Danfoss AK-PC 530 Capacity Controller

Introduction

Application

The controller is used for capacity regulation of compressors or condensers in small refrigerating systems. The number 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 data communication

Regulation

Regulation is based on signals from one pressure transmitter for compressor regulation and one pressure transmitter for 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 are reserved for the alarm function and for the "VLT start/stop" function. Relays are reserved for compressor capacities starting from DO1, DO2, etc. The remaining relays up to and including DO8 are available for fans. If more are required, one or more relay modules type EKC 331 with a maximum of eight steps can be connected. The signals to these modules are taken from the controller's analog output. Another solution is 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 a maximum of eight for compressors and a maximum of eight fans).

Diagram Description: A schematic shows the AK-PC 530 controller connected to pressure transmitters (Po, Pc), temperature sensors (SC3, SC4), and multiple output terminals (DO1-DO8) for compressors and fans, illustrating typical system wiring for regulation.

Function

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 "approaches" the neutral zone, the controller will make no changes to 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 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 is cut out first.

Cyclic (first in - first out)

The relays are coupled so that the operating time of the individual relays becomes equalized. At each cut-in, the regulation scans the individual relays' timers, cutting in the relay with the least time on it. At each cut-out, a similar process occurs; the relay cut out is the one with the most hours on its timer.

Diagram Description: A graph illustrates pressure versus time, showing different regulation zones (++zone, +zone, Neutral Zone, -zone, --zone) and how capacity is adjusted based on pressure changes. Another diagram shows sequential relay activation (R1, R2, R3, R4) over time, corresponding to capacity steps (25%, 50%, 75%, 100%). A third diagram shows cyclic relay activation with equalized operating times (h). A fourth diagram depicts compressor (C) and unloader (L) control using relays, showing equalized operating times for compressor motors and unloaders.

Suvey of functions

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

Function Details

Condenser reference

The regulation reference is shown here.

Set point limitation

With these settings the setpoint can only be set between the two values. (This also applies to regulations where the Xp band lies above the reference).

• Max. permissible setpoint value.
• Min. permissible setpoint value.

Correction of pressure measurement

An offset adjustment of the registered pressure can be made.

Dimensioning temperature Dim tm

The mean temperature difference across the condenser at maximum load (tm difference at max. load). This is the temperature difference between the air and condensing temperature.

Dimensioning temperature Min tm

The mean temperature difference across the condenser at the lowest relevant compressor capacity (tm difference at min. load). This is the temperature difference between the air and condensing temperature.

Reading your P0

This is where you can see the actual pressure that is being measured by the pressure transmitter. The value is part of the regulation, since the regulation signal for capacity regulation originates from the pressure transmitter. The value is part of the frost protection regulation, since the regulation signal for capacity regulation originates from the temperature sensor.

Reading your T0

This is where you can see the actual pressure being measured by the sensor chosen for capacity regulation (the sensor is defined in o81). The value is displayed in °C.

Compressor capacity

Running time

To prevent frequent start/stop, values have to be set for how the relays are to cut in and out.

• Min. ON time for relays. (The time is not used if the relay cuts an unloader in or out).
• Min. time period between cut-in of the same relay. (The time is not used if the relay cuts an unloader in or out).

Setting for neutral zone regulation

• Regulation band over the neutral zone
• Time delay between step cut-ins in the regulation band over the neutral zone
• Time delay between step cut-ins in the regulation band over the "+Zone band".
• Regulation band under the neutral zone
• Time delay between step cut-outs in the regulation band under the neutral zone
• Time delay between step cut-outs in the regulation band under the "-Zone band"

Pump down limit

The factory setting for this function is OFF. Activate by setting a value corresponding to pressure under the zone and over the P0 min. limit. The function keeps the last capacity step going until the pressure comes down to the pump down limit. When this value is reached, the last compressor will cut out. Do not reconnect capacity until the pressure is once more above the neutral zone.

Compressor configuration

This setting only applies if "o61" is set to "1" or "2". Here you set the predefined combination of number of compressors and any unloaders.

• 1 = One compressor
• 2 = Two compressors
• 3 = Three
• 4 = Four
• 5 = One compressor + one unloader
• 6 = One compressor + two unloaders
• For 7 to 26: See survey on page 11

If the compressors are of different sizes, the setting must be selected to either 4 or 0. At position 0, it is up to you to determine which relays have to be drawn on at each of the required capacity steps.

Selection of coupling mode (See also the overview page 11)

1. Sequential: First relay 1 cuts in, then relay 2, etc. Cut-out takes place in the opposite sequence ("First in, last out").
2. Cyclic: An automatic operating time equalization is arranged here, so that all steps with motor connection will have the same operating time.
3. Binary and cyclic (only for four compressors with "c16" set to 4).

Unloaders' cutin and cutout mode

The relays for unloaders can be set to switch on when more capacity is required (setting = 0), or they can switch off when more capacity is called for (setting = 1).

Mix and Match Operation

This function cuts the relay in and out depending on the definitions in "c17" to "c28". ("c17" to "c28" are only used if "o61" is selected to "3" or "4"). In Mix and Match couplings, 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 on 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.

Continue defining steps.

Manual control of compressor capacity

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

Manual control

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

Definition of condenser and number of fans

Here you set the number of fan steps with which regulation has to be carried out (but a maximum of 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

Read temperature at sensor Sc4 (sensor is only used for monitoring)

Regulation parameters for the condenser regulation

• Proportional band Xp (P = 100/Xp): If the Xp value is increased, the regulation becomes steadier.
• I: Integration time Tn: If the Tn value is increased, the regulation becomes steadier.

Manual control of condenser capacity

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

Manual control

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

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

Speed control stop value

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

Alarm

The controller can give alarms in different situations. When there is an alarm, the light-emitting diodes (LEDs) 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).

Alarm settings

• P0 min. (Alarm and safety function, see also page 20.): 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: The time delay is set in minutes. At minimum setting, the alarm is cancelled.
• Pc max. (Alarm and safety function, see also page 20.): 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: The time delay is set in minutes. At minimum setting, the alarm is cancelled.
• Alarm delay DI1 (an interrupted input will give alarm): The time delay is set in minutes. At maximum setting, the alarm is cancelled.
• Alarm delay DI2 (an interrupted input will give alarm): The time delay is set in minutes. At maximum setting, the alarm is cancelled.
• Alarm delay DI3 (an interrupted input will give alarm): The time delay is set in minutes. At maximum setting, the alarm is cancelled.
• Alarm limit for high temperature of the "Saux1" sensor: With setting = Off, the alarm has been opted out.
• Alarm delay from "Saux1" (A32): 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 zero-set the alarm and to have the message shown on the display.

Miscellaneous

Choice of application

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

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

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

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

• 0. Temperature signal on terminal 57-58 (P0 inlet)
• 1. Temperature signal on Saux inlet
• 2. 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 Input Configuration

Display connection

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"

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.

Use of DI1 input

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

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

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 (e.g., shows 2.1 for 2100 hours). On reaching 99.9 hours, the counter stops and must be reset to 0. There will be no alarm or error message for counter overflow.

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

Refrigerant setting

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 must be set - fac1, fac2, and fac3 - via AKM.

Manual control (stopped regulation only)

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

Set the net frequency.

Data Communication and Special Settings

Address

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 position ON.

Access code

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: 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: 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
• Status on DI 2
• Status on DI 3
• Status on DI 4
• Status on DI 5

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, parameters c01 and c07 should be set according to supplier 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 used for the Inject ON function. Here, all electronic expansion valves are closed when all compressors are stopped and P0 > +Zone. Wiring is carried out as shown below. The function may also be generated via data communication, making the relay output available for other applications.

Diagram Description: Wiring diagram for DO9 Inject-on function, showing connections to AKC 114, 115, 116 or EKC 414A/514.

Boost ready function

If two controllers are to capacity regulate the high-temperature part and the low-temperature part, respectively, they must be connected so 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 Diagram: Shows two AK-PC 530 controllers (A and B) connected for boost ready function, where controller A's DO9 output connects to controller B's ON input.

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

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
• A11: No refrigerant has been selected (cf. o30)
• A17: High Pc
• A19 ....A26: Compr. fault. Interrupted signal on actual input (terminal 29-36)
• A27: High temperature alarm for sensor "Saux1"
• A28 .... A32: External alarm. Interrupted signal on input "DI1" /2/3/4/5
• A34: Fan alarm. There is signal on DI1 input
• A45: Regulation stopped with setting or with external switch
• E1: Error in the controller
• E2: Control signal outside the range (short-circuited/interrupted)

* At water cooler management without frost protection, an alarm may occur 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.

Alarm Destinations

• A02 Low P0 alarm
• A11 No RFG Sel
• A17 Hi Pc alarm
• A19..... A26 Comp._fault
• A27 Saux1 high
• A28..... A32 DI_Alarm
• A34 Fan fault
• A45 Stand by
• E1 Ctrl. fault
• E2 Out of range

Compressor and Fan Configuration

Compressor configuration when o61 = 1 or 2

This is where you can choose between the options shown. 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 equalize 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

This is where you must define yourself how the relays are to be activated. (Mix and Match is used only on plants with up to 4 compressors).

Survey of relays in Mix and Match operation

Diagram Description: A table shows compressor connections for different relay numbers and capacity steps, with settings for C16 and C08.

Example 1

Settings: c17 to 1, c18 to 2, c19 to 3, c20 to 4, c21 to 5, c22 to 6, c23 to 7.

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

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 Description: Schematics illustrate condenser fan control using AK-PC 530 and EKC 331 relay modules for different fan configurations (up to 4 fans, more than 4 fans). It shows output signals from AK-PC 530 and required settings for EKC 331.

Diagram Description: Wiring diagrams show connections between AK-PC 530 and EKC 331 units for fan control.

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.

Operation Modes

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 middle button. When you have changed the value, save the new value by once more pushing the middle 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 underway, you can go through the other parameters and adjust them in situ.

Parameter Tables

SW: 1.3x

Regulation Parameters and Control

Service and Safety Functions

Service

The controller can give the following messages

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

Safety function

Exercising fans

On 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 Functions 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: PC Reference Modes

The regulation functions are explained in more detail below.

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.

The different regulation modes are as follows:

1. PI regulation with fixed reference

Diagram Description: A graph shows PC reference (r29) and setpoint (r28) over time, illustrating PI regulation with a fixed reference, including limits (A30, r30, r31) and offset (r34). A DI5 input signal can raise the reference.

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.

2. PI regulation with floating reference

Diagram Description: A graph shows PC reference (r29) and setpoint (r28) over time, illustrating PI regulation with a floating reference influenced by outdoor temperature (Sc3) and DI5 input. It includes limits (A30, r30, r31) and offset (r34).

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 Description: A graph shows PC reference and setpoint over time, illustrating P regulation with fixed setting. It indicates that deviation from the reference is accepted, and fan steps are divided based on Xp value.

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 Description: A graph shows PC reference and setpoint over time, illustrating P regulation with floating reference influenced by outdoor temperature. It indicates deviation acceptance and fan steps based on Xp value.

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.

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