Danfoss AK-PC 351 User Manual page 9

No. of running comp.
Po Pressure
To Saturated temp.
S4 media temp.
MC Po offset
Pc Pressure
Tc Saturated temp.
Day / Night status
LP switch
HP switch
Injection ON
MC Night Setback
Control settings
Control mode
Setpoint
Neutral zone
Night offset
Max Reference
Min Reference
PI control selection
First step runtime
Pump down
Emergency cap. day
Emergency cap. night Emergency capacity in the event of a malfunction of the regulation sensor (suction pressure
Comp. start delay
Injection OFF delay
Configuration
Control sensor
AK-PC 351
The number of compressors in operation can be read here
The measured pressure for the Po pressure transmitter can be read here
The measured Po pressure converted to temperature can be read here
The measured S4 sensors actual value can be read here
The size of a reference displacement on Po required from the system unit
(suction pressure optimisation function) can be read here
The measured pressure for pressure transmitter Pc can be read here
The measured Pc pressure converted to temperature can be read here
The status of the day/night function can be read here
The measured status on the connected low pressure switch can be read here
The measured status on the connected high pressure switch can be read here
The status of the injection ON signal sent via the system unit to the evaporator controllers
can be read here
The status of the night increase signal received from the system device can be read here
Regulation settings
Regulation type
The regulation is normally set to "Auto", but it can be changed to "Off" or "Manual".
When setting to "Manual", a forced capacity setting can subsequently be entered in %.
Enter the set point for the regulation (regulation reference = set point + different offsets) here
An offset can originate from a night increase signal or from an override function on the
system device.
Set the neutral zone around the reference here. Also see the illustration on page 3.
If necessary, set the value by which the reference will be raised at night.
Keep the setting at 0 if regulating with Po optimisation from a system device.
Set the highest permissible regulation reference here
Set the lowest permissible regulation reference here
Set how quickly the PI regulation must react here: 1 = slowly, 10 = very quickly.
(For "Custom" setting 0, the special settings options will open, i.e. Kp, Tn and time settings
around the neutral zone. These options are only for trained staff.)
At start-up, the cooling system must have time to cool down before PI regulation takes over
the regulation role and can cut in the next compressor step.
Set the time before the next compressor may be started here.
Pump-down function
To avoid too many compressor starts/stops at a low load, it is possible to define a pump-
down function for the last compressor. In this case, the compressor will only be cut out when
the current suction pressure is down at the set "Pump-down limit Po".
(The setting must be greater than the safety limit for low suction pressure "Po Min Limit".)
Emergency capacity in the event of a malfunction of the regulation sensor (suction pressure
sensor)
Set the desired capacity that will apply during daytime operation.
sensor)
Set the desired capacity that will apply during night operation.
Delay of compressor start after forced closing of expansion valves (at the end of a forced
close signal)
The delay will result in the system device receiving a start signal for all the evaporator con-
trols involved before the first compressor is started.
Delay of the forced closing of expansion valves, if the controller calls for cut in of compres-
sors, but the compressors are in a locked situation and therefore cannot start.
Configuration
Select the regulating sensor for the suction circuit:
• Pressure transmitter Po - Ratiometric (AKS 32R), 1-5V (AKS 32), 0-20mA, 4-20mA (AKS 33)
• Temperature sensor S4 (brine regulation). (Pt 1000 ohm)
User Guide RS8GZ302 © Danfoss 2015-06
MAN / OFF / AUTO
Fac: AUTO
Min: 0 %
Max: 100%
Min: -80°C (-1.0 bar)
Max: 30°C (50 bar)
Fac: -15°C (3.5 bar)
Min: 0,1 K (0.1 bar)
Max: 20 K (5.0 bar)
Fac: 6 K (0.4 bar)
Min: -25 K (-5.0 bar)
Max: 25 K (5.0 bar)
Fac: 0 K (0.0 bar)
Min: -50°C (-1.0 bar)
Max: 80°C (50.0 bar)
Fac: 80°C (40.0 bar)
Min: -80°C (-1.0 bar)
Max: 25°C (40.0 bar)
Fac: -80°C (-1.0 bar)
Min: 0 (custom)
Max: 10
Fac: 5
Min: 0 s
Max: 300 s
Fac: 120 s
Yes /No
Fac: No
Min: -80°C (-1.0 bar)
Max: 30°C (50.0 bar)
Facb: -40°C (0.3 bar)
Min: 0 %
Max: 100%
Fac: 50%
Min: 0 %
Max: 100%
Fac: 25%
Min: 0 s
Max: 180 s
Fac: 30 s
Min: 0 s
Max: 300 s
Fac: 120 s
AI-demand
Po / S4
Fac: Po ratiometric
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