Danfoss AK-CC55 Single Coil, AK-CC55 Single Coil UI User guide

User Guide

Case/room controller (EEV) Type AK-CC55 Single Coil and

AK-CC55 Single Coil UI

SW Ver. 1.7x

For refrigeration appliances and cold storage rooms.

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Introduction 6

Portfolio overview 7

Function overview 7

Connectivity 8

Data communication 8

AK-CC55 Single Coil and Single Coil UI 9

External display 9

Controller functionality 10

Functions 10

Injection control 10

Adaptive superheat control 10

Adaptive liquid control 11

Liquid injection by use of stepper valve 11

Oil recovery 11

Adaptive liquid control (option 1 and 2) 12

Fixed opening degree (option 3 and 4) 12

Safety 12

Temperature control 12

Food temperature sensor 13

Temperature monitoring 13

Thermostat bands 13

Night setback of thermostat value 13

Temperature sensor types 14

Appliance cleaning 15

Appliance shutdown 15

Defrost control 16

Electrical defrosting 16

Hot gas defrosting 16

Natural defrost 16

Start of defrost 17

Stop of defrost 17

Defrost sequence 17

Real-time clock 19

Coordinated defrost 19

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Adaptive defrosting 19

4 dierent adaptive defrost modes 19

Melt function 20

Control of two compressors (only with custom set-up) 20

Rail heat 21

Fan 22

Light function 23

Night blind 24

Humidity control 24

Heating function (only with custom set-up) 26

Digital inputs 26

Forced closing 27

Door contact 27

Display 27

Override 28

Applications 29

AK-CC55 connections and application options 30

Application set-ups and IO connections 31

Product identication 34

AK-CC55 Single Coil connections 35

Data communication 35

AKV info 35

External solid state relay for rail heat 35

AKS 32R info 36

Coordinated defrost via cable connections 36

External display AK-UI55 36

Connections 37

Replacing AK-CC 550 with AK-CC55 38

Operation 40

Operation via data communication 40

Direct operation 40

Operation via AK-UI55 Set 40

Parameter groups when operating via display 42

Get a good start 42

AK-UI55 display menu (SW ver. 1.7x) 44

Thermostat 44

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Alarm settings 44

Compressor 45

Defrost 45

Injection control 46

Fan control 46

Defrost schedule 46

Humidity control 47

Miscellaneous 47

Control 49

DO cong and manual 50

Service 51

Operation via AK-UI55 Bluetooth 53

AK-CC55 connect menu (SW ver. 1.7x) 54

Start / Stop 54

Conguration 54

Thermostat control 56

Alarm limits and delays 57

Humidity control 59

Injection control 59

Defrost control 60

Defrost schedules 62

Compressor 63

Fan control 63

Railheat control 64

Light/Blinds/Cleaning control 64

Display control 65

Alarm relay priorities 66

Miscellaneous 66

Advanced 67

Fault message 69

Operating status 71

Product specication 72

Technical data 72

Electrical specications 72

Sensor and measuring data 72

Input and output relay specications 72

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Function data 73

Environmental conditions 73

Dimensions 73

Ordering 74

Certicates, declarations, and approvals 75

Statements for the AK-UI55 Bluetooth display 75

Online support 77

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Introduction

Application

Complete refrigeration appliance control with great exibility to adapt to refrigeration appliances and cold storage rooms.

Advantages:

• Universal controller for several dierent refrigeration appliances

• Quick set-up with predened settings

• Easy conguration and service using a mobile app with Bluetooth

• Energy optimization of the whole refrigeration appliance

• Adaptive Minimum Stable Superheat (MSS) control is performed with lowest possible superheat

• Allows the suction pressure to be raised several degrees

• Adaptive Liquid Control (ALC) can be performed with superheat down to 0 degrees on transcritical CO2 systems with liquid ejectors

Principle

The temperature in the appliance is registered by one or two temperature sensors which are located in the air ow before the evaporator (S3) or after the evaporator (S4) respectively. A setting for thermostat, alarm thermostat and display reading determines the inuence the two sensor values should have for each individual function.

In addition, product sensor S6, which can be optionally placed in the appliance, can be used for registration and alarming of the temperature near the food items.

The temperature of the evaporator is registered with the S5 sensor which can be used as a defrosting sensor.

In addition to the output of the electronic AKV injection valve, the controller has relay outputs which are dened by the application setting.

Figure 1: AK-CC55 with evaporator, AKV valve and sensor positions

AK-CC55 Compact

AK-CC55 Single Coil

AK-CC55 Single Coil UI

AK-CC55 Multi Coil

Product image

Valve

1 x TXV or AKV

1 x AKV

3 x AKV

Digital Output3554

Digital input

1 (2)

3 (2)

Analogue Output1111

Analogue Input

5 (4)

6 (7)

Display

1 remote

2 remote

1 remote + 1 Integrated

2 remote

Comm. module

Modbus

Optional comm. module

LON module

Application

AK-CC55 Compact

AK-CC55 Single Coil

AK-CC55 Single Coil UI

AK-CC55 Multi Coil

AKV - application (electrically operated expansion valve)

xxx

0 – 10 V to control external stepper driver

TXV - application (thermostatic expansion valve + solenoid valve or compressor)

Remote hot gas - application

One valve, one evaporator, one refrigeration section

xxx

One valve, one evaporator, two refrigeration sections

One valve and two evaporators, two refrigeration sections

Two valves and two evaporators (same refrigeration section)

Three valves and three evaporators (same refrigeration section)

Custom conguration of relay outputs

Two compressorsxx

Heating functionxx

Control of air humidity

Adaptive superheat

xxx

Adaptive liquid control (zero superheat control for transcritical CO2 systems with liquid ejectors)

xxx

Adaptive defrosting

Product sensor

Oil recovery

RS485 Lon, option (AK-OB55)

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Portfolio overview

The AK-CC55 portfolio contains four controllers with dierent functionalities and application settings, as outlined in the table.

Table 1: AK-CC55 Portfolio

Function overview

Table 2: AK-CC55 function overview by type

Remote Display Service App

AKA 245: LON units only and max 250 controller parameters

System Manager

Display Bus

Modbus

LON/ TCP/IP (SNMP)

Modbus

LON/ TCP/IP (SNMP)

Bluetooth

AK-UI55 Bluetooth

AK-UI55 Set

AK-UI55 Info

Smart Device (iOS or Android)

AK-CC55 Connect

AK-CC55 Single Coil UI

AK-CC55 Multi Coil

AK-CC55 Compact

KoolProg

Case Controller

Danfoss

80G8333

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Connectivity

The diagram outlines the connectivity options presented by AK-CC55 for the design of system functionality.

Figure 2: Connectivity

Data communication

The controller has built-in MODBUS data communication. If there is a requirement for a dierent form of data communication, a Lon RS 485 module can be inserted in the controller.

The connection must then be to the module.

Figure 3: Mounting of communication module

Standard enclosure. Typically used for display cases where the controller is mounted in a tray.

Danfoss

84B8236

The standard enclosure can be expanded with one or two external displays.

Danfoss

84B8238

Enclosure with built-in setting display. Typically used for cold rooms.

Danfoss

84B8274

For controllers with built-in, only one external display can be connected.

Danfoss

84B8239

AK-CC55 Single Coil and AK-CC55 Single Coil UI

AK-CC55 Single Coil and Single Coil UI

AK-CC55 Single Coil – Controlling one EEV valve.

An application mode setting will congure inputs and outputs for the desired use. There are nine applications to choose from. Regulation is performed using an AKV expansion valve or an external stepper driver via Analogue Output A01.

AK-CC55 Single Coil UI

Single Coil controller with built-in display. Same functionalities as AK-CC55 Single Coil.

External display

There are three versions available with dierent functions:

• AK-UI55 Info: Temperature display.

• AK-UI55 Set: Temperature display with control buttons on the front.

• AK-UI55 Bluetooth: Temperature display with Bluetooth communication, for use with AK-CC55 Connect Mobile app.

Figure 4: AK-UI55 Info Figure 5: AK-UI55 Set Figure 6: AK-UI55 Bluetooth

Danfoss

84B2732

AKV

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Controller functionality

Functions

• Day/night thermostat with ON/OFF or modulating principle

• Product sensor S6 with separate alarm limits

• Switch between thermostat settings via digital input

• Adaptive control of superheat

• Adaptive liquid control

• Oil recovery (ushing oil back to condensing unit)

• Adaptive defrosting based on diagnostics

• Start of defrost via schedule, digital input, network or setting display

• Natural, electric or hot gas defrost

• Stop of defrost on time and/or temperature

• Coordination of defrosting among several controllers in a line-up

• Pulsing or ECO control of fans when thermostat is satised

• Appliance cleaning function for documentation of HACCP procedure

• Rail heat control via day/night load or dewpoint

• Humidity control in cold storage rooms

• Door function

• Control of two compressors

• Control of night blinds

• Light control

• Heat thermostat

• High accuracy inputs will guarantee a better measuring accuracy than stated in the standard EN ISO 23953-2 without subsequent calibration (Pt 1000 ohm sensor)

• Support of user-dened temp. sensor type

• Integrated MODBUS communication with the option of mounting a LonWorks communication card

Injection control

Adaptive superheat control

Liquid injection in the evaporator is controlled by an electronic injection valve of the type AKV. The valve operates as both expansion valve and solenoid valve. The controller opens and closes the valve based on sensor readings.

Figure 7: Adaptive superheat control with AKV valve

The superheat is measured via a pressure sensor Pe and temperature sensor S2. By using a pressure sensor, and temperature sensor a correct measurement of superheat is achieved under all conditions which ensures a very robust and precise control. The signal from one pressure transmitter can be shared by max. 10 controllers, but only if there is no signicant pressure dierence between the evaporators in question.

The function contains an adaptive algorithm which independently adjusts the valve’s opening so that the evaporator constantly supplies optimum amount of refrigerant.

EKF

0 – 10 V

ETSLLSV

Danfoss

84Z8230

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Adaptive liquid control

Adaptive liquid control is used in trans-critical CO2 ejector systems, which allow liquid ow. When adaptive liquid control is initiated, the superheat of the evaporator will be minimized so that a controlled amount of liquid is present at the outlet of the evaporator.

This type of control requires that the controller receives an on/o signal from (for example) a suction accumulator in the suction line.

Figure 8: Adaptive liquid control with AKV valve

A level switch in the tank will register when the liquid level exceeds the max. level. When this happens, the controller will switch to dry expansion, and then back to liquid control when the liquid level has dropped. The function is dened in setting o02, o37 or o84.

The function can also be activated via data communication from a system unit. If the adaptive liquid control signal is lost, the controller will automatically switch back to dry expansion.

 WARNING:

Accidental actuation may allow liquid throughput to the compressor. It is the installer’s responsibility to ensure that signal loss to the controller will not result in liquid throughput to the compressor. Danfoss accepts no responsibility for damage resulting from inadequate installation.

Liquid injection by use of stepper valve

Instead of AKV, an external stepper driver can be connected to AO1 (0 – 10 V) to drive a stepper valve. DO1 (AKV output) is then congured to close a liquid line solenoid valve (LLSV) when the stepper valve output is 0%. The LLSV is also closed at power failure.

Figure 9: Injection control via step motor valve and liquid line solenoid valve (LLSV)

Oil recovery

In some multi evaporator systems, oil might accumulate in the evaporators over time. The oil recovery feature will help to get the oil back to the compressors/suction accumulator.

Oil recovery can be initiated via a digital input signal or as a network signal. When oil recovery is initiated, the valve opening degree will be increased to ush the oil out of the evaporator.

Danfoss

84B8328

xyABCDE

Time

Temp%

AKV OD%

Superheat

SH ref

Adaptive liquid control forced cooling

Oil recovery

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Oil recovery has the following control options: 0 = No oil recovery 1 = Adaptive liquid control + Normal fan control 2 = Adaptive liquid control + Fan OFF 3 = Fixed opening degree of valve + Normal fan control 4 = Fixed opening degree of valve + Fan OFF

Adaptive liquid control (option 1 and 2)

When oil recovery is initiated, the injection function will switch to adaptive liquid control, decreasing the superheat reference, increasing the valve opening degree and thereby achieving a controlled amount of liquid refrigerant at the outlet of the evaporator. As the compressor controller at the same time runs with a higher capacity/speed, this combination will result in a higher amount of returned oil.

Figure 10: Adaptive liquid control increases valve opening degree during oil return

Fixed opening degree (option 3 and 4)

When oil recovery is initiated, the injection function will switch to a user-dened opening degree to ood the evaporator with refrigerant and thereby ush the oil back to the compressor/suction accumulator. However, this option provides no control or monitoring of the superheat and it is solely up to the user to ensure that the system design provides a safeguard of the compressors.

Safety

A couple of safety functions are in place to protect the preserved food from too low temperatures during an oil recovery cycle.

If an oil recovery has been ongoing for a longer period than the set “Max. oil recovery time”, oil recovery will be stopped, and normal control resumed.

Oil recovery is stopped if the alarm air temperature decreases below the set low alarm limit.

Temperature control

The temperature in the appliance is registered by one or two temperature sensors which are located in the return air before the evaporator (S3) or after the evaporator (S4) respectively. A setting for the thermostat, night thermostat, alarm thermostat and display reading determines how much the two sensor values should inuence each individual function, e.g. 50% of S4 will produce an equal value from both sensors.

The actual temperature control can take place in two ways:

As an ordinary ON/OFF regulation with a dierential, or

As a modulating control where the temperature variation will not be nearly as high as in ON/OFF control

ON/OFF control

Modulating control

AK-CC55 Single Coil and AK-CC55 Single Coil UI

There is, however, a limit to the use of a modulating control as it can only be used in remote cabinets. It is not recommended to use modulating thermostat control in low temperature applications. In applications with one evaporator and one compressor the thermostat function with ON/OFF control should be selected. In remote cabinets, the thermostat function may either be selected for ON/OFF control or modulating control.

Table 3: Control methods

Food temperature sensor

A separate optional product sensor S6, which may be placed in the appliance, can also be used and can register and monitor the food temperature in the appliance. There are separate alarm limits and time delays for the product sensor.

Temperature monitoring

Just as is possible for the thermostat, the alarm monitoring can be set with a weighting between S3 and S4 so that you can decide how much the two sensor values should inuence the alarm monitoring. Minimum and maximum limits can be set for alarm temperature and time delays. A longer time delay can be set for high temperature alarm. This time delay is active for pull-down after defrosting, appliance cleaning and start-up.

Thermostat bands

Thermostat bands can be used benecially for appliances where dierent product types are stored, which requires dierent temperature conditions. It is possible to change between the two dierent thermostat bands via a contact

signal on a digital input. Separate thermostat and alarm limits can be set for each thermostat band – also for the product sensor.

For the defrost control, separate defrost stop temperature and max. defrost time can be set for each thermostat band. For the compressor control it is possible to disable the second compressor in thermostat band 2 if required.

Figure 11: Thermostat band function with two dierent band settings

Night setback of thermostat value

In refrigeration appliances there may be big load dierences between the shop’s opening and closing hours, especially if night lids/blinds are used. The thermostat reference may be raised here without it having any eect on the product temperature.

Change-over between day and night operation can take place as follows:

AK-CC55 Single Coil and AK-CC55 Single Coil UI

• via an external switch connected to a digital input

• via a signal from the data communication system

Figure 12: Thermostat band function with Night setback

Temperature sensor types

The S2 and S6 sensors always have to be Pt1000 sensors due to the high measuring accuracy.

For the S3, S4 and S5 sensors, the user can select between the following sensor types: 0=Pt1000 (Danfoss AKS 11) 1=PTC1000 (Danfoss EKS 111) 2=NTC 5k (Danfoss EKS 211) 3=NTC 10k (Danfoss EKS 221) 4 = User-dened

If “User-dened” is selected, three sensor measuring points must be provided and based on these three sensor points, a sensor characteristic is generated.

A sensor point is dened by setting a temperature value and the corresponding resistance value at this temperature. The resistance value is set via two values for kohm and ohm respectively. These values can be found in the data sheet for the sensor.

The three sensor points must be:

Lowest temperature in wanted measuring range

Highest temperature value in wanted temperature range

Temp. value in the middle where a high measuring accuracy is required

A sensor error is detected at temperature values below/above the min./max. temperature values typed in for the sensor points.

350

300

250

200

150

100

-40 -20 0 20 40 60 80

Danfoss

80G8338

xyA

Temp [°C]

R [kohm]

Sensor point (-30 °C, 180 kΩ)

-++°C1÷+

Fan2÷÷O3++°C

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Figure 13: Example of sensor points from a NTC sensor

Limitations:

A user dened temperature sensor can only be be dened within the temperature range from -40 – +60 °C and within the resistance range from 400 – 179.999 ohm.

When applying a new user dened sensor type, please contact Danfoss for validation of compliance and measuring accuracy.

Appliance cleaning

This function makes it easy for the shop’s sta to carry out a cleaning of the appliance according to a standard procedure. Appliance cleaning is activated via a pulse signal – as a rule via a key switch placed on the appliance or via the AK-CC55 Connect mobile app.

Appliance cleaning is carried out via three phases:

At the rst activation, the refrigeration is stopped, but the fans keep on operating in order to defrost the evaporators. ”Fan” is shown on the display.

At the second activation, the fans are also stopped and the appliance can now be cleaned. ”OFF” is shown on the display.

At the third activation, refrigeration is recommenced. The display will show the actual appliance temperature, o97 setting.

When appliance cleaning is activated, a cleaning alarm is transmitted to the normal alarm recipient. A later processing of these alarms will document that the appliance has been cleaned as often as planned.

There are no temperature alarms during appliance cleaning.

Table 4: Appliance cleaning function

Appliance shutdown

The function closes the AKV valve and all outputs are switched o. The cooling appliance is stopped like the “Main switch”, but this happens without an “A45 standby alarm”. The function can be enabled by a switch on the DI input or via a setting through data communication.

Danfoss

84B8329

M M

ABC

Bypass valve

Suction valve

Hot gas valve

Danfoss

84B8330

M M

Danfoss

84B8331

M M

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Defrost control

Defrost method

The following defrost methods can be selected: 0: None 1: Electrical 2: Hot gas defrost (Simple) 3: Natural

Electrical defrosting

At electrical defrost, an electrical heater is placed in front of the evaporator and the fan will “pull” the hot air through the evaporator during defrosting.

Figure 14: Electrical defrosting

Hot gas defrosting

Remote hot gas defrost is supported in application mode 5. The hot gas defrost sequence covers control of the hot gas valve, suction valve and drain valve. It is intended for smaller systems in e.g. supermarkets – the functional content has not been adapted to industrial systems with large refrigerant charges.

Figure 15: Hot gas defrosting

Simple hot gas defrosting

If hot gas defrost is selected in application 1-3, the compressor will be running during defrost and a hot gas valve (HGV) is bypassing the compressor discharge gas to the evaporator inlet and thereby the evaporator is defrosted.

Natural defrost

At natural defrost, the ice is melted by running the fans and thereby circulating warm air through the evaporator.

Figure 16: Natural defrost

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Start of defrost

A defrost can be started in dierent ways:

Interval:

Defrost is started at xed time intervals like e.g. every eighth hour. An interval must ALWAYS be set to a "higher" value than the period set between two defrostings when a schedule or network signal is used.

Week schedule:

Here defrost can be started at xed times of the day and night. However, max. 6 defrosts per day.

Contact:

Defrost is started with a contact signal on a digital input.

Figure 17: Defrost start

Network:

The defrost start signal is received from a system manager via data communication.

Adaptive defrost:

Here defrosting is started based on intelligent registering of evaporator performance.

Max. thermostat runtime:

When the aggregate time has passed a preset value, a defrost will be initiated.

Manual:

An extra defrost can be activated from the defrost button on the AK-UI55 Set display (though, not with application

5) or via a parameter setting. All the mentioned methods can be used in parallel – if just one of them is activated, a

defrost will be started.

Stop of defrost

Defrosting can be stopped by either:

• Time

• S4A temperature (with time as safety)

• S5A temperature (with time as safety)

• S5A and S5B temperatures (with time as safety)

When the selected defrost stop sensor reaches the set defrost stop limit, the defrost is terminated. If the defrost stop sensor does not reach the set defrost stop limit within the set max. defrost time, the defrost will be terminated on time.

Minimum defrost time

When using hot gas for defrosting, the heat is coming from within the evaporator, and this means that the S5 sensor is rising fast when the inner layer of ice is melted. This will sometimes cause parts of the evaporator not to be defrosted when defrost is terminated on S5 evaporator temperature.

To prevent this, the user is given the option of setting a minimum defrost time. When a defrost is initiated, it will have to run for the set minimum time even if the set defrost stop limit has been reached by the selected defrost stop sensor.

Defrost sequence

When a defrost is initiated, the controller will run through the following sequence:

BA C D E

Danfoss

84B8332

AKV

xABCDETime

Pump down

Defrost

Hold

Drip

Fan delay

Danfoss

84B8333

A B C D E F G

AKV

xABCDEFGHIJ

Time

Pump down

Hot gas injection delay

Defrost

Hold

Drain

Drip

Fan delay

Hot gas valve

Drain

Suction

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Pump down: where the evaporator is emptied of refrigerant

Hot gas inj. delay (Hot gas only): where suction valve is given time for closing

Defrost: where the ice on the evaporator is melted

Hold after defrosting: where multiple controllers wait for each other (coordinated defrost)

Drip o: where remaining water is dripping o evaporator

Drain delay (Hot gas only): where the drain valve is opened to drain the liquid refrigerant

Fan delay: where the fans are restarted when the remaining water on the evaporator has turned into ice

Figure 18: Electrical defrost sequence

During an electrical defrost sequence where the defrost heater is ON during defrost, AKV valve is closed and fans are running during defrost but stopped during drip.

Figure 19: Remote hot gas defrost sequence

Remote hot gas defrost sequence where suction valve and drain valves are closed while hot gas valve is injecting hot gas into the evaporator. After defrost, the drain valve is opening to drain the evaporator for liquid refrigerant and then the suction valve is opening. When the water has dripped o the evaporator, liquid injection is started via the AKV valve and the fans start when the evaporator temperature has reached the fans' start temperature.

Fan control during defrost

During the defrost sequence, the evaporator fans can be controlled in one of the following ways:

The fan is OFF in the entire defrost sequence

The fan is ON during the entire defrost sequence except during fan delay state

The fan is ON during defrost state and is OFF in the rest of the defrost sequence

Like option 2, however the fans can be stopped if the selected defrost stop sensor exceeds a set fan stop limit

System manager

Max 10.

Danfoss

84B8268

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Real-time clock

The controller has a built-in real-time clock which can be used to start defrosts. This clock has a power reserve of four days.

If the controller is equipped with data communication, the clock will automatically be updated from a Danfoss system manager.

Coordinated defrost

There are two ways in which coordinated defrost can be arranged.

Figure 20: Coordinated defrost options

Either with wire connections between the controllers or via data communication:

Wire connections

The digital input DI2 must be congured for coordinated defrost and wiring must be connected between the relevant controllers. When one controller starts a defrost, 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.

Coordination via data communication

Here the system manager handles the coordination. The controllers are gathered in defrosting groups and the system manager ensures that defrosting is started in the group according to a weekly schedule.

When a controller has completed defrosting, it sends a message to the system manager and then goes into a waiting position. When every controller in the group is in a waiting position, refrigeration is again permitted in all the individual controllers.

Adaptive defrosting

The Danfoss adaptive defrost algorithm detects the amount of ice build-up and cancels a scheduled defrost if it is not needed, or it can be set up to only perform defrost if the evaporator air ow is getting interrupted by frost or ice.

The overall concept is based on comparison of the energy uptake on the refrigerant ow side with the energy emission on the air ow side. When the evaporator is clean, an energy balance is assumed, while a growing imbalance can be identied when ice formation is build up on the evaporator surface ending up with blocked

airow.

4 dierent adaptive defrost modes

0 O

1. Monitoring

Can be set up in parallel to other defrost methods and generate an alarm in case of blocked air ow / ice-up of the evaporator. If ash gas issues are detected on the refrigerant ow side, a ash gas alarm is generated.

AK-CC55 Single Coil and AK-CC55 Single Coil UI

2. Adaptive skip day:

Allows the controller to cancel (skip) defrosts scheduled within day time. Defrosts scheduled at night operation will be carried through and not skipped. Only defrosts that are set up via a schedule in the frontend using master control functions or set up via the internal defrost schedule in the controller can be skipped.

3. Adaptive skip day and night:

With this set-up, the controller can allow to cancel (skip) defrosts scheduled both within day time and within night time. For both adaptive skip day and night max. 3 consecutive defrosts can be skipped, whereafter the 4th scheduled defrost will be performed even if only little ice should be present.

4. Full adaptive:

Full Adaptive mode is ideal for applications where defrost is not requested to be performed at a certain time, but can be performed whenever ice is starting to interrupt the airow. It makes sense to combine this mode with the defrost interval timer as a safety timer.

Adaptive defrosting requires the following connections:

• Expansion valve type AKV

• Pe evaporator pressure and S2 gas out temperature

• Temperature signal from both S3 and S4. Sensors must be placed in the airow/channel immediately before / after the evaporator.

• Condensing temperature Tc is distributed via the network from the system manager. If Tc is not received by the case controller, the adaptive defrost function is using default back-up values.

 NOTE:

Adaptive parameters will be reset after a defrost has been initiated or at main switch in stopped or service mode. At start up with a warm evaporator (measured with S2 sensor), the evaporator is presumed clean. If the evaporator temperature is measured below 0.1 °C, adaptive defrost will request a defrost start to secure a clean evaporator.

Min. time between defrosts

There is a preset 2 hours minimum time between defrosts. This avoids that planned defrosts in accordance with the weekly schedule are carried out immediately after an adaptive defrost has been carried out. The time applies from when an adaptive defrost has been completed to when a planned defrost is again permitted. The adaptive defrost will not start defrosting with a shorter interval than the 2 hours either.

Melt function

This function will prevent the air ow in the evaporator from being reduced by frost created by uninterrupted operation for a long time.

The function is activated if the thermostat temperature has remained in the range between -5 °C and +10 °C for a longer period than the set melting interval. The refrigeration will then be stopped during the set melting period. The frost will be melted so that the air ow and hence the evaporator’s capacity will be greatly improved.

Control of two compressors (only with custom set-up)

Two compressor steps can be controlled cyclic or sequentially. At cyclic control, two compressors must be of the same size, while in sequential control compressor step 1 can be larger than step 2.

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Figure 21: Control of two compressors

Cyclic control

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 dierential”, the compressor with the longest operation time will be cut out.

The running compressor will continue until the temperature has reached the cut-out value. Then it will cut out. When the temperature again reaches the middle of the dierential, a compressor will again be started.

If one compressor cannot maintain the temperature within the dierential, the second compressor will also be started.

If one of the compressors has run on its own for two hours, the compressors will be changed over so that operational time is balanced.

The two compressors must be of a type that can start up against a high pressure.

The compressor'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, like e.g. defrost, door open function, case shutdown, forced closing, the ”Min. On time” will be disregarded.

Sequential control

Compressor steps are controlled in the same manner as described for cyclic control, but compressor step 1 will always be started rst and cut out as the last one. No time equalization is available in sequential control mode.

Rail heat

It is possible to pulse-control the power to the rail heat in order to save energy. Pulse control can either be controlled according to day/night load or dew point.

Relay or analogue output

A relay output can be used when long cycle times are permitted. If fast pulsing is required, the AO1/PWM output can be used. The output must be connected to an external power solid state relay. The cycle time must be congured for the relay output in o43 or for analogue output in P82.

Pulse control according to day and night

Various ON periods can be set for day and night operation. A cycle time is set as well as the percentage part of the period in which the rail heat is ON.

Danfoss

84B2729

o88

o86

100%

o87

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Figure 22: Rail heat control, day/night load

Pulse control according to dewpoint

In order to use this function, a system manager of the type AK-SM is required which can measure ambient temperature and humidity to calculate dew point and distribute to the appliance controllers. For this the rail heat’s ON period is controlled according to the distributed dewpoint.

Two dew point values are set in the appliance control:

• One where the eect must be max. i.e. 100%. (o87)

• One where the eect must be min. (o86)

At a dewpoint which is equal to or lower than the value in 086, the eect will be the value indicated in o88. In the area between the two dew point values, the controller will manage the power to be supplied to the rail heat.

Figure 23: Rail heat control, dew point

During defrosting

During defrosting rail heat will be active, as selected in setting d27.

Fan

Pulse control

To obtain energy savings, it is possible to pulse control the power supply to the evaporator fans. Pulse control can be accomplished in one of the following ways:

• during the thermostat’s cut-out period (cold room)

• during night operation and during the thermostat’s cut-out period (appliance with night blinds) (The function is not actual when r14=2, i.e. modulating regulation).

A period of time is set as well as the percentage of this period of time where the fans have to be operating.

100%

50%

Danfoss

84B8318

XYABTime

Fan speed

Fan

Fan ECO

AK-CC55 Single Coil and AK-CC55 Single Coil UI

Figure 24: Fan cycle time

Cut-out of fans during plant breakdowns

If the refrigeration in a breakdown situation stops, the temperature in the cold room may rise quickly as a result of the emission of heat from large fans. In order to prevent this situation, the controller can stop the fans if the temperature at S5 exceeds a set limit value. The fans will start running again when the S5 temperature has dropped 2K below the set limit. (The function can also be used as a type of MOP function. Here the load on the compressors is limited until the S5 temperature has fallen below the congured value).

Fan ECO operation (only custom set-up)

Fan ECO operation is used to reduce fan speed during night operation – typically on cabinets with night blinds.

The function is enabled when a relay has been congured for Fan ECO function in one of the applications with custom set-up of relay functions.

The fan economy control (fan speed) is controlled via the two fan outputs:

• Fan output

• Fan Eco output

If the Fan output is activated, then the fan is running with 100% speed. If the Fan ECO output is also activated, then the fan is running with reduced speed (typically 50%). If both fan outputs are de-activated, then the fans are stopped.

Figure 25: Fan ECO control – Fan speed reduced to 50% during night operation

The fans will always run with full speed during day operation, rst stage of case cleaning, defrost, forced cooling and when air heating is active.

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 blind.

The light function can be dened in several ways:

AK-CC55 Single Coil and AK-CC55 Single Coil UI

The light is controlled via the day/night function. A digital input setup for light control can switch light ON, if the light is switched o during night

The light is controlled by a system manager via the parameter o39. A digital input setup for light control can switch light ON, if the light is switched o by the system manager.

Light is controlled via the door switch. Light is switched ON when door is opened and switched OFF 2 minutes after the door has been closed.

Like option 2, but here the light is switched ON automatically if the communication to the system manager has been lost for 15 minutes

Light is only controlled via a digital input setup for light control

The light load must be connected to the NC terminals on the relay. This ensures that the light remains ON in the appliance if power to the controller should fail.

A setting denes how light is controlled when regulation is stopped via r12 Main switch = OFF (see o98). The light is switched o when the appliance cleaning function is activated.

Night blind

Motorised night blinds can be controlled automatically from the controller either through the custom set-up night blind output or via the NO connector on the light relay. The night blinds will follow the status of the light function. When the light is switched on, the night blinds open, and when the light is switched o, 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 pulse signal is activated, the night blinds will open and the refrigeration appliance can be lled with new products. If the pulse signal is activated again, the blinds close.

When the night blind function is used, the thermostat function can control with dierent weighting between the S3 and S4 sensors. A weighting during day operation and another when the blind is closed.

A night blind is opened when the appliance cleaning function is activated.

A setting can dene that the night blind is opened when "r12" (Main switch) is set to o (see o98).

When the night blind rolls down, the fan will be stopped for the set time. The night blind can thereby roll down to the correct position.

Humidity control

In application 8 when setup for room control it is possible to dene if humidity control should be done via a humidier or a dehumidier.

When humidity control is enabled, the second display will read out the actual humidity.

The controller measures the humidity via a 0 – 10 V signal from a humidity sensor and by means of a DO relay it can activate a humidier or a de-humidier.

High and low humidity alarm limits can be set to generate a humidity alarm.

Humidity control is disabled when main switch is OFF, at manual control, at case shutdown, at forced closing mode, at door open, if cooling is stopped, at humidity sensor error and at case cleaning.

It is possible to dene whether humidity control is enabled during defrost or not.

+ 53 hidden pages

Danfoss AK-CC55 Single Coil, AK-CC55 Single Coil UI User guide

Contents

Introduction

Portfolio overview

Function overview

Connectivity

Data communication

AK-CC55 Single Coil and Single Coil UI

External display

Controller functionality

Functions

Injection control

Adaptive superheat control

Adaptive liquid control

Liquid injection by use of stepper valve

Oil recovery

Adaptive liquid control (option 1 and 2)

Fixed opening degree (option 3 and 4)

Safety

Temperature control

Food temperature sensor

Temperature monitoring

Thermostat bands

Night setback of thermostat value

Temperature sensor types

Appliance cleaning

Appliance shutdown

Defrost control

Electrical defrosting

Hot gas defrosting

Natural defrost

Start of defrost

Stop of defrost

Defrost sequence

Real-time clock

Coordinated defrost

Adaptive defrosting

Melt function

Control of two compressors (only with custom set-up)

Rail heat

Light function

Night blind

Humidity control