Burner Start Mode For O2 Trim Control (Only Lmv52.4, Only In Operating Modes O2 Control And Conautodeac) - Siemens LMV50 Series Manual

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19.4.5 Burner start mode for O2 trim control (only LMV52.4, only
in operating modes O2 Control and conAutoDeac)
This startup behavior startup behavior was implemented specially for use with super-
low NOx burners (burner head with metal mesh), as these types of burners require the
burner to be started at the O2 setpoint.
The burner head with metal mesh can only be operated in a narrow O2 band.
The new start modes are used so that the O2 band can be reached on burner startup,
particularly in the event that the environmental conditions have changed significantly
compared to those of the burner setting.
As active O2 trim control is required in order to comply with the narrow O2 band, these
start modes are only active in the O2 Control and conAutoDeac operating modes for
the O2 trim controller.
If the start mode is parameterized to Ign Load TC, IgnPtWithTC or IgnPtWoutTC, the
air rate can also be increased in relation to the fuel rate; this means that the actuators
used for determining the amount of air can be driven to positions above the ratio control
curve.
Additionally, the fuel rate is altered if the required difference between the fuel and air
rate cannot be achieved by altering the air rate (e.g. at the highest curvepoint when air
rate > fuel rate).
standard The system is started using the parameterized ignition positions and
drives to the ratio control curves positions with the O2 trim
controller locked in phase 54 (or phase 50).
This corresponds to the factory setting and the behavior of previous
LMV5 software versions without this parameter.
Ign Load TC The system is not started using the parameterized ignition positions,
and instead goes directly to the O2 setpoint (with the O2 trim
controller initialized via temperature compensation).
The ignition load can be set using the Load of Ignition parameter.
The O2 trim controller is initialized using temperature compensation;
a supply air temperature sensor is required for this.
IgnPtWithTC The system is started using the parameterized ignition positions and
travels directly to the O2 setpoint in phase 54 or phase 50 (with the
O2 trim controller initialized via temperature compensation).
The O2 trim controller is initialized using temperature compensation;
a supply air temperature sensor is required for this.
IgnPtWoutTC The system is started using the parameterized ignition positions and,
with O2 trim controller initialized to 0, travels directly to the non-
temperature-compensated O2 setpoint in phase 54 (or phase 50).
The O2 trim controller initialization is made without temperature
compensation; a supply air temperature sensor is not required for
this.
Parameter Startmode (standard, Ign Load TC, IgnPtWithTC, IgnPtWoutTC)
Note!
In order to be able to use Ign Load TC, IgnPtWithTC or IgnPtWoutTC, the burner must
initially be started using the standard start mode. Once the fuel-air ratio control and O2
trim control have been set, you can switch to the Ign Load TC, IgnPtWithTC or
IgnPtWoutTC option.
Attention!
Burner head with metal mesh can only be operated in the O2 controller operating
mode O2 controller, as, when the O2 controller is deactivated automatically, the
actuators operate along the ratio control curve, which can result in the flame
lifting.
Basic Documentation LMV5...
19 O2 trim control with LMV52 and PLL52
CC1P7550en
22.05.2018