KGL Operating Manual – UA 412 S
2019-01-14
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5.5.2.2 Controller type SPIR290
The cooling requirement is regulated by up to 4 compressors for the controller type SPIR290. The number of
compressors can be configured from 1 to 4. The compressor enable is set in the case of existing cooling
requirement and inactive compressor lock. If the minimum standstill time for at least one compressor has
elapsed, the PID regulation for the calculated speed is enabled for the compressors. When the PID controller
is enabled, the speed in the range of 0 to 100% for the compressors is calculated from the current supply air
temperature and the setpoint supply air temperature.
The number of compressors (1 to 4) and the regulation with or without FC compressors (Y/N) are configured in
menu 6-2-7.
SPIR290 without FC compressors
The calculated speed determines the switching on and switching off of the up to 4 compressors based on fixed
switching thresholds. The calculated speed is shifted to the compressor stages as described.
Switch off below
Switch on starting from
Compressor 1
5%
20%
Compressor 2
40%
55%
Compressor 3
60%
75%
Compressor 4
80%
95%
SPIR290 without FC compressors
The calculated speed determines the switching on and switching off of the up to 4 compressors. The threshold
value of the switch-on of a compressor is configured using the parameter "Limit combi" (menu 6-7). The
threshold value for switch-off of a compressor is the configured minimum speed (menu 6-2-7).
If the calculated speed exceeds the threshold value for switching on a compressor, the compressor whose
minimum standstill time has elapsed is switched on and the compressor with the lowest total run time of all
compressors that can still be switched on. With the switch-on of a compressor, the I-component of the PID
controller is corrected so that the calculated speed adopts the minimum speed.
If the calculated speed undercuts the threshold value for switching off a compressor, the compressor whose
minimum run time has been exceeded is switched off and the compressor with the longest total run time of all
switched-on compressors. With the switch-off of a compressor, the I-component of the PID controller is
corrected so that the calculated speed adopts the threshold value for switching on.
