Siemens LMV51.000B2 - Control (Characteristics); Operating Mode; Integrated 2-Position Controller (C = on; OFF); General

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Siemens Building Technologies Basic Documentation LMV5... CC1P7550en
HVAC Products 6 Temperature or pressure controller (internal load controller LC) 13.08.2004
6.4 Control (characteristics)
The load controller can work in 2 different operating modes:
• Modulating, or
• Multistage
With electronic fuel / air ratio control, modulating or multistage mode must be selected,
depending on the type of burner.
Parameter: Operation Mode (Two-stage / Three-stage / Modulating)
6.4.1 Integrated 2-position controller (C = ON / OFF)
The integrated 2-position controller transmits to the burner control section the internal
information «Heat demand controller» (C = ON / OFF).
Modulating mode:
C = ON when: Actual value ≤ (setpoint ± SD_ModOn)
C = OFF when: Actual value > (setpoint + SD_ModOff)
Multistage mode:
C = ON when: Actual value ≤ (setpoint ± SD_Stage1On)
C = OFF when: Actual value > (setpoint + SD_Stage1Off) or
C = OFF when: Actual value > (setpoint + SD_Stage3Off) = low-fire; always applies
if none of the 2 thresholds Q2 or Q3 has been exceeded
Note: When «SD_*_On» is positive, the switching differential lies above the setpoint.
When«SD_*_On» is negative, the switching differential lies below the setpoint
(LC software version V01.40 or higher).
Parameters: SD_ModOn
SD_ModOff
SD_Stage1On
SD_Stage1Off
SD_Stage2Off
SD_Stage3Off
Operating mode
General
Switching differentials