Digital Inputs; Forced Closing; Door Contact; Heating Function - Danfoss AK-CC 450 User Manual

User Guide | Controller for appliance control, AK-CC 450

Digital inputs

There are two digital inputs DI1 and DI2 with contact function and
one digital input DI3 with high voltage signal.
They can be used for the following functions:
- Retransmission of contacts position via data communication
- Door contact function with alarm
- Starting a defrost
- Main switch - start/stop of cooling
- Night setback
- Thermostat bands switch
- General alarm monitoring
- Case cleaning
- Forced cooling
- Override of night blinds
- Case shut down
- Coordinated defrost (DI2 only)
- Forced closing of valve (DI 3 only)

Forced closing

The solenoid valve can be closed with an external signal ( "Forced
closing").
If a defrost cycle is in progress, the forced closing status will not be
re-established until the defrost is completed.
The signal can be received from the DI3-input or via the data com-
munication.
During a forced closing the fans can be set to stop or remain in
operation, and a defrost cycle can be set to be permitted (o90).

Door contact

The door contact function can via the digital inputs be defined for
two different applications:
Alarm monitoring
The controller monitors the door contact and delivers an alarm
message if the door has been opened for a longer period than
the set alarm delay.
Alarm monitoring and stop of refrigeration
When the door is opened the refrigeration is stopped, i.e. the
injection, the compressor and the fan are stopped and light
switch on.
If the door remains open for a longer time than the set restart
time, refrigeration will be resumed. This will ensure that
refrigeration is maintained even if the door is left open or if the
door contact should be defective. If the door remains open for
a longer period than the set alarm delay an alarm will also be
triggered.

Heating function

The heating function is used to prevent the temperature
becoming too low, e.g. in a cutting room, etc. The limit for when
the heating function cuts off is set as an offset value under the
current cutout limit for the refrigeration thermostat. This ensures
that refrigeration and heating do not occur simultaneously.
The differential for the heating thermostat has the same value
as for the refrigeration thermostat. To prevent that the heating
thermostat cuts in during short-term drops in air temperature a
time delay can be set for when to change from refrigeration to
heating.
10 | RS8EU702 |
Refrigeration
start
Refrigeration
stop / reference
Neutral zone
Heat stop
Heat start
© Danfoss | ADAP-KOOL® | 2015.10