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Firmware V1.41 V1
08.11.2022
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The fans are also loaded one after the other with the
KKKG
switching mode. This results in all fans being
loaded at low speed (star operation). Afterwards, all fans are switched to the high speed (delta operation).
All fan outputs are unloaded simultaneously when shifting down the capacity stages. Afterwards, all fans are
loaded again one after the other at the low speed after a configurable time delay. After this, the low speeds are
unloaded one after the other.
The following table shows the control of the fan outputs using the example of a system with three fans and four
fan stages:
Switching sequence KKKG
Fan stage:
L1
S1
L2
S2
L3
S3
Star/
Δ
S4
Shifting up
Fans 1, 2 and 3 OFF
•
Fan 1 low speed / Fans 2 and 3 OFF
•
•
Fans 1 and 2 low speed / Fan 3 OFF
•
•
•
Fans 1, 2 and 3 low speed
•
•
•
•
Fans 1, 2 and 3 high speed
Shifting down
All fans OFF
•
•
•
Fans 1, 2 and 3 low speed
•
•
Fans 1, 2 low speed / Fan 3 OFF
•
Fan 1 low speed / Fans 2 and 3 OFF
All fans OFF
The time delay for the switching from delta to star operation can be set using the parameter
Del. slow speed
(menu 3-2-2-1). In the
KKGG
and
KKKG
operating modes, the switching to high speed during night operation
can be disabled to prevent noise using the parameter
Fast speed N
(menu 3-2-2-1).
If the gas cooler outlet temperature exceeds the setpoint specified in
t
G
-Max
(menu 3-2-2-1), the high speed is
loaded independently from the parameter described above. The fans do not switch back to the low speed again
until the capacity stages are shifted down due to the falling pressure.
5.6.6 Control Algorithm tG with Speed Control
The gas cooler outlet temperature measured via an A/D converter is compared with the setpoint. The following
applies:
In the case of a positive control error, a speed setpoint is calculated using a PI control algorithm that is
activated on the speed controller via an analogue output (0-10 V). The speed controller regulates the fan speed
to the specified setpoint.