O value will be about 0.7 % higher than the O
2
setpoint will be ensured by the O
Basic Documentation LMV5...
19 Addendum 4: LMV52... with O2 trim control and O2 module
trim control
2
trim control will be deactivated and the system op-
2
/Guard (O / O
2-guard 2-control
trim control will be activated only when the operating tem-
2
sensor after «PowerOn»
2
/ O
2-guard 2-c
trim control in the operating position will be ac-
2
trim control in the operating position will
2
trim controller locked (safe ratio curve).
2
setpoint quicker, the theoretically required ma-
2
2
setpoint. With an increase of 3.7 %, the re-
2
trim controller.
2
trim controller will be reinitialized.
2
)
ontrol)
2
value, the O
2
setpoint and the standardized value.
setpoint. Fine-tuning to the O
2
2
trim control-
ratio
2
2
2
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CC1P7550en
13.08.2004