Multistage Operation; Definition Of Curves; Running Speed - Siemens LMV37.4 Series Basic Documentation

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9.4 Multistage operation

This operating mode is only available when firing on oil. There is a choice of 2-stage and
3-stage operation. Hence, the burner's output can be regulated via 2 or 3-stages. Modu-
lation is accomplished by adjustment of the air actuator or of VSD and by switching the
fuel valves for changing the amount of fuel delivered.

9.4.1 Definition of curves

Air-fuel ratio control is defined via the 2 or 3 static output points. To switch the valves on
and off, switch-on and switch-off points must be defined.
The following assignment is used:
Curve- Meaning
point
P0 Point of ignition (does not approached in the running position)
P1 Stage 1
P2on Switch-on point stage 2. When this point is exceeded, the fuel
valve for the second stage is switched on
P2_d Presetting of point P2 with no approach
P2 Stage 2
P2of Switch-off point stage 2. When this point is crossed, the fuel valve
for the second stage is switched off
P3on Switch-on point stage 3. When this point is exceeded, the fuel
valve for the third stage is switched on
P3_d Presetting of point P3 with no approach
P3 Stage 3
P3of Switch-off point stage 3. When this point is crossed, the fuel valve
for the third stage is switched off
The actuator positions can be set with a resolution of 0.1°, the speeds with a resolution
of 0.1%.

9.4.2 Running speed

The air actuator or the VSD is operated like outside the running position. The defined
ramp speeds are used.
The running speed of the actuators is fixed at 5 seconds for a positioning angle of 90°.
For increasing or degrading the speed, the speed of the VSD can be separated ad-
justed.
No. Parameter
522 Ramp up
523 Ramp down
The setting also acts outside the operating position.
Basic documentation LMV37.4...
9 Electronic air-fuel ratio control
Valve
V1
V1
V1
V1
V2
V2
V2
V2
V3
V3
CC1P7546en
01.12.2009