Danfoss EKC 202D Manual page 5

Coordinated defrost
There are two ways in which coordinated defrost can be arranged.
Either with wire connections between the controllers or via data
communication.
Wire connections
One of the controllers is defined to be the controlling unit and
a battery module may be fitted in it so that the clock is ensured
backup. When a defrost is started all the other controllers will
follow suit and likewise start a defrost. After the defrost the indi-
vidual controllers will move into waiting position. When all are in
waiting position there will be a change-over to refrigeration.
(If just one in the group demands defrost, the others will follow
suit).
Defrost via data communication
All controllers are fitted with a data communication module,
and via the override function from a gateway the defrost can be
coordinated.
Defrost on demand
1 Based on refrigeration time
When the aggregate refrigeration time has passed a fixed time,
a defrost will be started.
2 Based on temperature
The controller will constantly follow the temperature at S5.
Between two defrosts the S5 temperature will become lower
the more the evaporator ices up (the compressor operates for a
longer time and pulls the S5 temperature further down). When
the temperature passes a set allowed variation the defrost will
be started.
This function can only work in 1:1 systems
Extra module
• The controller can afterwards be fitted with an insertion module
if the application requires it.
The controller has been prepared with a plug, so the module
simply has to be pushed in
- Battery module
The module guarantees voltage to the controller if the supply
voltage should drop out for more than four hours. The clock
function can thus be protected during a power failure.
- Battery and buzzer module
As above + sound buzzer
- Data communication
If you require operation from a PC, a data communication mod-
ule has to be placed in the controller.
• External display
If it is necessary to indicate the temperature on the front of
refrigeration appliance, a display can be mounted. The extra dis-
play will show the same information as the controller's display,
but does not incorporate buttons for operation.
EKC 202D Manual RS8EE202 © Danfoss 08-2010 5