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Building Technologies Basic Documentation LMV5... CC1P7550en
7 Boiler controller / load controller 22.05.2018
7.4.3 Multistage control
When selecting Oil, the LMV5 must be set to 2-stage or 3-stage, depending on the type
of burner, using parameter Operation Mode (refer to chapter Control characteristics).
In these 2 operation modes, the PID algorithm is not required and is not calculated.
Maximum 3 fuel stages are activated and deactivated depending on the actual values,
the parameterized switching differentials_Stage1...3 (refer to chapter Integrated 2-
position controller (R = ON/OFF)), and the parameterized reaction thresholds Q2 and
Q3.
This approach is used to reduce the switching frequency of the higher stages.
∂ The integral of the control deviation over time is generated
∂ Switching on of stage 2 is locked until the temperature has dropped below the
adjustable reaction threshold Q2
∂ Switching on of stage 3 is locked until the temperature has dropped below the
adjustable reaction threshold Q3
If the temperature frequently drops below the switch-on thresholds, the integrals are
added up and the higher stage switched on when the associated Q-value is reached.
If, before that, the setpoint is reached with the lower stage, the counter is reset.
Parameter ThreshStage2On (Q2)
ThreshStage3On (Q3)
Reaction thresholds Q2 and Q3 (integral of control deviation (K) x time (s))
General
Load-dependent
activation of the
higher burner stages
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