Danfoss EKC 202D1 User guide

User Guide

Controller for
temperature control

EKC 202D1

ADAP-KOOL® Refrigeration control systems

Introduction

Application

• The controller is used for temperature control refrigeration
appliances in supermarkets

• With many predened applications one unit will oer you
several options. Flexibility has been planned both for new
installations and for service in the refrigeration trade

Principle

The controller contains a temperature control where the signal
can be received from one or two temperature sensors.
The thermostat sensors are either placed in the cold air ow after
the evaporator, in the warm air ow just before the evaporator,
or both. A setting will determine how great an inuence the two
signals are to have on the control.
A measurement of the defrost temperature can be obtained
directly through the use of an S5 sensor or indirectly through
the use of the S4 measurement. Four relays will cut the required
functions in and out – the application determines which. The
options are the following:

• Refrigeration (compressor or relay)

• Fan

• Defrost

• Rail heat

• Alarm

• Light

The dierent applications are described on page 7.

Advantages

• Several applications in the same unit

• The controller has integrated refrigeration-technical functions,
so that it can replace a whole collection of thermostats and
timers

• Buttons and seal imbedded in the front

• Easy to remount data communication

• Quick set-up

• Two temperature references

• Digital inputs for various functions

• Clock function with super cap backup

Contents

Introduction ....................................................................................................... 2

Operation ............................................................................................................ 3

Applications ....................................................................................................... 7

Survey of functions .......................................................................................... 8

2 Manual RS8FL402 © Danfoss 2015-12 EKC 202D1

Operation .......................................................................................................... 17

Menu survey .....................................................................................................18

Ordering ............................................................................................................21

Connections ..................................................................................................... 22

Data ..................................................................................................................... 23

Operation

Sensors

Up to two thermostat sensors can be connected to the controller.
The relevant application determines how.

A sensor in the air before the evaporator: S3
This connection is primarily used when control is based on area.

A sensor in the air after the evaporator: S4
This connection is primarily used when refrigeration is controlled
and there is a risk of a too low temperature near the products.

A sensor before and after the evaporator: S3 + S4
This connection oers you the possibility of adapting the
thermostat, the alarm thermostat and the display to the relevant
application. The signal to the thermostat, the alarm thermostat
and the display is set as a weighted value between the two
temperatures, and 50% will for example give the same value from
both sensors.
The signal to the thermostat, the alarm thermostat and the display
can be set independently of one another.

Defrost sensor: S5
The best signal concerning the evaporator’s temperature
is obtained from a defrost sensor mounted directly on the
evaporator. Here the signal may be used by the defrost function,
so that the shortest and most energy-saving defrost can take
place.
If 2 (x) S5 sensors are required, an S5B sensor can be mounted
on the DI1 input. Defrosting will stop when both temperature
sensors record a temperature higher than the set defrost stop
temperature.

If a defrost sensor is not required, defrost can be stopped based
on time, or S4 can be selected.

Change of temperature reference

In an impulse appliance, for example, used for various product
groups. Here the temperature reference is changed easily with
a contact signal on a digital input. The signal raises the normal
thermostat value by a predened amount. At the same time the
alarm limits with the same value are displaced accordingly.

EKC 202D1 Manual RS8FL402 © Danfoss 2015-12 3

Digital inputs

There are two digital inputs both of which can be used for the
following functions:

- Case cleaning

- Door contact function with alarm

- Starting a defrost

- Coordinated defrost

- Change-over between two temperature reference

- Retransmission of a contact’s position via data communication

- The DI1 input can receive a signal from an S5B temperature sensor.

Case cleaning function

This function makes it easy to steer the refrigeration appliance
through a cleaning phase. Via three pushes on a switch you
change from one phase to the next phase.
The rst push stops the refrigeration – the fans keep working
”Later”: The next push stops the fans
”Still later”: The next push restarts refrigeration
The dierent situations can be followed on the display.

On the network a cleaning alarm is transmitted to the system unit.
This alarm can be ”logged” so that proof of the sequence of events
is provided.

- + + °C

1 ÷ + Fan

2 ÷ ÷ O

3 + + °C

Door contact function

In cold rooms and frost rooms the door switch can switch the light
on and o, start and stop the refrigeration and give alarm if the
door has remained open for too long.

Overriding of light diagram

(Only for use with circuit diagram 2 in which relay 4 is used to
control the light)
By holding the middle button in for four seconds, the light relay
will change over to the opposite position. An “-L-” will appear in
the display as a conformation.
The override will only apply to the current On or O period. The
next change will follow the planned diagram.
If the light function is set to follow the door function, the override
will not be possible and the door function will be followed.
An override cannot be performed if the regulation is stopped by
the “Main switch” or “Appliance cleaning function”, or if it is await­ing the "Power up delay”.

The middle button is
activated here

Planned change
via diagram

Position of
light relay

The middle button is
activated here

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Defrost

Depending on the application you may choose between the fol­lowing defrost methods:
Natural: Here the fans are kept operating during the defrost
Electric: The heating element is activated
Brine: The valve is kept open so that the brine can ow
through the evaporator
Gas Simple defrost

Start of defrost

A defrost can be started in dierent ways
Interval: Defrost is started at xed time intervals, say, every
eight hour
Refrigeration time:
Defrost is started at xed refrigeration time inter-
vals, in other words, a low need for
refrigeration will ”postpone” the coming defrost
Schedule: Here defrost can be started at xed times of the
day and night. However, max. 6 times
Contact: Defrost is started with a contact signal on a digital
input
Network: The signal for defrost is received from a system unit
via the data communication
S5 temp In 1:1 systems the eciency of the evaporator can

be followed. Icing-up will start a defrost.
Manual: An extra defrost can be activated from the control­ ler’s lower-most button

All the mentioned methods can be used at random – if just one
them is activated a defrost will be started.

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 dened to be the controlling unit and
a battery module may be tted in it so that the clock is ensured
backup.
The controlling unit is the controller with a defrost diagram in­stalled in t1-t6, t11-t16. This is indicated when the “HACCP” symbol
lights up in the front.
When a defrost is started all the other controllers will follow
suit and likewise start a defrost. After the defrost the individual
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. A manual start of the defrost function will only apply to the
current controller.).

Defrost via data communication

All controllers are tted with a data communication module, and
via the override function from a gateway/system manager the
defrost can be coordinated.

Defrost on demand

1 Based on refrigeration time

When the aggregate refrigeration time has passed a xed time,
a defrost will be started.

Max. 15

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

If both an S5 and an S5B sensor are used, defrosting will be initi­ated by the sensor, which detects the lowest temperature.

EKC 202D1 Manual RS8FL402 © Danfoss 2015-12 5

Night time cover function

The controller has a function that automatically detects when a
night time cover has been placed over the refrigeration appliance.
This function requires the use of both an S3 and S4 sensor.
When the night time cover is placed over the appliance, heat
intake and thus the need for increased cooling are reduced. The
temperature dierence between S3 and S4 will be reduced, and
the controller will change to night operation mode once this
dierence becomes less than the set dierence (night time cover
dierence).

Example
During day operation there is a temperature dierence of e.g. 8K
between S3 and S4.
During operating with a night time cover the dierence drops to
e.g. 3 K.
r75 Cover di must be set to a value between the two values. In
this case, 5.5 k.

This function is not active during the following operating
situations:
Interrupted regulation
Appliance cleaning
Defrosting
Pull-down sequence

If the controller registers a negative dierence, it will “see” this as
an inversion of the two sensors. It will therefore send the alarm,
“S3/S4 inverted”.

Night time cover
placed over
appliance

Example of temperature sequence

Example of settings:
r15 Ther S4% = 100%
r61 Ther S4% Night = 0%
r13 Night setback = 3 K
r75 Cover dif = 5 K

Night
time cover
detected

Night
time cover
removed

Removal of
night time
cover detected

This function has no inuence on the light function.

Extra module

• The controller can afterwards be tted with an insertion module
if the application requires it.
The controller has been prepared with 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.

- Data communication

If you require operation from a PC, a data communication mod­ule 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 dis­play will show the same information as the controller's display,
but does not incorporate buttons for operation.

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Applications

Here is a survey of the controller’s eld of application.

A setting will dene the relay outputs so that the controller’s
interface will be targeted to the chosen application.

On page 18 you can see the relevant settings for the respective
wiring diagrams.

S3 and S4 are temperature sensors. The application will deter­mine whether either one or the other or both sensors are to be
used. S3 is placed in the air ow before the evaporator. S4 after
the evaporator.
A percentage setting will determine according to what the
control is to be based. S5 is a defrost sensor and is placed on the
evaporator.
DI1 and DI2 are contact functions that can be used for one of the
following functions: door function, alarm function, defrost start,
external main switch, night operation, change of thermostat ref­erence, appliance cleaning, forced refrigeration or coordinated
defrost. See the functions in settings o02 and o37.

Refrigeration control with one compressor

The functions are adapted to small refrigeration systems which
either may be refrigeration appliances or cold rooms.
The three relays can control the refrigeration, the defrost and the
fans, and the fourth relay can be used for either alarm function,
light control or rail heat control

• The alarm function can be linked up with a contact function
from a door switch. If the door remains open longer than al­lowed there will be an alarm.

• The light control can also be linked up with a contact function
from a door switch. An open door will switch on the light and
it will remain lit for two minutes after the door has been closed
again.

• The rail heat function can be used in refrigeration or freezing
appliances or on the door’s heating element for frost rooms.

The fans can be stopped during defrost and they may also follow
a door switch’s open/close situation.

There are several other functions for the alarm function as well
as the light control, rail heat control and fans. Please refer to the
respective settings.

1

2

The connections shown in applications 1, 2 and 3 are the
recommended connections if an extra display is not installed.

If an extra display (type EKA 163A) is connected, terminal 21
must be used for the display, and solely for the display.

The remaining connections can be made as follows:

3

S5B

If a defrost sensor is connected to the DI1 input, the
sensor must be mounted on terminals 18 and 19.

EKC 202D1 Manual RS8FL402 © Danfoss 2015-12 7

Survey of functions

Function Para-

meter

Normal display

Normally the temperature value from one of the two thermostat sensors S3 or S4 or a
mixture of the two measurements is displayed.
In o17 the ratio is determined.

Thermostat Thermostat control
Set point

Regulation is based on the set value plus a displacement, if applicable. The value is set
via a push on the centre button.
The set value can be locked or limited to a range with the settings in r02 and r 03.
The reference at any time can be seen in ”u28 Temp. ref”

Dierential

When the temperature is higher than the reference + the set dierential, the com­pressor relay will be cut in. It will cut out again when the temperature comes down to
the set reference.

Ref. Dif.

Setpoint limitation

The controller’s setting range for the setpoint may be narrowed down, so that much
too high or much too low values are not set accidentally - with resulting damages.

To avoid a too high setting of the setpoint, the max. allowable reference value must
be lowered.

To avoid a too low setting of the setpoint, the min. allowable reference value must be
increased.

Correction of the display’s temperature showing

If the temperature at the products and the temperature received by the controller are
not identical, an oset adjustment of the shown display temperature can be carried
out.

Temperature unit

Set here if the controller is to show temperature values in °C or in °F.

Correction of signal from S4

Compensation possibility through long sensor cable

Correction of signal from S3

Compensation possibility through long sensor cable

Start / stop of refrigeration

With this setting refrigeration can be started, stopped or a manual override of the
outputs can be allowed.
Start / stop of refrigeration can also be accomplished with the external switch func­tion connected to a DI input.
Stopped refrigeration will give a ”Standby alarm”.

Night setback value

The thermostat’s reference will be the setpoint plus this value when the controller
changes over to night operation. (Select a negative value if there is to be cold ac­cumulation.)

Selection of thermostat sensor

Here you dene the sensor the thermostat is to use for its control function. S3, S4, or a
combination of them. With the setting 0%, only S3 is used (Sin). With 100%, only S4.

Parameter by operation via data
communication

Display air (u56)

Cutout °C

r01 Dierential

r02 Max cutout °C

r03 Min cutout °C

r04 Disp. Adj. K

r05 Temp. unit

°C=0. / °F=1
(Only °C on AKM, whatever the set­ting)

r09 Adjust S4

r10 Adjust S3

r12 Main Switch

1: Start
0: Stop

-1: Manual control of outputs allowed

r13 Night oset

r15 Ther. S4 %

Activation of reference displacement

When the function is changed to ON the thermostat dierential will be increased by
the value in r40. Activation can also take place via input DI1 or DI2 (dened in o02 or
o37).

Value of reference displacement

The thermostat reference and the alarm values are shifted the following number of
degrees when the displacement is activated. Activation can take place via r39 or input
DI

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r39 Th. oset

r40 Th. oset K