AK-HP 780
Heat pump controller RS8GF202 © Danfoss 2015-08
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A bit more about the functions
Compressor
Regulation of up to 8 compressors. And up to 3 unloaders each
compressor.
Compressor No. 1 or 2 can be speed-regulated.
A signal is required from pressure transmitters P0 and Pd.
A signal is required from temperature sensors Ss and Sd.
P0 is also used to protect against a too low pressure.
Pd is also used to protect against a too high pressure.
Temperature reference
Sctrl is used as a regulating sensor.
The cut in and cut out of the compressors is determined by the
measured temperature.
Receiver
S7 is used as a regulating sensor.
One pump can be controlled based on the measured signal. Sig-
nals can be delivered so that the pump can be speed-controlled.
Speed regulation
The function requires an analog output module.
A relay output may be used for start/stop of the speed regulation.
Safety circuit
If signals are to be received from one or more parts of a safety
circuit, each signal must be connected to an ON/OFF input.
Day/night signal for lowering the temperature reference Sctrl.
The clock function can be used, but an external ON/OFF signal
may be used instead.
Separate thermostat and pressure control functions
A number of thermostats can be used according to your wishes.
The function requires a sensor signal and a relay output. In the
controller there are settings for cutin and cutout values. An associ-
ated alarm function may also be used.
Separate voltage measurements
A number of voltage measurements can be used according to
your wishes. The signal can for example be 0-10 V. The function
requires a voltage signal and a relay output. In the controller there
are settings for cutin and cutout values. An associated alarm func-
tion may also be used.
If you want to know more about the functions, go to
chapter 5.
Connections
Here is a survey of the possible connections. The texts can be read
in context with the table on page 31.
Analog inputs
Temperature sensors
• Sctrl
Must always be used as a regulating sensor for compressor
regulation.
• Ss (suction gas temperature)
Must always be used.
• Sd (discharge gas temperature)
Must always be used.
• S7 (receiver temperature)
Must always be used for regulation sensor for pump control.
• Saux (1-5), any extra temperature sensors
Up to five additional sensors for monitoring and data collec-
tion may be connected. These sensors can be used for general
thermostat functions.
Pressure transmitters
• P0 Suction Pressure
Must always be used.
• Pd Discharge pressure
Must always be used.
• Prec. Oil receiver pressure. Must be used for oil receiver pressure
regulation.
• Paux (1-5)
Up to 5 extra pressure transmitters can be connected for moni-
toring and data collection.
These sensors can be used for general pressure switch functions.
Note. A pressure transmitter type AKS 32 or AKS 32R can supply
signals to a maximum of five controllers.
Voltage signal
• Ext. Ref
Used if a reference override signal is received from another
control.
• Voltage inputs (1-5)
Up to 5 extra voltage signals can be connected for monitoring
and data collection. These signals are used for general voltage
input functions.
On/Off-inputs
Contact function
(on an analog input) or
voltage signal
(on an extension module)
• Common safety input for all compressors (e.g. common high-
pressure/low-pressure pressure switch)
• Up to 6 signals from the safety circuit of each compressor
• Signal from the pumps safety circuit
• Any signal from the frequency converter’s safety circuit
• External start/stop of regulation
• External day/night signal (raise/lower the Sctrl- reference).
• DI alarm (1-10) inputs
Up to 10 no. extra on/off signals for general alarm for monitoring
and data collection can be connected.
On/off-outputs
Relay outputs
• Compressors
• Unloaders
• Pump
• Start/stop of liquid injection in heat exchanger
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