Danfoss AK-CC 460 User Manual page 7

User Guide | Controller for SemiPlugin appliance, AK-CC 460
Railheat
It is possible to pulse-control the power to the rail heat in order to
save energy. Pulse control can either be controlled according to
day/night load or dew point.
Pulse control according to day and night
Various ON periods can be set for day and night operation.
A period time is set as well as the percentage part of the period in
which the rail heat is ON.
Pulse control according to dew point
In order to use this function a system manager of the type AK-SM
is required which can measure dew point and distribute the cur-
rent dew point to the appliance controllers. For this the rail heat's
ON period is controlled from the current dew point.
Two dew point values are set in the appliance control:
• One where the effect must be max. i.e.100%. (o87)
• One where the effect must be min. (o86).
At a dew point which is equal to or lower than the value in 086, the
effect will be the value indicated in o88.
In the area between the two dew point values the controller will
manage the power to be supplied to the rail heat.
During defrosting
During defrosting the rail heat will be controlled by the setting in
"d27" (Off, On or pulsing).
Fan
Pulse control
To obtain energy savings it is possible to pulse control the power
supply to the evaporator fans.
Pulse control can be accomplished in one of the following ways:
- during the thermostat's cutout period (cold room)
- during night operation and during the thermostat's cutout pe-
riod (appliance with night lid /blind)
A period of time is set as well as the percentage of this period of
time where the fans have to be operating.
Cutout of fans during plant breakdowns
If the refrigeration in a breakdown situation stops, the temperature
in the refrigeration appliance may rise as a result of the power
supply from fans. In order to prevent this situation the controller
can stop the fans if the temperature at S5 exceeds a set limit value.
Variable speed compressor control
The variable speed compressor control is using these 3 settings:
- Start speed - c47. After starting the compressor, this speed will
be maintained for 10 seconds. Hereafter the speed can vary
between min. and max speed
- Max. speed – c48. The max allowed speed for the compressor
- Min. speed – c46. At low requested capacity, the set minimum
speed will be maintained until the compressor is cut out.
Note: the voltage on the analogue output is scaled for the
maximum frequency range from min. speed to 100 Hz, meaning
that if the max. speed is set lower than 100 Hz, the max. output
voltage will be below 10 V.
© Danfoss | DCS (vt) | 2019.12
Rail heat
AO
0 – 10 V
10 V
V Max.
Active voltage range
V Start
V Min.
Fmin Fstart
c46 c47
Dew point
Fmax 100 Hz
c48
BC230086440483en-000201 | 7