Danfoss Controller for cold rooms. Type AKC 72AVers. 1.2x Installation guide

Brand: Danfoss

Model: Controller for cold rooms. Type AKC 72AVers. 1.2x

Type: Installation guide

Installation

and service

RI.8A.B1.02 ® RI.8A.B2.02 09-2001

Controller for cold room

Type AKC 72A

Software Version 1.2x

Contents

Principle ...................... 3

Operation .................... 4

Installation .................. 5

Assembly ............................................ 5

Connections ........................................ 6

Start-up ....................... 8

1. Get a good start ...............................8

2. Defrost and the controller’s ad-

dress ............................................ 11

3. System adjustment ....................... 13

4. Selection of additional functions .. 17

a. Limitation of the thermostat’s

setting range ............................ 17

b. Weighting of thermostat sensor 17

c. Thermostat type ........................ 18

d. Night setback ............................ 18

e. Defrost ...................................... 19

f. Fan operation ............................ 20

g. Log settings .............................. 22

h. Setting of superheat

and MOP ................................. 22

i. Compressor control .................. 23

j. Calibration of sensors .............. 24

k. Delay of output signals during

start-up ..................................... 25

l. Display settings and network

frequency ................................. 25

5. Control ......................................... 26

Daily operation......... 27

Trouble-shooting ..... 31

Control of outputs ... 36

Appendix

1. Data communication .................... 38

2. Battery .......................................... 41

Menu survey ............ 42

AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001

Principle

AKV /

AKVA

Operation

Here you obtain a quick

and clear view of the

system’s operating

conditions.

The alarm lamp flashes

when an alarm condition

arises.

When there is an alarm,

use this key for finding the

reason for it.

The green lamp lights up when:

-there is refrigeration

-there is defrost

-there is night operation

-the injection valve opens

Use the setup key for setting

the controller’s functions.

Use the arrow keys for

moving about in the

controller’s menu.

Use the plus and minus keys

for changing settings in the

controller’s menu.

The manual key allows you

to start and stop the

regulation. You may also

force-operate the

controller’s outputs via this

key.

When important settings

are changed, regulation

must be stopped to allow

setting to be made.

The graphic display

provides you with clear

information about the

controller’s settings and the

system’s operating

conditions.

With this key you can

change the refrigerating

system’s cutin and cutout

temperatures.

Here you follow the

development of a selected

temperature.

With this key you can start

manual defrost and

establish the week’s defrost

programme.

Examples

As soon as the new value is

shown in the display it is

active.

Shows a position in the menu.

AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001

Installation

Assembly

Connections

Relays for terminals 5 to 12:

AC-1: 3 A (ohmic)

AC-15: 2 A (inductive)

AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001

13, 14 Data comunication

Only used in controllers that are provided with data

communication. Either DANBUSS or a printer can be

connected.

Cf. also appendix 1, page 38.

15, 18 Door (DI) ON/OFF

Signal input from switch function to stop refrigeration. The

signal may be a door switch and/or the compressor’s safety

controls.

There is no refrigeration when the connection between 15 and

18 is interrupted.

16, 17, 18 AKS 32R

Pressure transmitter for measuring the evaporating pressure.

Type: AKS 32R, -1 to 12 bar.

A pressure transmitter can transmit signals to five AKC

controllers. The pressure transmitter must

not

be grounded.

19, 20

S2 (PT1000)

Temperature sensor for measuring the gas temperature at

the evaporator outlet.

20, 21

Air on (PT1000)

Temperature sensor for measuring the hot air for the

evaporator.

22, 23

Air off (PT1000)

Temperature sensor for measuring the cold air leaving the

evaporator.

23, 24

Sdef (PT1000)

Defrost sensor for measuring the evaporator temperature.

1, 2

Mains connection 230 V a.c.

3, 4

The AKV or AKVA valve is connected here.

5, 6

Relay switch that can be used for controlling the light or the

compressor.

7, 8

Relay switch that can be used for controlling the fan.

9, 10

Relay switch that can be used for controlling the defrost.

11, 12

Relay switch that can be used for the alarm.

The relay switch is open:

- when the supply voltage to the controller is cut off

- when there is an alarm during normal operation

Warning!

If the compressor cuts out on the safety controls, the 15-18

connection must also be interrupted. In this way it is avoided

that the AKV valve continues the injection into the evaporator.

With this function you set the controller at its first start-up.

1. Get a good start

Via seven steps you make a rough setting of the refrigerating system, and when you

have gone through these seven steps the controller is ready for operation and

refrigeration based on the rough settings will have started.

Press the setup key to start.

Press the arrow-right key to proceed to the first setting.

1a. Select one of the languages offered.

Press the arrow-right key to proceed to the next menu block.

1b. Set date and time.

Use the plus and minus keys for setting the date and time.

Press the arrow-right key to proceed to the next menu block.

Start-up

AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001

1c. Select symbol of the application to be regulated.

You may choose between symbols for four different types of system.

They are: cold room, case, delicatessen and refrigerated multidecks.

You will refind the selected symbol in other menu displays when the controller has

been set. In this way it is easy to see where the measured values are found in the

actual refrigerating system.

Press the arrow-right key to proceed to the next menu block.

1d. Select temperature range and defrost type.

a) You may choose between two standard temperature ranges:

-High (thermostat range = refrigeration)

-Low (thermostat range = freezing)

b) Select defrost type

You may choose between electric or static defrost (static = fan operation only)

c) Select valve type used in the system: that is to say, electric expansion valve

AKV(A) 10, 15, 20 or thermostatic expansion valve, TEV

d) Select refrigerant

With the plus or minus key you can leaf through a list of possible refrigerants

Press the arrow-right key to proceed to the next menu block.

1e. Digital output 5,6

What is the digital output used for?

· If the compressor is selected, the digital output cuts in when the thermostat’s

cutin value is reached

· If light is selected, the digital output cuts in when the day/night function changes

to day operation or when DI is opened (door function).

Press the arrow-right key to proceed to the next menu block.

These three menus can only be set when regulation has

stopped (Standby in Manual 1).

1f. Access code and start of regulation

a) Select an access code.

If you select code 000, the code function will be cancelled, and there will be direct

access to all menus.

If you however select another value, you may prevent access via the manual key

and the setup key. (The daily user of the controller will then have access to all

functions, except those found behind the two keys).

b) Press the arrow-right key to start regulation.

If the other conditions in the system permit it, the controller will start refrigeration.

The regulation will however be based on “rough settings”, but these will be

corrected in section 3:

Proceed to section 2.

AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001

2a. Start of defrost

You can define up to six defrost cycles per weekday.

Press the defrost key twice.

(The menu block “Defrost 1” is explained in the “defrost” section on page 19).

In the menu block “Defrost 2” you will see seven horizontal lines. They represent the

weekdays with Monday being the top line.

On the illustration to the left you can also see some vertical lines on each weekday.

Each of these represents a defrost start. The time is shown on the axis below.

The menu display shows, e.g., “Monday 00:30”

When you keep the arrow-right key depressed, the cursor will move to the right

along the Monday line. At the same time the time (hour) will change.

- With the arrow-right or left key move the cursor to the start time of the defrost you

wish to perform

- Press the plus key to insert a marking at the time chosen

- Repeat this for all defrost starts on Monday (max. six)

- Press the arrow-down key and proceed with the next weekday

If you regret a defrost start you can cancel it with the minus key when the cursor is

placed on top of the marking.

When you have gone through all the weekdays and the defrost times are in place,

you may leave the menu display by pressing the temperature key.

2. Defrost and the controller’s address

Cursor

2b. Unit address

(for controllers with DANBUSS data communication only)

Press the setup key.

With the arrow-down key move the cursor to “Network/other” (eight pushes).

Press the arrow-right key.

Set the controller’s Danbuss address (between 0 and 120) by means of the plus

or minus key. (If a printer is connected to the controller, address 124 must be

retained).

In addition to setting, this menu block can also be used for reading the controller’s

network address, the address of the alarm receiver and the gateway address.

For further details, refer to a gateway manual.

Proceed to section 3.

AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001

3. System adjustment

The settings will of course not match the system completely, so under the next

points the most important ones will be corrected.

If there are other settings than the subsequent ones that you wish to correct, please

refer to the controller’s menu blocks on page 43.

In this section you carry out a few adjustments of the factory settings with which the

controller started, cf. section 1.

Based on your own choice you will have one of the following factory settings:

Thermostat

Difference ....................... 2

SetpointLimit max ......... 50

SetpointLimit min ........ -50

Thermostat mode ON/OFF

Night offset ...................... 0

Monday day ............. 06:00

Monday night ........... 18:00

Alarm thermostat

Pulldown delay ........... 120

High Alarm delay .......... 30

Low Alarm delay ........... 30

Injection control

Superheat max. K ......... 12

Superheat min. K ............ 3

MOP control .............. OFF

MOP temperature ........... 0

Defrost control

Demand defrost ........ OFF

Stop method ............ Temp

Max defrost time ........... 45

Stop temperature ............ 8

Drain down ...................... 5

FanStart Temp/time . Temp

Max fan delay ............... 10

Alarm destinations

RFG not selected ............ 2

RFG changed ................. 2

Overfloat evap. ............... 0

Air temp. Alarms ............. 1

Def. per. exceeded ......... 2

Fan del exceeded ........... 2

AKS 32R error ................ 1

S2 errror ......................... 1

Air on error ...................... 1

Air off error ...................... 1

S Def error ...................... 1

Door alarm ...................... 1

Compressor

Pumpdown control ..... OFF

LP Cutout, bar ............... 0,5

LP Difference, bar ............ 2

LP Start delay ................... 0

Min. restart m. ................. 0

Configuration

Fan on period % ........... 100

Fan pulse period ............ 10

Fan stop on Sdef ........ OFF

Fan stop temp. .............. -10

DI alarm delay ................. 0

Light control ................... DI

Light off delay .................. 0

Delays outputs ................. 0

Log interval .................... 15

Log temp. .... Thermostat air

Setting High temperature High temperature Low temperature

+ static defrost + elec. defrost + elec. defrost

Thermostat

Cutout temp. ......................... 3 ................................... 3 .................................. -21

Air on % ................................ 0 ................................... 0 .................................. 100

Alarm thermostat

High alarm limit ..................... 10 ................................. 10 ................................ -15

Low alarm limit ...................... -3 .................................. -3 ................................. -30

Defrost control

Fan operation ....................... ON ............................... OFF ............................. OFF

Fan start temp. ..................... -3 .................................. -3 ................................. -10

Configuration

Fan when DI open ................ ON ............................... ON ............................... OFF

General factory settings Application-based factory selections

3a. Thermostat settings

Press the thermostat key once.

In the menu display “Setpoint” you can change the cutout value by means of the

plus or minus key. From the bottom line it will appear how the value changes within

the permitted range.

When the cutout value is changed, the cutin value will change correspondingly.

Now press the arrow-left or up key to move the cursor to the differential. It may

likewise be changed by means of the plus or minus key.

As soon as you change a value, it becomes active.

3b. Alarm thermostat settings

Press the setup key once and move the cursor down to “Thermostat”.

Now press the arrow-right key twice to enter the menu block for “High alarm”.

Here you can change the upper alarm limit (max. temperature), the time delay for

the alarm report at ordinary operation, and the time delay during a cooling-down

process (cf. the example on the next page).

Now press the arrow-right key once to enter the menu block for “Low alarm”.

Here you can change the lower alarm limit (minimum temperature) and the time

delay for the alarm report.

As soon as the mentioned alarm limits are changed, they become active.

AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001

Example:

There is the following interaction between time delays and alarms:

High alarm:

Delay: Time delay during normal operation.

Pulldown: Time delay enters into effect after activation of the ON input during

defrost or after a power failure. The time delay remains active until the actual air

temperature has fallen below the upper alarm limit.

Low alarm:

Delay: Alarm is given after the time delay (the valve closes when the alarm limit is

exceeded).

Curve 1: Cooling-down phase

(1): “Pulldown” time delay has been exceeded. The alarm is activated.

Curve 2: Normal regulation where the temperature becomes too high.

(2): “High delay” time delay has been exceeded. The alarm is activated.

Curve 3: Temperature becomes too low.

(3): “Low delay” time delay has been exceeded. The alarm is activated.

IN: Thermostat’s cutin value

OUT: Thermostat’s cutout value

Lim: Alarm limit for high

temperature and low

temperature

S: Alarm ceases

3c. Where is the alarm to be transmitted?

The controller can send alarm reports to various places.

This option is however dependent on whether the controller is provided with

DANBUSS data communication or not.

Press the setup key.

With the arrow-down key move the cursor down to “Alarm handling”

(seven pushes).

Press the arrow-right key.

(If you press the plus key in this menu you can cancel the list of alarms received).

Press the arrow-right key:

In four menu blocks you now have to define to whom each individual alarm

message is to be transmitted. With the plus or minus key set a value between 0 and

3 opposite the alarm text. The set value will determine where the alarm message is

to be sent:

Value AKC 72A without DANBUSS AKC 72A with DANBUSS

0 Nowhere Nowhere

1 Controller’s alarm output * Controller’s alarm output

and alarm log * DANBUSS as status 1alarm

(high priority)

2 Alarm log * DANBUSS

as status 2 alarm

(low priority)

3 Controller’s alarm output * Controller’s alarm output

and alarm log * DANBUSS as status 2

alarm (low priority)

4. Selection of additional functions

The controller contains a number of basic functions regulating the refrigeration and

adapted to the individual refrigerating system. Beyond that, the controller has a wide

selection of additional functions the purpose of which is to optimize and control the

regulation. A description is given below of how you can use these functions in the

best possible way.

4a. Limitation of the thermostat’s setting range

The thermostat can be set between -50°C and +50°C. But in many cases it may be

necessary to limit the control facilities for daily use - for example to avoid frost

damage to refrigerated products in case of unskilled operation.

Press the setup key and move the cursor down to “Thermostat”.

Press the arrow-right key to proceed to the next menu block.

Set the min. and max. values within which the thermostat can be set.

4b. Weighting of thermostat sensor

Here you can define the air temperature on the basis of which the thermostat is

to regulate.

Press the setup key.

Move the cursor down to “Thermostat” and press the arrow-right key five times.

With the plus and minus keys you can set the “Air on” sensor’s weighting:

100% = thermostat cuts out based on the temperature in the refrigerator’s air inlet

(Air on)

0%= thermostat cuts out based on the temperature in the refrigerator’s air

outlet (Air off).

If you require a combination of the two measurements, indicate a value between 0%

and 100%.

Example: Air on measures -20°C and Air off measures -25°C.

If the weighting is set at 60% you obtain a weighted thermostat temperature of:

60% x -20°C + 40% x -25°C = -22°C.

4c. Thermostat type

You may choose between two thermostat types -

- On/off thermostat:

a) Refrigeration stops when the temperature has reached the min. thermostat

value.

b) Refrigeration starts when the temperature has risen to the max. thermostat

value.

- Modulating thermostat:

The controller maintains a constant air temperature corresponding to the

mean value of the min. and max. thermostat value.

Press the setup key.

Move the cursor down to “Thermostat” and press the arrow-right key six times.

Select the thermostat type you want to use in the refrigerating system.

4d. Night setback

In some systems the heat load is reduced during the night. In such cases you

can increase the thermostat’s temperature limits to save energy.

Press the setup key.

Move the cursor down to “Thermostat” and press the arrow-right key twice.

With the plus key set the value by which the thermostat’s cutin and cutout values

are to be increased.

NB. If the night setback value is positive, the alarm limit for high temperature at

night operation will be increased correspondingly. If the value is negative, the alarm

limit for high temperature remains unchanged.

Now move the cursor down to “Day/night clock” and press the arrow-right key once.

In this and the following three menu blocks you can define the hours for day and

night operation for each of the seven days of the week. Set the individual hours with

the plus and minus keys.

NB. If the digital output is defined as a light switch, it will be interrupted during night

operation.

4e. Defrost

Here you may choose between ordinary defrost or defrost on demand which saves

energy. The defrost on demand function determines whether a planned defrost is to

be carried out, or whether it can be skipped.

The controller gathers internal regulating values which are analysed after each

planned defrost start. The analysis will produce the result that defrost is started or

that it is skipped. At the next planned defrost the analysis is repeated.

Press the setup key.

Move the cursor down to “Defrost” and press the arrow-right key.

Select whether defrost on demand is to be ON or OFF.

Further down in the display you can read the number of accomplished defrosts. If

you select defrost on demand, it will later appear how many of the planned defrosts

the controller has skipped, and how many it has accomplished.

Press the arrow-right key to proceed to the next menu block.

Select in which of the following ways defrost is to be stopped:

“temp”: Defrost stops when the defrost sensor has reached a certain

temperature. Set the required stop temperature.

“time”: Defrost stops when the set time has elapsed.

The following setting must be made, whether you select “temp” or “time”. (The time

setting is also used for stopping the defrost, if there should be an error on the

defrost sensor).

Set “Max.def.time” to the max. duration of a defrost period. If this period is

exceeded during a defrost, the alarm will sound. This alarm is reset automatically

after five minutes.

Set “Fan operation” in pos. ON, if the fans are to operate during the defrost.

If “Fan operation” is set in pos. OFF, press the arrow-right key to proceed to the

next menu block.

Here you can choose how the fans are to start when a defrost cycle is concluded.

There are two possibilities:

Based on temperature: Set “Fan start” to “temp” and “Fan start temp” to the

temperature required for the defrost sensor to start the fans.

Based on time: Set “Fan start” to “time”. Now set “Max. fan delay” to the period by

which the fan start is to be delayed when defrost has stopped. This

time must always be set, as it is also used as a safety function.

It is also possible with the controller to delay the start of the injection and the cutin

of the compressor. It allows drops of water to fall from the refrigerated surface, so

that it will not freeze up again so fast. If you have selected delayed fan start after

an accomplished defrost cycle, the time delay will start upon expiry of the drain-

down period.

Set the time delay “Drain down” at the value between 0 and 60 minutes which you

consider appropriate. You may later adjust this value, if required.

4f. Fan operation

When the thermostat has stopped refrigeration, the fans only need to run part of the

time. By pulse-feeding the effect to the fans in this way, energy is saved, and the

product quality is at the same time enhanced.

(The function is only active during the

thermostat’s cutout period).

Press the setup key.

Move the cursor down to “Fan control” and press the arrow-right key.

First select the time interval between fan start-ups.

Page is loading ...

Danfoss Controller for cold rooms. Type AKC 72AVers. 1.2x Installation guide

Danfoss Controller for cold rooms. Type AKC 72AVers. 1.2x Installation guide

Danfoss Controller for cold rooms. Type AKC 72AVers. 1.2x Installation guide

Related papers

Other documents