Danfoss AK-CC 350 User guide

User Guide

Controller for temperature control

AK-CC 350

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 many
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

• Fans for hotgas defrost

• Refrigeration 2 (compressor 2 or relay 2)

The dierent applications are described on page 6.

Advantages

• Many applications in the same unit

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

• Can control two compressors

• Fixed MODBUS data communication

• Quick setup

• Two temperature references

• Digital inputs for various functions

• Clock function with super cap backup

• HACCP (Hazard Analysis and Critical Control Points)

- Temperature monitoring and registration of period with too
high temperature (see also page 19)

- Factory calibration that will guarantee a better measuring
accuracy than stated in the standard EN 441-13 without
subsequent calibration (Pt 1000 ohm sensor)

Contents

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

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

Applications ....................................................................................................... 6

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

Operation .......................................................................................................... 18

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Menu survey .....................................................................................................20

Ordering ............................................................................................................23

Connections ..................................................................................................... 24

External display ............................................................................................... 25

Data ..................................................................................................................... 26

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:
This connection is primarily used when control is based on area.

A sensor in the air after the evaporator:
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:
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
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 a defrost sensor is not required, defrost can be stopped based
on time, or S4 can be selected.

Control of two compressors

This control is used for controlling two compressors of the same
size. The principle for control is that one of the compressors
connects at ½ the dierential of the thermostat, and the other at
the full dierential. When the thermostat cuts in the compressor
with the fewest operating hours is started. The other compressor
will only start after a set time delay, so that the load will be
divided between them. The time delay has a higher priority than
the temperature.
When the air temperature has dropped by half the dierential the
one compressor will stop, the other will continue working and not
stop until the required temperature is achieved.
The compressors used must be of a type that is capable of starting
up against a high pressure.

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.

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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

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.

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
Hot gas: Here the solenoid valves are controlled so that the
hot gas can ow through the evaporator

Start of defrost

A defrost can be started in dierent ways
Interval: Defrost is started at xed time intervals, say, every
eighth 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

Hot gas application

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

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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. 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).

Defrost via data communication

Defrosting is started by the override function in a system man­ager, which also coordinates the defrosting stop.

Defrost on demand

1 Based on refrigeration time

When the aggregate refrigeration time has passed a xed 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

Max. 10

System manager

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.

External display

If an external display is connected to the controller, data commu­nication can also be connected, though this requires the installa­tion of a separate data communication module.

Extra data communication

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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 20 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

Hot gas defrost

This type of connection can be used on systems with hotgas
defrost, but only in small systems in, say, supermarkets – the
functional content has not been adapted to systems with large
charges. Relay 1’s change-over function can be used by the
bypass valve and/or the hot gas valve.
Relay 2 is used for refrigeration.

3

4

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Refrigeration control with two compressors

This group of applications can be used if the controller is to cut
two compressors in and out.
The functions can be compared with wiring diagrams 1 to 3, but
instead of controlling fans the relay is here used for compressor

2.

The two compressors must be of the same size. When the
controller demands refrigeration it will rst cut in the compres­sor with the shortest operating time. After the time delay the
second compressor will be cut in.

When the temperature has dropped to ”the middle of the dif­ferential”, the compressor with the longest operation time will be
cut out.
If the running compressor does not manage to reduce the tem­perature to the cutout point, the other compressor will be cut in
again. This happens when the temperature reaches the top part
of the dierential. If the temperature is instead ”stuck” in the dif­ferential for two hours, there will be a change-over between the
two compressors so that the operating time can be equalised.
The two compressors must be of a type that can start up against
a high pressure.

The compressors’s settings for ”Min On time” and ”Min O time”
will always have top priority during normal regulation. But if one
of the override functions is activated, the ”Min On time” will be
disregarded.

5

6

7

If the controller is to cut 2 compressor and 1 fan in and out, relay
4 must cut the fan in and out.
This function is activated in application 10.

Simple refrigeration with defrost

This application can be used where there is only regulation of
refrigeration and defrost.

Heating function

This application is the same as under 1, but a heating function
has been added which protects the unit against too low tem­perature. The defrost function’s heating element is here used for
heating.

10

8

9

This application is used where the temperature can go below
the set cutout temperature for the refrigeration. To ensure that
the temperature will not become too low the heating element is
activated x degrees below the reference value.
The S3 sensor must be mounted. It supplies the signal when
there is heating.

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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 r03.
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.

Set point limitation

The controller’s setting range for the set point 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 set point, the max. allowable reference value must
be lowered.

To avoid a too low setting of the set point, 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 set point 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.
(For application 9 and S3 sensor must be used)

Heating function

The function uses the defrost function’s heating element for raising the temperature.
The function enters into force a number of degrees (r36) below the actual reference
and cuts out again with a dierential of 2 degrees. Regulation is carried out with
100% signal from the S3 sensor. The fans will be operating when there is heating. The
fans and the heating function will stop if door function has been selected and the
door is opened.
Where this function is used an external safety cutout should also be installed, so that
superheating of the heating element cannot take place.
Remember to set D01 to electrical defrosting.

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 %

r36 HeatStartRel

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