Electronic Air-Fuel Ratio Control; General; Behavior Outside The Operating Positions; Traveling Speed - Siemens LMV37.4 Series Basic Documentation

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10 Electronic air-fuel ratio control

10.1 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 and 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.

10.2 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.

10.2.1 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).

10.2.2 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
501.00
502.00
503.00
Basic documentation LMV37.4...
10 Electronic air-fuel ratio control
Actuator
Home position fuel actuator
Home position air actuator
No-load speed VSD
CC1P7546en
20.09.2013