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Technical Information
137 - 145
Adaptive superheat control PID parameters
In case an electronic expansion valve is used (configured in parameter
68 Valve type
) the superheat is
controlled by an adaptive PID controller. This parameters define proportional, integral and differential part of
the controller. Also the stability is evaluated continuously. In case the controller is becoming unstable the
controller parameters are adapted.
146 Adjust opening threshold
In case the compressor speed is changing the EXV must follow very fast to keep a stable superheat. This is
done by a feedforward control reacting on regular EXV controller. If the increasing in speed is above the value
defined in this parameter, the feedforward control is activated. The value is set in percent of the maximum
speed rate in capacity control
135 Speed rate capacity control.
147 Adjust opening factor
The additional opening of the EXV done by feed forward control is calculated by the difference between the
increasing in speed and the threshold configured in parameter
146 Adjust opening threshold
. An adjustment
between the valve opening (0
– 100 %) and the acceleration rate ( 0 – 100% of
135 Speed rate capacity
control
) can be done by this parameter.
148 Oil return speed
To guarantee that no oil is not settling in the evaporator when running a variable speed compressor on low
speed for a longer time an oil return should be forced after a certain time. The speed of the compressor when
running in oil return mode is defined by this parameter.
149 Oil return threshold
When the compressor stays below the speed configured in this parameter for a duration longer than the time
configured in parameter
150 Oil return duration
an oil return is triggered.
150 Oil return duration
During an oil return the Compressor is running with speed configured in parameter
148 Oil return speed
for a time set by this parameter.
151 Oil return threshold duration
The time the compressor is running with a speed below the value configured in parameter
149 Oil return
threshold
is accumulated. When the compressor speed rises above the threshold the duration timer is paused.
If the speed drops again below the threshold level the timer continuous running. The timer is only reset if an
oil return is triggered or a second timer running in parallel (also when the speed is above the threshold) expires.
152 Capacity control Kp
If a variable speed compressor is used (
121
Compressor command type
is set to Drive) the
temperature / capacity control is done by a PI controller
152
Capacity control Kp
and
124 Capacity
control Ki
). The compressor speed (capacity) is controlled by a PI controller. This parameter defines the
proportional part.
153 Demand defrost trigger correction
When a variable speed compressor is used the compressor speed is included in the defrost detection
algorithm. By increasing this factor the impact of the compressor speed on the delta detection gets more heavy
(see Parameter
52
).
154 Compressor Code
In a variable speed application the package of compressor, drive and envelope has to be set by this parameter.
According to this code the drive is initialized.
155 Digital input door
The corresponding digital input (DI 1 or DI 2) for a door contact can be set by this parameter.
156 Contact logic door
The door input can be configured with a normally open or normally closed contact logic.
157 Restart delay open door
If the door is open the cooling is stopped immediately and after the door is closed cooling is restarted. In case
the door stays open for a period longer than the time defined by this parameter, cooling is restarted even when
the door is still open.
158
„Door open“ alarm delay
If the door is open the cooling is stopped immediately. In case the door stays open for a period longer than the
time defined by this parameter an Alarm is triggered.
