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Building Technologies
Basic Documentation LMV5...
CC1P7550en
7 Boiler controller / load controller
22.05.2018
7.4.2 Modulating control
When selecting
Gas
, the LMV5 will automatically operate in modulating mode. For this
reason, parameterization is not required when firing on gas.
When selecting
Oil
, the operating mode is to be set to
modulating,
if required, using
parameter
Operation Mode
of the electronic fuel-air ratio control system.
In this operation mode, the load controller calculates the manipulated variable by
means of a PID algorithm, depending on the control deviation.
Example 1: The load is very small so that the controller must switch to ON/OFF mode.
Setpoint
Actual value
7550f07E/0502
R=ON
Y=OPEN
Y=CLOSED
W
SD_ModOff
SD_ModOn
Figure 53: Modulating control – function diagram example 1
Example 2: The load is greater than the amount of heat produced by the burner under
low-fire conditions, thus enabling correct modulating operation.
Setpoint
Actual value
7550f08E/0502
R=ON
Y=OPEN
Y=CLOSED
W
SD_ModOff
SD_ModOn
Figure 54: Modulating control – function diagram example 2
General
Function diagrams