Building Technologies Division
Infrastructure & Citiies Sector
11
Electronic fuel-air ratio control
11.1 General
Electronic air-fuel ratio control is used to control the burner's actuators depending on
burner output. It is possible to connect 2 actuators and, optionally, 1 VSD. Resolution is
0.1° with the actuators and 0.1% with the VSD. Output can be regulated in increments of
0.1% in modulating mode or with a maximum of 3 stages in multistage mode.
To reduce the electric power required for the actuators, they are never operated
simultaneously, but in successive order, or alternately.
11.2 Behavior outside the operating positions
Outside their operating positions, the actuators approach the different positions in
successive order. The program phase determines the position to be approached.
11.2.1 Traveling speed
The running speed of the actuators is fixed at 5 seconds for a positioning angle of 90°
for SQM33.4, SQM33.5, and SQN1.
The speed is 10 seconds for a positioning angle of 90° for SQM33.6.
The SQM33.7 requires 17 seconds for a positioning angle of 90°.
The ramp speed of the VSD can be adjusted separately for higher and lower speeds.
No.
Parameter
522
Ramp up
523
Ramp down
The setting also applies to the operating position (refer to chapter Operating position).
11.2.2 Home position
This position is approached in the Home run (10), Standby (12) and Lockout position
(00) phases.
The position can be set via the following parameters:
Parameter
Actuator
501.00
No-flame positions fuel actuator: Home position
502.00
No-flame positions air actuator: Home position
503.00
No-flame speeds VSD: No-load speed
504.00
Fuel 1: No-flame positions fuel actuator: Home position
505.00
Fuel 1: No-flame positions air actuator: Home position
506.00
Fuel 1: No-flame speeds VSD: No-load speed
Basic documentation LMV36...
11 Electronic fuel-air ratio control
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CC1P7544en
25.09.2013