Installation
and service
RI.8A.B1.02 ® RI.8A.B2.02 09-2001
Controller for cold room
Type AKC 72A
Software Version 1.2x
2
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
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AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001
Principle
AKV /
AKVA
4
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.
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AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001
Installation
Assembly
6
Connections
Relays for terminals 5 to 12:
AC-1: 3 A (ohmic)
AC-15: 2 A (inductive)
or
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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.
8
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
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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).
10
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.
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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
12
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.
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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
14
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.
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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
16
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)
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AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001
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.
18
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.
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AKC 72A Installation and service RI.8A.B2.02 © Danfoss 09/2001
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.
20
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.
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