Siemens LMV36.520 Series - Modulating Operation; Definition of Curves

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Building Technologies Division Basic documentation LMV36... CC1P7544en
Infrastructure & Citiies Sector 11 Electronic fuel-air ratio control 25.09.2013
11.3 Modulating operation
In modulating mode, it is possible to operate 2 actuators and 1 VSD. 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 VSD and fuel actuator in the second
200 ms.
11.3.1 Definition of curves
The fuel-air ratio curves are defined by 10 curvepoints that are firmly distributed across
the output range. The following assignment applies:
Curvepoint Output Meaning
P0 10% Point of ignition, not approached in the operating position
P1 20% Low-fire
P2 30%
P3 40%
P4 50%
P5 60%
P6 70%
P7 80%
P8 90%
P9 100% High-fire
The actuator positions can be set with a resolution of 0.1°.
Between the curvepoints, the positions are interpolated in a linear manner.
Fuel
Air
VSD
100
90
80
70
60
50
40
30
20
10
0
P0 10 % Ignition point
P1 20 % Low-fire
P2 30 % P3 40 % P4 50 % P5 60 % P6 70 % P7 80 % P8 90 %
P9 100 % High-fire
Bild 385e/1109
Figure 74: Definition of curves
No. Parameter
401 Ratio control curves fuel actuator (curve setting only)
402 Ratio control curves air actuator (curve setting only)
403 Ratio control curves VSD (curve setting only)
404 Fuel 1: Ratio control curves fuel actuator (curve setting only)
405 Fuel 1: Ratio control curves air actuator (curve setting only)
406 Fuel 1: Ratio control curves VSD (curve setting only)