KGL Operating Manual – VS 3010 BS
2018-07-02
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41 178
4.5 High-pressure / condenser regulation
The cooling of the refrigerant is performed in the condenser by means of the condenser fans. There is a
physical relationship between the high-pressure and the refrigerant temperature. Therefore, the high-pressure
or the condensation temperature can be regulated with the condenser fans. Various types of control (menu 3-2-
2-1) are provided for the high-pressure control:
Step controller
Regulation using enable and disable of condenser capacity stages
Speed controller
Regulation using speed controller (continuous control). The high-pressure control is performed here
using an analogue signal that specifies the required speed to the speed controller.
Combined control - parallel
Regulation using speed controller (continuous control). The high-pressure control is performed here
using an analogue signal that specifies the required speed to the speed controller. The fans are all
connected in parallel to the speed controller; however they can be loaded or unloaded individually.
Combined control - stages
Combination of step controller and continuous control. The high-pressure control is performed here by
enabling or disabling condenser capacity stages and using a speed-regulated fan.
The control type can be configured using the operator terminal, system centre or via a PC. With the operator
terminal, the type of control is configured using the Control Type selection list (menu 3-2-2-1). The condenser
control contains the control, regulation and monitoring functions for the high-pressure circuit.
4.5.1 Neutral zone fan control
Step control
There is no switching of the fan stages in a configurable neutral zone with step control. This neutral zone is
configurable (parameter Neutral Zone, see menu 3-2-2-2).
Continuous control
For continuous fan control, attention is paid to the increase in the tc actual value in the neutral zone. If the tc
actual value within the neutral zone approaches the tc setpoint, a permanent control error is tolerated by the
controller and the adjusting difference (parameter adjust.diff., see menu 3-2-2-1) is not updated.
4.5.2 Control algorithm for fan control
The control algorithm depends on the type of control.
In the wet vapour range, the temperature is a clear function of the pressure: t = f (p, refrigerant). The
controller calculates temperatures for the HP range from the recorded pressures. Temperature
values are used exclusively for the regulation. In the manual, temperatures (t /t ) represent
0 c
pressures (p /p ).
0
c
4.5.3 Control algorithm with step controller
The high-pressure measured via an A/D converter is compared with the setpoint. The following applies:
control error = actual value (tc_ACTUAL) - setpoint (tc_SETPOINT)
In the case of positive control error and increasing pressure, the step switch shifts up one stage. This means
