Lumina 38
Explanation control functions
10
Linear controlled fans have a minimum ventilation level, for example 30%. This determines below what
percentage the ventilation will modulate, and the ventilation level during modulating. If, for example, the calculated
output of the linear part is 10%, ventilation will run for 10/30th of the cycle time at 30%, and not run for the rest of
the time.
With this type of control enter the fixed cycle time (ON- plus OFF-time). The total cycle is as follows:
Example modulating control with fixed ON-time
Cycle time
:
10 minutes
Modulate below %
:
30%
Control value ventilation
: 15%
If the control value ventilation is lower than 30%, the control computer will use modulating ventilation.
The controllable part will be active for half of the cycle time of 10 minutes, with a ventilation level of
30%. This means an ON-time of 5 minutes and an OFF-time of 5 minutes. The control computer always
controls based on these times.
With optimal modulating control the control computer aims for an optimal ON-time and an optimal OFF-time
entered by the installer. The examples below shows that the switch off moment and cycle time can vary:
Example - Optimum modulating control (1)
Optimum ON-time
:
2 minutes
Maximum cycle time
:
10 minutes
Modulate below %
:
30%
Control value ventilation
: 15%
If the control value ventilation is lower than 30%, the control computer will use modulating ventilation.
The control computer assumes an optimum ON-time of 2 minutes and a ventilation level of 30%. This
means that the optimum ON-time of 2 minutes must be half of the total cycle time. The control computer
calculates a cycle time of 2 x 2 = 4 minutes (2 minutes on and 2 minutes off). In this example the OFF-
time will also be 2 minutes.
Example - Optimum modulating control (2)
Optimum ON-time
:
2 minutes
Maximum cycle time
:
10 minutes
Modulate below %
:
30%
Control value ventilation
: 3%
The control computer assumes an optimum ON-time of 2 minutes. This means that the optimum ON-
time of 2 minutes must be a tenth (=3/30) of the total cycle time. The control computer calculates a
cycle time of 10 x 2 minutes = 20 minutes (2 minutes on and 18 minutes off). However, this is longer
than the maximum cycle time of 10 minutes.
The control computer will calculate new ON- and OFF-times based on the maximum cycle time as
follows: 1/10 of 10 minutes means an ON-time of 1 minute. The rest of the time the control remains
switched off.
Summary of Contents for LUMINA 38
Page 1: ...g...
