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Building Technologies Division User Manual LMS14… CC1U7471en
6 The settings in detail 28.01.2015
6.34.8 Setpoint filter for fan speed control
Line no. Operating line
[3694.1] Pt1 time const 1 drop
[3695.1] Pt1 time const 2 drop
[3696.1] Pt1 time const 3 drop
These are the filter time constants for the speed setpoint of fan control when
modulating from a higher to a lower speed level. The time constants act depending on
parameters Pt1 upper spd falling [3698.1] and Pt1 lower spd falling [3699.1] and –
when modulating down – can be subdivided into 3 ranges.
Line no. Operating line
[5283.1]
Pt1 time const 4 drop
Filter time constant for the speed setpoint of fan control when modulating from a higher
to a lower level.
The time constant acts in all phases, with the exception of TI and MOD, depending on
the parameters Diff setpoint filter [5285.1] (= Yes).
Parameter Diff setpoint filter [5285.1] is deactivated when set to No.
Line no. Operating line
[5284.1]
Pt1 time const 1 incr
Filter time constant for the speed setpoint of fan control when modulating from a lower
to a higher level.
The time constant acts in all phases, with the exception of TI and MOD, depending on
the parameters Diff setpoint filter [5285.1] (= Yes).
Parameter Diff setpoint filter [5285.1] is deactivated when set to No.
Line no. Operating line
[3697.1] Pt1 time const 2 incr
Filter time constant for the speed setpoint of fan control when modulating from a lower
to a higher speed level.
Line no. Operating line
[5285.1]
Diff setpoint filter
No
Yes
Selection parameter, which can be used to load different setpoint filter time constants to
the PT1 setpoint filter, depending on the sequence of phases.
If Diff setpoint filter [5285.1] is set to No) the parameters with Pt1 time const 1 drop
[3694.1], Pt1 time const 2 drop [3695.1], Pt1 time const 3 drop [3696.1] and Pt1 time
const 2 incr [3697.1] are used in all phases.
If Diff setpoint filter [5285.1] is set to Yes, the parameters with Pt1 time const 1 drop
[3694.1], Pt1 time const 2 drop [3695.1], Pt1 time const 3 drop [3696.1] and Pt1 time
const 2 incr [3697.1] are used in phases TI and MOD.
In all other phases, Pt1 time const 4 drop [5283.1] and Pt1 time const 1 incr [5284.1]
are used.
Pt1 time const x drop
Pt1 time const 4 drop
Pt1 time const 1 incr
Pt1 time const 2 incr
Diff setpoint filter