Danfoss AK-CC 750A User Manual page 83

Compressor control
The controller has a function that can be used for compressor
control. When the function is selected ON a relay will automatically
follow the status of the thermostat functions. The relay is ON when
the thermostat demands refrigeration. If the thermostat function
is selected OFF the compressor output will constantly be ON.
A minimum ON time and a minimum restart time for the relay
belong to the function.
The relay will be OFF during defrost.
There is display of:
- operating hours during the past 24 hours
- total number of operating hours
- number of couplings during the past 24 hours
- total number of couplings
Appliance cleaning
This function makes it easy for the shop's staff to carry out a
cleaning of the appliance according to a standard procedure.
Function
Appliance cleaning is activated via a pulse signal of minimum
three seconds' duration – as a rule via a key switch placed on the
appliance. It can however also be activated via data communica-
tion. Appliance cleaning is carried out via three phases:
1 - at the first activation the refrigeration is stopped, but the fans
keep on operating in order to defrost the evaporators. "Fan" is
shown on the display.
2 - at the second activation the fans are also stopped and the
appliance can now be cleaned. "OFF" is shown on the display.
3 - At the third activation refrigeration is recommenced. The
display will show the actual appliance temperature.
To carry out cleaning of a frost appliance as quickly as possible
cleaning can be started with a defrost sequence.
When appliance cleaning is activated a cleaning alarm is trans-
mitted to the normal alarm recipient. A later processing of these
alarms will document that the appliance has been cleaned as
often as planned. The function saves information on when the last
appliance cleaning was carried out and how long it lasted.
Appliance shutdown
This function makes it possible to shut down a refrigeration appli-
ance using data communication or a switch signal.
When the signal is received, refrigeration and alarm monitoring
stops.
Fans and lights will do the following depending on the setup:
• Fans continue. The light will follow the standard setup.
• Fans stop immediately. The light immediately switches off.
• Fans stop when the delay time expires. The light will follow the
standard light control.
• Fans stop when the delay time expires. The light switches off
when the delay time expires.
The shutdown delay time is adjustable and applies to both fans
and lights.
Any night curtain output will follow the light function.
AK-CC 750A RS8HP102 © Danfoss 2018-09
Door contact
The door contact function can be defined for two different
applications:
- Door alarm
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.
- Stop of refrigeration + door alarm
When the door is opened the refrigeration is stopped, i.e. the
injection and the fan are stopped. 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 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 sounded.
In both applications the alarm function will also contain a local
reminder which is activated when 75% of the set time has been
passed. This reminder only appears on the connected display and
the intention of it is that the door must be closed before the alarm
for open door is released.
From the controller the following can be read:
- the duration of the last open period
- the total open period during the past 24 hour
- number of openings during the past 24 hours
Defrost has higher priority than the door function. That is to say,
refrigeration and fans will not be started until defrost is complete.
The door contact function can also activate the light function so
that the light is turned on and kept on for a period of time after
the door has again been closed. Cf. the section on light function.
Light function
The function can be used for controlling the light in a refrigeration
appliance or in a cold room. It can also be used for controlling a
motorised night curtain.
The light function can be defined in three ways:
- the light is controlled via a signal from a door contact. Together
with this function a time delay can be set so that the light is kept
burning for a period of time after the door has been closed.
- the light is controlled via the day/night function
- the light is controlled via the data communication from a system
unit.
It is possible to set whether the light is to be switched on or off
when the main controller switch is activated.
This is set in the function "Light at main switch=off".
If "Light at main switch=off" is set to ON, the normal light function
will be maintained when the main switch is switched off.
If OFF is selected for this setting, the light will stay off when the
main switch is switched off.
Night blind
Motorised night blind can be controlled automatically from the
controller. The night blinds will follow the status of the light
function. When the light is switched on, the night blinds opens
and when the light is switched off, the night blinds close again.
When the night blinds are closed, it is possible to open them using
a switch signal on the digital input. If this input is activated, the
night blinds will open and the refrigeration appliance can be filled
with new products. If the input is activated again, the blinds close
again.
When the night blind function is used, the thermostat function
can control with different weighting between the S3 and S4
sensors. A weighting during day operation and another when the
blind is closed.
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