Modulating Operation; Definition Of Curves - Siemens LMV27.100x2 Basic Documentation

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10.3

Modulating operation

In modulating mode, it is possible to operate 2 actuators. The burner's output can be
regulated between 20.0% (low-fire) and 100.0% (high-fire) in increments of 0.1%. Since
the actuators are never allowed to operate simultaneously, the output is increased in
small steps of 1%. In the case of an operating ramp of 20% after 100% in 32 seconds,
this represents 1 step in 400 ms. Within such an output step, the air actuator is operated
in the first 200 ms, and the fuel actuator in the second 200 ms.
10.3.1

Definition of curves

The air-fuel ratio curves are defined by 10 curvepoints that are fixed and distributed
across the output range.
The following assignment applies:
Curvepoint Output
P0 10%
P1 20%
P2 30%
P3 40%
P4 50%
P5 60%
P6 70%
P7 80%
P8 90%
P9 100%
The actuator positions can be set with a resolution of 0.1°.
Between the curvepoints, the positions are interpolated in a linear manner.
100
90
80
70
60
50
40
30
20
10
0
Figure 63: Definition of curves
No. Parameter
401 Ratio control curve fuel actuator (only curve setting)
402 Ratio control curve air actuator (only curve setting)
Basic Documentation LMV27...
10 Electronic air-fuel ratio control
Meaning
Point of ignition, not approached in the operating position
Low-fire
High-fire
Fuel
Air
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CC1P7541en
17.12.2018