Danfoss AK-PC 530 Capacity Controller

Introduction

Application

The controller is used for capacity regulation of compressors or condensers in small refrigerating systems. Numbers of compressors and condensers can be connected, as required. There are eight outputs and more can be added via an external relay module.

Advantages

• Patented neutral zone regulation
• Many possible combinations for compressor constellations
• Sequential or cyclic operation
• Possibility of suction pressure optimisation via the data communication

Regulation

Regulation is based on signals from one pressure transmitter for the compressor regulation and one pressure transmitter for the condenser regulation plus one temperature sensor for the air temperature before the condenser. The two pressure transmitters can be replaced by two temperature sensors when regulation has to be carried out on brine systems.

• Pressure regulation P0 (pack)
• Temperature regulation Sx (chiller)
• Pressure regulation Pc (pack / chiller)
• Pressure regulation with variable reference (Sc3)

Functions

• Relays for compressor and condenser regulation
• Voltage output for capacity regulation of condenser
• Status inputs. An interrupted signal indicates that the safety circuit has been activated and the respective circuit stopped
• Contact inputs for indication of alarms
• Contact inputs for displacement of references or for indication of alarms
• Alarm relay
• External start/stop of regulation
• Possibility of data communication

Operation

All operation takes place either via data communication or via connection of a display type EKA 164 or EKA 165.

Combinations

The controller has ten relay outputs, two of which have been reserved for the alarm function and for the "VLT start/stop" function. For a start, relays are reserved for compressor capacities starting from DO1, DO2, etc. The remaining relays up to and including DO8 will then be available for fans. If more are required, one or more relay modules type EKC 331 with max. eight steps can be connected. The signals to these modules are to be taken from the controller's analog output. Another solution could be that the fan speed is controlled via the analog output and a frequency converter.

If the alarm function and the "AKD start/stop" function are left out, all ten relay outputs may be used for compressors and fans (but max. eight for compressors and max. eight fans).

Function Details

Capacity regulation

The cut-in capacity is controlled by signals from the connected pressure transmitter/temperature sensor and the set reference. Outside the reference, a neutral zone is set where the capacity will neither be cut in nor out. Outside the neutral zone (in the hatched areas named +zone and -zone) the capacity will be cut in or out if the regulation registers a change of pressure "away" from the neutral zone. Cut-in and cut-out will take place with the set time delays. If the pressure however "approaches" the neutral zone, the controller will make no changes of the cut-in capacity. If regulation takes place outside the hatched area (named ++zone and --zone), changes of the cut-in capacity will occur somewhat faster than if it were in the hatched area. Cut-in of steps can be defined for either sequential, cyclic, binary or "mix & match" operation.

Sequential (first in - last out)

The relays are cut in sequentially – first relay number 1, then 2, etc. Cut-out takes place in the opposite sequence, i.e. the last cut-in relay will be cut out first.

Cyclic (first in - first out)

The relays are coupled so that the operating time of the individual relays becomes equalised. At each cut-in, the regulation scans the individual relays' timer, cutting in the relay with the least time on it. At each cut-out, a similar thing happens. Here, the relay that has most hours on the timer is cut out.

Rx = random relay, h = number of hours

If capacity regulation is carried out on two compressors with one unloader each, the following function can be used: Relays 1 and 3 are connected to the compressor motor. Relays 2 and 4 are connected to the unloaders. Relays 1 and 3 will operate in such a way that the operating time for the two relays will become equalised.

C = compressor, L = Unloader

Survey of Functions

The total function content is shown below – not all functions are present at the same time. The setting of o61 determines which functions are present. The menu overview on page 14 shows the various functions and settings.

Condenser and Capacity Parameters

Mix and Match and Manual Control

Mix and Match step 1.

This function cuts the relay in and out depending on the definitions in "c17" to "c28". ("c17" to "c28" only used, if "o61" selected to "3" or "4"). (In Mix and Match couplings the settings "c08" and c09" are not used).

Step 1

Here in c17 set the relays to be ON at step 1. Setting takes place with a numerical value representing the combination of relays. See the survey page 11. Proceed by defining steps two, three, etc. The definition ends at the first c18 - c28 which is set to "0". The time delays "c01" and "c07" belong to the individual relay outputs. If a relay output is captured by the time delay, a changeover from one step to another will only take place when all the relay outputs concerned have been released. The time delay will not interfere with a relay which is ON in two successive couplings. If a compressor drops out there will be an alarm. The regulation will continue as emergency operation, as if the compressor were present.

Step 2.

Here you also set a value between 1 and 15. Here in c18 the value will indicate which relays have to be ON at step 2.

Step 3. etc.

4. Etc.

5.

6.

7.

8.

9.

10.

11.

12.

Manual control of compressor capacity

c31 CmpManCap%

This sets the capacity that is to be cut in when switching to manual control. (c01 and c07 will still apply)

Manual control

c32 CmpManCap

Manual control of the compressor capacity is enabled here. When set to ON, the capacity that is set in "c31" is cut in.

Condenser Capacity and Regulation

Definition of condenser and number of fans

c29 Fan mode

Here you set the number of fan steps with which regulation has to be carried out (but max. eight).

1-8: All fans are cut in and out with relays. The first vacant relay number is assigned to fan 1, the next to number 2, etc. Steps after DO8 must be executed through connection of a relay module type EKC 331 to the analog output. Cf. drawing on page 12.

9: All fans controlled via the analog output and a frequency converter.

10: Not used

11-18: Total number of fan relays (as 1-8), but here the starting sequence is altered after each time all fans are stopped.

Read temperature at sensor Sc3

u44 Sc3 temp

Read temperature at sensor Sc4

u45 Sc4 temp

(sensor is only used for monitoring)

Regulation parameters for the condenser regulation

Proportional band Xp (P = 100/Xp)

n04 Xp K

If the Xp value is increased, the regulation becomes steadier

I: Integration time Tn

n05 Tn s

If the Tn value is increased, the regulation becomes steadier

Manual control of condenser capacity

n52 FanManCap%

This sets the capacity that is to be cut in when switching to manual control.

Manual control

n53 FanManCap

Manual control of the condenser capacity is enabled here. When set to ON, the capacity that is specified in "n52" is cut in.

Speed control start value

n54 StartSpeed

Speed control will only be activated when the capacity requirement reaches this value.

Speed control stop value

n55 MinSpeed

Speed control will be stopped when the capacity requirement falls below this value.

Alarm Settings

The controller can give alarm in different situations. When there is an alarm the light-emitting diodes (LED) will flash on the display and the alarm relay will cut in. (In AK-PC 530 the alarm relay may be used for a fan, if required).

P0 min. (Alarm and safety function, see also page 20.)

A11 Min. P0. b

Here you set when the alarm at too low suction pressure is to enter into effect. The value is set as an absolute value.

Alarm delay P0 alarm

A44 P0AlrmDelay

The time delay is set in minutes. At min. setting the alarm is cancelled.

Pc max. (Alarm and safety function, see also page 20.)

A30 Max. Pc. b

Here you set when the alarm at too high condensing pressure is to enter into effect. The value is set as an absolute value.

Alarm delay Pc alarm

A45 PcAlrmDelay

The time delay is set in minutes. At min. setting the alarm is cancelled.

Alarm delay DI1 (an interrupted input will give alarm).

A27 DI1AlrmDelay

The time delay is set in minutes. At max. setting the alarm is cancelled.

Alarm delay DI2 (an interrupted input will give alarm).

A28 DI2AlrmDelay

The time delay is set in minutes. At max. setting the alarm is cancelled.

Alarm delay DI3 (an interrupted input will give alarm).

A29 DI3AlrmDelay

The time delay is set in minutes. At max. setting the alarm is cancelled.

Alarm limit for high temperature of the "Saux1" sensor

A32 Saux1 high

With setting = Off the alarm has been opted out.

Alarm delay from "Saux1" (A32)

A03 Alarm delay

If the limit value is exceeded, a timer function will commence. The alarm will not become active until the set time delay has been passed. The time delay is set in minutes.

Give the top button a brief push to zeroset the alarm and to have the message shown on the display.

Reset alarm

The function zerosets all alarms when set in pos. ON.

With data communication the importance of the individual alarms can be defined. Setting is carried out in the "Alarm destinations" menu.

Miscellaneous Settings

Choice of application

o61

The regulator can be configured in various ways. The use that is required out of the four uses available is set here. The functions for the four uses can be viewed on page 14. This menu must be set as the first of all menus, as it enables the associated settings to be set.

1. Show temperature and "c16" mode
2. Show pressure and "c16" mode
3. Show temperature and M&M mode
4. Show pressure and M&M mode

This setting cannot be made via data communication. It must be set directly on the controller.

Sensor type (Sc3, Sc4 and "Saux1") (see also overview page 21)

o06 Sensor type

Normally a Pt1000 sensor with great signal accuracy is used for temperature measurement and AKS 32R for pressure measurement. But a PTC sensor may also be used (r25 = 1000) in special situations.

All temperature sensors must be of the same kind.

In brine cooling the pressure measurements are replaced by temperature measurements.

The following settings are possible:

0=PT1000. 1=PTC1000. 2=PT1000 on sensors and on Po. 3=PTC1000 on sensors and on Po. 4=PT1000 on sensors and on Pc. 5=PTC1000 on sensors and on Pc. 6=PT1000 on sensors, on Po and on Pc. 7=PTC1000 on sensors, on Po and on Pc.

(If a temperature sensor is mounted on P0 or Pc, the respective settings in o20, 21, 47 and 48 will not be required).

Settings at water cooler application

o81 Ctrl.Sensor

Definition of the signal inlet when compressor regulation is controlled with signal from a temperature sensor:

1. Temperature signal on terminal 57-58 (P0 inlet)
2. Temperature signal on Saux inlet
3. Temperature signal on Sc4 inlet

(P0 min. function (A11) will not be affected by the definition)

If frost protection is required, you must connect a pressure transmitter on P0 and the temperature sensor must be connected to the Saux or Sc4 input. Select 1 or 2 at plants where there is no need for frost protection, the alarm "E2" can be suppressed by connecting the signal from the PC (terminal 61) to P0 (terminal 58).

Display and Communication

Display connection

o82

This is where you define the type of display that is connected to the controller

• Off: EKA 164
• On: EKA 165. The extended display with LEDs.

Read temperature at sensor "Saux1"

o49 Saux1 temp

Pressure transmitter's working range

Depending on the pressure, a pressure transmitter with a given working range is used. This working range must be set in the controller (e.g.: -1 to 12 bar The values must be set in bar if display in °C has been selected. And in psig, if °F has been selected.

If the values are to be set from the AKM programme, they must be set in bar.

• P0-Min. value: o20 P0MinTrsPres
• P0-Max. value: o21 P0MaxTrsPres
• Pc-Min. value: o47 PcMinTrsPres
• Pc-Max. value: o48 PcMaxTrsPres

Use of DI1 input

o78 Di1 control

The digital input can be connected to a contact function, and the contact can now be used for one of the following functions:

Setting / function:

• 0: DI input not used
• 1: Fan alarm when contact cuts out. Alarm "A34" is given.
• 2: Alarm function when the contact cuts out. Alarm "A28" is given. There is time delay for the alarm. Setting in "A27".

Use of DI4 input

o22 Di4 control

The digital input can be connected to a contact function, and the contact can now be used for one of the following functions:

Setting / function:

• 0: DI input not used
• 1: Regulation reference P0 displaced when contact is cut in
• 2: Alarm function when the contact cuts out. Alarm "A31" is given. There is no time delay.

Use of DI5 input

o37 Di5 control

The digital input can be connected to a contact function, and the contact can now be used for one of the following functions:

Setting / function:

• 0: DI input not used
• 1: Regulation reference Pc displaced when contact is cut in
• 2: Alarm function when the contact cuts out. Alarm "A32" is given. There is no time delay

Operating hours

The operating hours for the compressor relays can be read and set in the following menus. The read value is multiplied by 1000 to obtain the number of hours (f.ex. shows 2.1 for 2100 hours). On reaching 99.9 hours the counter stops and must now be reset to, say, 0. There will be no alarm or error message for counter overflow.

(In the AKM display the hour number has not been multiplied)

• Value for relay number 1 to 4: o23-o26 DO1-DO4 run hour
• Value for relay number 5 to 8: o50-o53 DO5-DO8 run hour

Refrigerant setting

o30 Refrigerant

Before refrigeration is started, the refrigerant must be defined. You may choose between the following refrigerants:

1=R12. 2=R22. 3=R134a. 4=R502. 5=R717. 6=R13. 7=R13b1. 8=R23. 9=R500. 10=R503. 11=R114. 12=R142b. 13=User defined. 14=R32. 15=R227. 16=R401A. 17=R507. 18=R402A. 19=R404A. 20=R407C. 21=R407A. 22=R407B. 23=R410A. 24=R170. 25=R290. 26=R600. 27=R600a. 28=R744. 29=R1270. 30=R417A. 31=R422A, 32=R413A. 33=R422D. 34=R427A. 35=R438A.

Warning: Wrong selection of refrigerant may cause damage to the compressor.

Other refrigerants: Select setting 13 here, and subsequently three factors have to be set - fac1, fac2 and fac3 - via AKM.

Manual control (stopped regulation only)

o18 - - -

From this menu the relays can be cut in and out manually. 0 gives no override, but a number between 1 and 10 will cut in a belonging relay. 1 will cut in relay number 1, 2 relay 2, etc.

11-18 will produce voltage on the analog output. In this way the relays on the external relay module can be activated. Setting 11 will give a voltage of 1.25 V, setting 12 will give 2.5 V, etc.

Frequency

o12 50 / 60 Hz (50=0, 60=1)

Set the net frequency.

Address and Special Settings

Address

o03, o04

If the controller is built into a network with data communication, it must have an address, and the master gateway of the data communication must then know this address. These settings can only be made when a data communication module has been mounted in the controller and the installation of the data communication cable has been completed. This installation is mentioned in a separate document "RC8AC". The address is set between 1 and 240 (gateway determined). The address is sent to the gateway when the menu is set in pos. ON.

Following installation of a data communication module, the controller can be operated on a par with the other controllers in ADAP-KOOL® refrigeration controls.

Access code

o05

If the settings in the controller are to be protected by a numerical code, you can set a numerical value between 0 and 100. If not, you can cancel the function with setting OFF.

Special settings

Outputs DO9 and DO10 are normally used for the "AKD start/stop" function and for the alarm function, but they may be redefined in special cases.

• DO9 function: o75 DO9 function
  0: AKD Start/stop
  1: Inject-on function (see drawing below)
  2: Boost ready function (see drawing below)
  3: Fan relay
  (If "c16" is set to 18, "o75" will automatically be set to unloader relay for compressor 3)
• DO10 function: o76 DO10 function
  0: Alarm relay
  1: Fan relay

Status on the digital inputs

The signal on the DI inputs can be read in the following menus:

• Status on DI 1: u10 DI 1 Status
• Status on DI 2: u37 DI 2 Status
• Status on DI 3: u87 DI 3 Status
• Status on DI 4: u88 DI 4 Status
• Status on DI 5: u89 DI 5 Status

Configuration settings (compressor and fan definitions, coupling mode and refrigerant) can only take place when regulation is stopped.

Warning! Direct start of compressors *

To prevent compressor breakdown parameter c01 and c07 should be set according to suppliers requirements or in general:

• Hermetic Compressors c07 min. 5 minutes
• Semihermetic Compressors c07 min. 8 minutes and c01 min. 2 to 5 minutes (Motor from 5 to 15 KW)

*) Direct activating of solenoid valves does not require settings different from factory (0)

DO9 function: Inject-on function

DO9 is here used for the Inject ON function. Here all the electronic expansion valves are closed when all the compressors are stopped and P0 > +Zone. Wiring is carried out as shown below. The function may however also be generated via data communication. In this way the relay output is made available for other applications.

Boost ready function

If two controllers are to capacity regulate the high-temperature part and the low-temperature part, respectively, they must be connected in such a way that low-temperature regulation cannot be started until the high-temperature part is operating. The signal can be taken from DO9 of one controller and received on the ON input of the other controller. Example:

Operating Status and Alarms

Operating status

The controller goes through some regulating situations where it is just waiting for the next point of the regulation. To make these "why is nothing happening" situations visible, you can see an operating status on the display. Push briefly (1s) the upper button. If there is a status code, it will be shown on the display. The individual status codes have the following meanings:

• S0: Regulation (EKC state: 0)
• S2: When the relay is operated, it must be activated for min. x minutes (cf. c01) (EKC state: 2)
• S5: Renewed cut-in of the same relay must not take place more often than every x minutes (cf. c07) (EKC state: 5)
• S8: The next relay must not cut in until x minutes have elapsed (cf.c11-c12) (EKC state: 8)
• S9: The next relay must not cut out until x minutes have elapsed (cf. c14-c15) (EKC state: 9)
• S10: Regulation stopped with the internal og external start/stop (EKC state: 10)
• S25: Manual regulation of outputs (EKC state: 25)
• S34: Safety cutout. Setting A30 is exceeded (EKC state: 34)

Alarm messages

Messages can be brought up on the display by briefly pressing the uppermost key. If there is more than one alarm, they can be scrolled through.

• A2: Low P0 (Alarms "Destinations": A02 Low P0 alarm)
• A11: No refrigerant has been selected (cf. o30) (Alarms "Destinations": A11 No RFG Sel)
• A17: High Pc (Alarms "Destinations": A17 Hi Pc alarm)
• A19 ....A26: Compr. fault. Interrupted signal on actual input (terminal 29-36) (Alarms "Destinations": A19..... A26 Comp._fault)
• A27: High temperature alarm for sensor "Saux1" (Alarms "Destinations": A27 Saux1 high)
• A28 .... A32: External alarm. Interrupted signal on input "DI1" /2/3/4/5 (Alarms "Destinations": A28..... A32 DI_Alarm)
• A34: Fan alarm. There is signal on DI1 input (Alarms "Destinations": A34 Fan fault)
• A45: Regulation stopped with setting or with external switch (Alarms "Destinations": A45 Stand by)
• E1: Error in the controller (Alarms "Destinations": E1 Ctrl. fault)
• E2: Control signal outside the range (short-circuited/interrupted) (Alarms "Destinations": E2 Out of range)

At water cooler management without frost protection may alarm from a not mounted P0 input suppressed by connecting the signal from the PC (terminal 61) to P0 (terminal 58).

Factory setting

If you need to return to the factory-set values, it can be done in this way:

• Cut out the supply voltage to the controller
• Keep the middle button pressed at the same time as you reconnect the supply voltage

Compressor Configuration Options

Compressor configuration when o61 =1 or 2

Setting "c16" will define the configuration. Setting "c08" will define coupling mode.

Capacity step: All capacity steps are presumed to be identical. The only exception is the settings c16 = 4 and 21 to 26.

Coupling mode:

• Coupling mode 1 = sequential operation.
• Coupling mode 2 = cyclic operation.
• Coupling mode 3 = cyclic and binary operation where the compressor capacities are, as follows:
  1: 9%
  2: 18%
  3: 36%
  4: 36%

There is cyclic coupling at 3 and 4, and binary on 1, 2 and 3/4. (for c16=4 only)

Couplings: When there is cyclic operation and connections with unloaders, there will in some capacity cut-ins and cut-outs be overlappings where the unloaders from either one compressor or another may be active. In such cases the unloaders on the compressor with the lowest number of hours will be cut in, and the others cut out. The changeover will take place at 6-second intervals.

Equalised operation: When c16 = 21 to 26, compressor 1 + belonging unloader must have the same capacity as each of the subsequent compressors. The unloading function will equalise the cut-in capacity when the subsequent compressors are cut in and out. Compressor 1 will always be operating.

Compressor configuration when o61 = 3 or 4

(Mix and Match used only on plants with up to 4 compressors.)

Survey of relays in Mix and Match operation:

This defines yourself how the relays are to be activated.

Example 1

Example 2

If capacity step 1 has to cut in relay number 3 only, you must set c17 to 4. If capacity step 2 has to cut in relay number 4 only, you must set c18 to 8. If capacity step 3 has to cut in relay numbers 3 and 4, you must set c19 to 12. Continue with a setting for c20 etc. until all capacity steps have been defined.

Condenser Couplings and Fan Control

Condenser couplings

When the compressor relays have been established, the turn comes to the fan relays. The first vacant relay (DO1-DO8) will become the first fan relay. It will be followed by the subsequent relays. If more relays are required than the vacant DO relays, a relay module can be connected to the analog output. The function is, as follows:

Diagram: AK-PC 530 outputs DO1-DO10 shown with numbered connections (1-4 for compressors, 8 for alarm, 8 for alarm, 8 for alarm, 8 for alarm). Below this, a representation of external fans connected to EKC 331 units.

External fans on EKC 331

If there are up to four external fans on an EKC 331:

Diagram: A graph showing output signal [V] vs. [%] capacity, with steps at 0, 1.25, 2.5, 3.75, 5.

Output signal from AK-PC 530

In EKC 331 the voltage range must be set to 0-5 V ("o10" = 6).

In EKC 331 the number of steps must be set to 4 ("o19" = 4) (also when fewer fans are connected).

Connection: AK-PC 530 (terminals 37, 38) to EKC 331 (terminals 15, 16).

If there are more than four external fans on two EKC 331 units:

Diagram: A graph showing output signal [V] vs. [%] capacity, with steps at 0, 1.25, 2.5, 3.75, 5, 6.25, 7.5, 8.75, 10.

Output signal from AK-PC 530

In the first EKC 331, set 0-5 V ("o10" = 6).

In the second EKC 331, set 5-10 V ("o10" = 7).

In both EKC's the number of steps must be set to 4 ("o19" = 4) (also when fewer fans are connected to the second EKC).

Connection: AK-PC 530 (terminals 37, 38) to EKC 331 (terminals 15, 16), and another EKC 331 (terminals 15, 16).

Alternating start-up of fans (only if c29 is 11 to 18)

The fans can be defined to start alternately when they have all been stopped. The first time regulation is started, fan 1 will be started first – the regulation determines whether additional fans will be started. After the next time all fans are stopped, fan 2 will be the first to be started, and so on. Fan 1 will again be the first fan to be started when the rotation has been through the total number of fans. If there is more than one fan on an EKC 331, it will not be possible to start the other fans first. Here, the fan with the lowest voltage step will always be the one which is started first.

Condenser capacity control via frequency converter

If the entire condenser capacity is to be controlled by a frequency converter, AK-PC 530 must send an analog signal about the required capacity ("c29" = 9). The signal varies from 0 to 10 V. Signal and capacity have the following context.

Diagram: A graph showing Voltage [V] vs. Capacity [%], with points at (0,0), (5,25), (10,50), (10,75), (10,100).

Operation and Display

Data communication

If the controller is extended with data communication, the operation can be performed from a system unit. The parameter names for the functions can be viewed in the right-hand column on pages 4-10. The importance of the alarms that are sent can be defined with the setting: 1 (High), 2 (Medium), 3 (Low) or 0 (No alarm).

Operation via external display

The values will be shown with three digits, and with a setting you can determine whether the pressures are to be shown in SI units (°C / bar) or US units (°F / psig.). There are three options for the display.

• EKA 165: To operate the controller and view the evaporation pressure. If the lowermost key is pressed, the condensation pressure will be shown briefly in the display. (If regulation is based only on the condensation pressure, the display will always show Pc). During normal operation the light-emitting diodes in the display will indicate where regulation is taking place: Highest + second highest : ++Zone, Second highest : +Zone, "None" : Neutral zone, Second lowest : -Zone, Lowest+ second lowest : - - Zone. The other LEDs on the display will show the functions that are active: Relays for compressors, Relays for fans, Input signals for the digital inputs. The optimization LED will light up when the reference is 2 K or more over the set point.
• EKA 163: If the condensation pressure is to be shown constantly, a display without operating keys can be connected.
• EKA 164: To operate the controller and view the evaporation pressure. If the lowermost key is pressed, the condensation pressure will be shown briefly in the display. Like the EKA 165, the LEDs in the display will show where the regulation is located.

The buttons on the display

When you want to change a setting, the upper and the lower buttons will give you a higher or lower value depending on the button you are pushing. But before you change the value, you must have access to the menu. You obtain this by pushing the upper button for a couple of seconds - you will then enter the column with parameter codes. Find the parameter code you want to change and push the mittle button. When you have changed the value, save the new value by once more pushing the mittle button.

Or short:

1. Push the upper button (long push) until a parameter is shown
2. Push one of the buttons and find the parameter you want to change
3. Push the middle button until the setting value is shown
4. Push one of the buttons and select the new value
5. Push the middle button again to conclude the setting

(A brief pushing will show the active alarm codes. See page 17.)

Menu Survey

Sequence

1. o61 must be set as the first parameter. This parameter determines which of the four operating interfaces (application mode) are activated. This must be set via the display keys. It cannot be set via data communication. (Active functions are shown below in shaded fields.)
2. Quick- start To get the system up and running quickly so that cooling can be commenced, start it by setting the following parameters (these parameters can only be set when the regulation is stopped, r12=0): r23, r28 and then either (c08, c09 and c16) or (c17 to 28) – continue with c29, o06, o30, o75, o76, o81 and finally r12=1.
3. Once the regulation is under way, you can go through the other parameters and adjust them in situ.

Regulation Parameters and Alarms

Data and Connections

Data

Ordering

Montage

Diagram: Shows mounting options for AK-PC 530 (DIN rail or wall mount) and display units.

Pressure transmitter / temperature sensor

Please refer to catalogue RKOYG...

Installation considerations

Accidental damage, poor installation, or site conditions, can give rise to malfunctions of the control system, and ultimately lead to a plant breakdown.

Every possible safeguard is incorporated into our products to prevent this. However, a wrong installation, for example, could still present problems. Electronic controls are no substitute for normal, good engineering practice.

Danfoss will not be responsible for any goods, or plant components, damaged as a result of the above defects. It is the installer's responsibility to check the installation thoroughly, and to fit the necessary safety devices.

Special reference is made to the necessity of signals to the controller when the compressor is stopped and to the need of liquid receivers before the compressors.

Your local Danfoss agent will be pleased to assist with further advice, etc.

Connections

PO/Pc: AKS 32R: 1 = Black = +, 2 = Blue = -, 3 = Brown = s

Compressor control with temperature

Diagram: Shows terminal connections for AK-PC 530, including power, relay outputs, digital inputs, and sensor inputs. Specific settings for o06 and o81 are indicated.

Necessary connections:

• Terminals 1-2: Supply voltage 24 V a.c.
• Terminals 4-19: Relay outputs for either compressors, unloaders or fan motors.
• Terminals 22-24: Alarm relay *. There is connection between 22 and 24 in alarm situations and when the controller is dead.
• Terminals 27-28: 24 V signal to start / stop of regulation
• Terminals 27-29: 24 V signal from the safety circuit DO 1
• Terminals 27-30: 24 V signal from the safety circuit DO 2
• Terminals 27-31: 24 V signal from the safety circuit DO 3
• Terminals 27-32: 24 V signal from the safety circuit DO 4
• Terminals 27-33: 24 V signal from the safety circuit DO 5
• Terminals 27-34: 24 V signal from the safety circuit DO 6
• Terminals 27-35: 24 V signal from the safety circuit DO 7
• Terminals 27-36: 24 V signal from the safety circuit DO 8
• Terminals 57-59: Suction pressure. Voltage signal from AKS 32R **
• Terminals 60-62: Condenser pressure. Voltage signal from AKS 32R **

Unloader

Diagram: Shows ON/OFF switch and 24V connection for unloader control.

If an output is used for an unloader it is not necessary to wire the belonging safety circuit. Ex. with an unloader on DO2 a connection on terminal 30 can be left out.

Application dependent connections

• Terminals 20-21: AKD start/stop *. The relay cuts in when the frequency converter has to start.
• Terminals 37-38: Voltage signal to external condenser control (see settings page 12)
• Terminals 39-41: Possibility of connecting an external display type EKA 163 or display of Pc
• Terminals 42-44: Possibility of connecting an external display type EKA 163 for display of P0, or EKA 165 for operation and display of P0
• Terminals 45-46: DI1 - Contact function for alarm signal
• Terminals 45-47: DI2 - Contact function for alarm signal
• Terminals 48-49: DI3 - Contact function for alarm signal
• Terminals 48-50: DI4 - Contact function for displacement of the suction pressure reference or for alarm signal.
• Terminals 51-52: DI5 - Contact function for displacement of the condenser pressure reference or for alarm signal.
• Terminals 51-53: Separate sensor Saux1. Sensor signal from AKS 11, AKS 12 or EKS 111
• Terminals 54-55: Out temperature (Sc3). Sensor signal from AKS 11, AKS 12 or EKS 111 (mounted if r33 =2 or 4)
• Terminals 54-56: Air temperature at condenser outlet. Sensor signal from AKS 11, AKS 12 or EKS 111

Data communication

Terminals 25-26: Mount only, if a data communication module has been mounted. For ethernet communication the plug connection RJ45 must be used. (LON FTT10 can also be connected in this way. It is important that the installation of the data communication cable be done correctly. Cf. separate literature No. RC8AC.

*) Relays DO9 and DO10 may in special cases be reconfigured so that they can be used as fan relays. See also page 9.

**)

• If the controller has to control only the compressor or the fans, respectively Pc and P0 sensor can be dispensed
• In brine systems temperature measurement at terminals 57-58 and 60-61 may be used instead of pressure measurement with AKS 32R. See also o06.

Safety Function

Exercising fans

On the setting c29 = 1-8 the last fans will hardly be activated during the winter. To ensure that the fans are 'exercised' a test will be carried out every 24 hours to check whether all relays have been in operation. The relays that have not been used will now be activated for 30 seconds, but with a pause of one hour between individual relays.

Override and Sensor Selection

Override

The controller contains a number of functions that can be used together with the override function in the master gateway. They can therefore only be used in combination with data communication.

The system unit registers the refrigeration point which handles the largest capacity (requires the lowest suction pressure). The parameter may be logged for use in a service situation.

Selecting sensor type and where the signal must be connected

Overview for setting o06

*) Supplies signal to frost protection.
** ) Will supply signal to floating condenser regulation if it is defined in r33 (r33 = 2 or 4).
***) With brine cooling where there should also be frost protection, connect the regulation sensor to either Sc4 or Saux (defined in o81).

Appendix

The PC reference

You may choose between four different regulation modes. Basically 1 or 2 are recommended. But if the plant is unstable it may become necessary to change over to 3 or 4.

1. PI regulation. Fixed reference i.e. constant condensing pressure.
2. PI regulation. Floating reference with outdoor temperature i.e. variable condensing pressure.
3. As "1", but with P regulation. A somewhat higher condensing pressure than indicated by the reference must be accepted here.
4. As "2", but with P regulation. A somewhat higher condensing pressure than indicated by the reference must be accepted here.

To limit the variation in the reference, if floating reference is chosen (mode 2 & 4), two limit values will have to be set. A max. limit (r30) and a min. limit (r31). The total regulation reference (r29) will not be able to go beyond these limits.

As a safeguard against too high condenser temperature a Pc max. value (A30) also has to be set. If the temperature approaches this value a cutout of the compressor will be started.

1. PI regulation with fixed reference

Diagram: Graph showing Pc vs. time, illustrating Ref r29, Setpoint r28, limits r30, r31, and Pc max A30. DI 5 = ON is indicated.

The reference at any time, on the basis of which the controller regulates, can be seen in "r29". A reference (r28) is set here which with certainty can cope with all kinds of loads.

If you need to raise the condensing temperature for, say, heat recovery, an offset value (r34) has to be set. The DI5 function must be defined to 1. When a signal is subsequently received on the DI5 input the reference will be raised.

2. PI regulation with floating reference

Diagram: Graph showing Pc vs. time, illustrating Ref r29, Setpoint r28, limits r30, r31, Pc max A30, and Sc3/r56. DI 5 = ON is indicated.

The reference follows the outdoor temperature Sc3. If the outdoor temperature drops one degree the reference will also drop one degree. The reference is adjusted according to the compressor capacity with max. Xp value.

If you need to raise the condensing temperature for, say, heat recovery, the setpoint (r28) must be set to this temperature.

The DI5 function must be defined to 1. When a signal is subsequently received on the DI5 input the reference will be changed to the r28 setting. The reference at any time, on the basis of which the controller regulates, can be seen in "r29". If there is sensor failure on the outdoor temperature sensor the reference will change over to the r28 setting.

3. P regulation with fixed setting

Diagram: Graph showing Pc vs. Pc ref, illustrating steps and Xp band.

As "1", but an increasing deviation from the reference must be accepted as the controller uses the difference between the actual condenser temperature and the set reference for indicating the number of fans that has to be cut in.

The number of fan steps is divided up based on the Xp value. Recommended setting for Xp is the ΔT of the condenser, typically 10 to 15 K. The cut-in and cut-out of fans are shown in the drawing. If the entire condenser capacity is controlled by speed regulation, the capacity will be indicated on the broken line.

4. P regulation with floating reference

Diagram: Graph showing Pc vs. Pc - Sc3, illustrating steps and Xp band.

As "2", but an increasing deviation from the reference must be accepted as the controller uses the difference between the actual condenser temperature and the actual outdoor temperature for indicating the number of fans that has to be cut in. (The first "r56-degrees" are left out, as there must be a possibility of cooling via the condenser).

The number of fan steps is divided up based on the Xp value. Recommended setting for Xp is the ΔT of the condenser, typically 10 to 15 K. The cut-in and cut-out of fans are shown in the drawing. If the entire condenser capacity is controlled by speed regulation, the capacity will be indicated on the broken line.

Important settings for avoiding unwanted alarms

• When r33 = 1 or 2: Set Pc ref max. to at least 5 K under Pc max. (A30).
• When r33 = 3 or 4: Set Pc ref max. to at least (Xp value +5) K under Pc max. (A30).

List of Literature

Installation guide for extended operation: RC8AC--

Here you can see how a data communication connection to ADAP-KOOL® Refrigeration controls can be established.