Danfoss AK-PC 710 User guide

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Design Guide

Capacity controller

AK-PC 710

ADAP-KOOL® Refrigeration control systems

Contents

1. Introduction ............................................................................. 3

Application .................................................................................................. 3

Function overview ............................................................................ 3

Principles...................................................................................................... 4

2. Design of the controller ..........................................................7

Module survey ........................................................................................... 8

Common data for modules .................................................................10

Controller ...........................................................................................12

Extension module AK-XM 102A / AK-XM 102B .....................14

Extension module AK-XM 204A / AK-XM 204B .....................16

Extension module AK-OB 110 ....................................................18

Extension module AK-OB 101A..................................................19

Extension module EKA 163B / EKA 164B / EKA 166 ............ 20

Power supply module AK-PS 075 ..............................................21

Select application ................................................................................... 22

General ................................................................................................ 22

Applications ...................................................................................... 22

Ordering ..................................................................................................... 33

3. Mounting and wiring .............................................................35

Mounting ................................................................................................... 36

Mounting of analog output module ........................................ 36

Mounting of extension module on the basic module ....... 37

Wiring .......................................................................................................... 38

4. Conguration and operation ................................................39

Conguration via service tool AK-ST 500 .......................................41

Connect PC or PDA ......................................................................... 41

Authorization .................................................................................... 42

Unlock the conguration of the controllers ..........................43

System setup ....................................................................................44

Set plant type ................................................................................... 45

Set control of compressors ..........................................................46

Setup control of condenser .........................................................49

Conguration of inputs and outputs .......................................50

Set alarm priorities..........................................................................52

Lock conguration ..........................................................................54

Check conguration .......................................................................55

Check of connections ............................................................................ 57

Check of settings.....................................................................................59

Schedule function .................................................................................. 61

Installation in network .......................................................................... 62

First start of control ................................................................................63

Start the control ............................................................................... 64

Manual capacity control ............................................................... 65

Quick setup ............................................................................................... 66

EKA 164, EKA 166 or AKM operation ...............................................67

5. Regulating functions .............................................................73

Suction group ..........................................................................................74

Controlling sensor...........................................................................74

Reference ...........................................................................................74

Capacity control of compressors ...............................................75

Capacity distribution methods ........................................... 76

Power pack types – compressor combinations ............77

Compressor timers ..................................................................79

Load shedding ..........................................................................80

Injection ON .............................................................................. 80

Safety functions ............................................................................... 81

Condenser ................................................................................................. 82

Capacity control of condenser ...................................................82

Reference for condensing pressure ..........................................82

Capacity distribution ..................................................................... 84

Step regulation ........................................................................................84

Speed regulation ....................................................................................84

Condenser couplings .....................................................................84

Safety functions for condenser .................................................. 85

Separate monitoring functions .........................................................85

Miscellaneous ..........................................................................................86

Appendix A – Compressor combinations and coupling pat-

terns ............................................................................................................. 89

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1. Introduction

Application

AK-PC 710 is a complete regulating unit for capacity control of compressors and condensers in refrigeration systems. In addition to capacity control the controllers can give signals to other controllers about the operating condition, e.g. forced closing of expansion valves, alarm signals and alarm messages.

Function overview

AK-PC 710

Application

Regulation of a compressor group x

Both compressor group and condenser group x

Regulation of compressor capacity

Regulation sensor P0

PI-regulation x

Max. number of compressor steps 6

Identical compressor capacities x

Dierent compressor capacities x

Sequential operation (rst in / last out) x

Speed regulation of 1 compressor x

Run time equalisation x

Min. restart time x

Min. On-time/ Min O time x

Suction pressure reference

Override via P0 optimization x

Override via “night setback” x

The controller’s main function is to control compressors and condensers so that operation all the time takes place at the energy-optimum pressure conditions. Both suction pressure and condensing pressure are controlled by signals from pressure transmitters. Capacity control can be carried out by suction pressure P0.

Among the dierent functions are:

- Capacity control of up to 6 compressors

- Speed control of one compressor

- One safety input for each compressor

- Option for capacity limitation to minimize consumption peaks

- When the compressor stops, signals can be transmitted to appliance controllers so that the electronic expansion valves will be closed (signal via data communication)

- Safety monitoring of high pressure / low pressure / discharge temperature

- Capacity control of up to 6 fans

- Step coupling, speed regulation or a combination

- Floating reference with regard to outside temperature

- Safety monitoring of fans

- The status of the outputs and inputs is shown by means of lightemitting diodes on the front panel

- Alarm signals can be generated directly from the controller and via data communication

- Alarms are shown with texts so that the cause of the alarm is easy to see.

- Plus some completely separate functions that are totally independent of the regulation – such monitoring of liquid level and room temperature.

Regulation of condenser capacity

Regulation sensor Pc

Step regulation x

Max. number of steps 6

Speed regulation x

Step and speed regulation x

Condenser pressure reference

Floating condensing pressure reference x

Safety functions

Min. suction pressure x

Max. suction pressure x

Max. condensing pressure x

Max. discharge gas temperature x

Min. / Max. superheat x

Safety monitoring of compressors x

Common high pressure monitoring of compressors x

Common low pressure monitoring of compressors x

Safety monitoring of condenser fans x

Monitoring of room temperature x

Monitoring of liquid level x

Monitoring of frequency converter (VSD) x

Miscellaneous

Inject On function via data communication x

Option for connection of separate display 2

Option for connection of graphic display 1

SW = 1.4

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Principles

The great advantage of this series of controllers is that it can be extended as the size of the plant is increased. It has been developed for refrigeration control systems, but not for any specic application – variation is created through the read-in software and extension with up to 3 modules. It is the same modules that are used for each regulation and the composition can be changed, as required. With these modules (building blocks) there is up to 40 various kinds of regulations. But it is you who must help adjusting the regulation to the actual needs – these instructions will assist you to nd your way through all the questions so that the regulation can be dened and the connections made.

Controller

Top part

Advantages

• The controller’s size can “grow” as systems grow

• The software can be set for one or more regulations

• Several regulations with the same components

• Extension-friendly when systems requirements are changed

• Flexible concept:

- Controller series with common construction

- One principle – many regulation uses

- modules are selected for the actual connection requirements

- The same modules are used from regulation to regulation

Extension modules

Bottom part

The controller is the cornerstone of the regulation. The module has inputs and outputs capable of handling small systems.

• The bottom part – and hence the terminals – are the same for all controller types.

• The top part contains the intelligence with software. This unit will vary according to controller type. But it will always be supplied together with the bottom part.

• In addition to the software the top part is provided with connections for data communication and address setting.

Examples

A regulation with few connections can be performed with the controller module alone

If the system grows and more functions have to be controlled, the regulation can be extended. With extra modules more signals can be received and more relays cut in and out – how many of them – and which – is determined by the relevant application.

If there are many connections one or more extension modules must be mounted

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Direct connection

Setup and operation of an AK controller must be accomplished via the “AK-Service Tool” software program.

The programme is installed on a PC, and setup and operation of the various functions are carried out via the controller’s menu displays.

Displays

The menu displays are dynamic, so that dierent settings in one menu will result in dierent setting possibilities in other menus.

A simple application with few connections will give a setup with few settings. A corresponding application with many connections will give a setup with many settings. From the overview display there is access to further displays for the compressor regulation and the condenser regulation. At the bottom of the display there is access to a number of general functions, such as “time table”, “manual operation”, “log function”, “alarms”, and “service” (conguration).

Network linking

The controller can be linked up into a network together with other controllers in an ADAP-KOOL® refrigeration control system. After the setup operation can be performed at a distance with, say, our software program type AKM.

Users

The controller comes supplied with several languages, one of which can be selected and employed by the user. If there are several users, they may each have their choice of language. All users must be assigned a user prole which either gives access to full operation or gradually limits the operation to the lowest level that only allows you “to see”.

External display

An external display can be tted in order for P0 (Suction) and Pc (Condensing) readings to be displayed. The setup can be carried out on a display with control buttons. The various functions are selected via a menu system. If display of operational compressors, fans and functions is required, display type EKA 166 can be tted. Med det graske display AK-MMI kan der både foretages opsætning og udlæsning.

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Light-emitting diodes

A number of light-emitting diodes makes it possible to follow the signals that are received and transmitted by the controller.

Log

From the log function you can dene the measurements you wish to be shown. The collected values can be printed, or you may export them to a le. You can open the le in Excel.

If you are in a service situation you can show measurements in a trend function. The measurements are then made real-time and displayed instantly.

■ Power

■ Comm

■ DO1 ■ Status

■ DO2 ■ Service Tool

■ DO3 ■ LON

■ DO4

■ DO5 ■ Alarm

■ DO6

■ DO7

■ DO8 ■ Service Pin

Slow ash = OK Quick ash = answer from gateway Constantly ON = error Constantly OFF = error

Flash = active alarm/not cancelled Constant ON = Active alarm/cancelled

Alarm

The display gives you an overview of all active alarms. If you wish to conrm that you have seen the alarm you can cross it o in the acknowledge eld. If you want to know more about a current alarm you can click on it and obtain an information display on the screen.

A corresponding display exists for all earlier alarms. Here you can upload information if you need further details about the alarm history.

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2. Design of the controller

This controller can be congured to one of the 40 xed applications.

• There are 20 applications with dierent numbers of compressors and condenser fans.

• The same applications can also be carried out with speed control of one compressor.

• The condenser fans can be connected in steps or speed controlled.

The selected application has xed dened connecting points. These cannot be changed.

In addition to the controller module, one or more of the following modules should be used. The selected application determines:

• Output module with relays

• Input module for registering on/o signals

• Analogue output module for controlling one or two frequency converters. One for one compressor and one for the condenser fans.

This section denes the application and which modules should be used.

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Module survey

• Controller module – capable of handling minor plant requirements.

• Extension modules. When the complexity becomes greater and additional inputs or outputs are required, modules can be attached to the controller. A plug on the side of the module will transmit the supply voltage and data communication between the modules.

• Top part The upper part of the controller module contains the intelligence. This is the unit where the regulation is dened and where data communication is connected to other controllers in a bigger network.

Extension module with additional analog inputs

External display for suction pressure etc.

• Connection types There are various types of inputs and outputs. One type may, for example, receive signals from sensors and switches, another may receive a voltage signal, and a third type may be outputs with relays etc. The individual types are shown in the table below.

• Fixed connection When a regulation is planned (set up) it will generate a need for a number of connections distributed on the mentioned types. This connection must be made as shown in the following diagrams.

Extension module with additional relay outputs and additional analog inputs.

Controller with analog inputs and relay outputs.

Top part

Extension module with 2x analog output signals

The module with additional relay outputs is also available in a version where the top part is provided with change-over switches so that the relays can be overridden.

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1. Controller

Type Function Application

AK-PC 710

Controller for capacity control of up to 6 compressors and up to 6 condenser fans

Compressor / Condenser / Both

2. Extension modules and survey of inputs and outputs

Type Analog

inputs

For sensors, pressure transmitters etc.

Controller 11 4 4 - - - -

Extension modules

AK-XM 102A 8

AK-XM 102B 8

AK-XM 204A 8

AK-XM 204B 8 x

AK-OB 110 2

On/O outputs On/o supply voltage

Relay (SPDT)

Solid state Low voltage

(DI signal)

(max. 80 V)

High voltage (max. 260 V)

Analog outputs

0-10 V d.c. For override of

Module with switches

relay outputs

3. AK operation and accessories

Type Function Application

Operation

AK-ST 500 Software for operation of AK controllers AK-operation

- Cable between PC and AK controller AK - Com port

- Cable between PC and AK controller AK- USB

Accessories Power supply module 230 V / 115 V to 24 V

AK-PS 075 18 VA Supply for controller

Accessories External display that can be connected to the controller module. For showing, say, the suction pressure

EKA 163B Display

EKA 164B Display with operation buttons

EKA 166 Display with operation buttons and LED's for inputs and outputs

AK-MMI Graphic display with operation

Accessories Real time clock for use in controllers that require a clock function, but are not wired with data communication.

AK-OB 101A Real time clock with battery backup. To be mounted in an AK controller

Cable between zero modem cable and AK controller / Cable between PDA cable and AK controller

Cable between display and controller Length = 2 m, 6 m

Cable between graphic display and controller Length = 0.8 m, 1.5 m, 3 m

AK - RS 232

On the following pages there is data specic to each module.

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Common data for modules

Supply voltage 24 V d.c./a.c. +/- 20%

Power consumption AK-__ (controller) 8 VA

AK-XM 102 2 VA

AK-XM 204 5 VA

Analog inputs Pt 1000 ohm /0°C Resolution: 0.1°C

Pressure transmitter type AKS 32R / AKS 32 (1-5 V)

Voltage signal 0-10 V

Contact function (On/O) On at R < 20 ohm

On/o supply voltage inputs Low voltage

Relay outputs SPDT

Solid state outputs Used for control of compressor relay Max. 240 V a.c. , Min. 48 V a.c.

Ambient temperature During transport -40 to 70°C

0 / 80 V a.c./d.c.

High voltage 0 / 260 V a.c.

AC-1 (ohmic) 4 A

AC-15 (inductive) 3 A

U Min. 24 V

Accuracy: +/- 0.5°C

Resolution:1 mV Accuracy +/- 10 mV Max. connection of 5 pressure transmitters on one module

O at R > 2K ohm (Gold -plated contacts not necessary)

O: U < 2 V On: U > 10 V

O: U < 24 V On: U > 80 V

Max. 230 V Low and high voltage must not be connected to the same output group

Max. 0.5 A, Leak < 1 mA

During operation -20 to 55°C ,

0 to 95% RH (non condensing) No shock inuences / vibrations

Enclosure Material PC / ABS

Class IP10 , VBG 4

Mounting For mounting on panel wall or DIN rail

Weight with screw terminals modules in100- / 200- / controller-series Ca. 200 g / 500 g / 600 g

Approvals EU low voltage directive and EMC require-

ments are complied with

UL 873,

The mentioned data applies to all modules. If data is specic, this is mentioned together with the module in question.

Capacitive load

The relays cannot be used for the direct connection of capacitive loads such as LEDs and on/o control of EC motors. All loads with a switch mode power supply must be connected with a suitable contactor or similar.

LVD tested according to EN 60730 EMC tested Immunity according to EN 61000-6-2 Emission according to EN 61000-6-3

UL le number: E166834 for XM UL le number: E31024 for PC

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Dimensions

AK-PC 710

AK-PC 710 + AK-XM 102

AK-PC 710 + AK-XM 204 + AK-XM 102

AK-PC 710 + AK-XM 204 + AK-XM 102 + AK-XM 102

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Controller

Function

There are several controllers in the series. The function is determined by the programmed software, but outwardly the controllers are identical – they all have the same connection possibilities:

11 analog inputs for sensors, pressure transmitters, voltage signals

and contact signals.

8 digital outputs, with 4 Solid state outputs and 4 relay outputs

Supply voltage

24 V a.c. or d.c. to be connected to the controller. The 24 V must not be retransmitted and used by other controllers as it is not galvanically separated from inputs and outputs. In other words, you must use a transformer for each controller. Class II is required. The terminals must not be earthed. The supply voltage to any extension modules is transmitted via the plug on the right-hand side. The size of the transformer is determined by the power requirement of the total number of modules.

The supply voltage to a pressure transmitter can be taken either from the 5 V output or from the 12 V output depending on transmitter type.

Data communication

If the controller is to be included in a system, communication must take place via the LON connection. The installation has to be made as mentioned in the separate instructions for LON communication.

Address setting

When the controller is connected to a gateway type AKA 245, the controller’s address must be set between 1 and 119. (If it is a system manager AK-SM .., then 1-999).

Service PIN

When the controller is connected to the data communication cable the gateway must have knowledge of the new controller. This is obtained by pushing the key PIN. The LED “Status” will ash when the gateway sends an acceptance message.

Operation

The conguration operation of the controller must take place from the software programme “Service Tool”. The program must be installed on a PC, and the PC must be connected to the controller via the network plug on the front of the unit.

Light-emitting diodes

There are two rows with LED’s. They mean: Left row:

• Voltage supply to the controller

• Communication active with the bottom PC board (red = error)

• Status of outputs DO1 to DO8

Right row:

• Software status (slow ash = OK)

• Communication with Service Tool

• Communication on LON

• Alarm when LED ashes

- 3 LED’s that are not used

• “Service Pin” switch has been activated

Address

Keep the safety distance!

Low and high voltage must not be connected to the same output group

■ Power

■ Comm

■ DO1 ■ Status

■ DO2 ■ Service Tool

■ DO3 ■ LON

■ DO4

■ DO5 ■ Alarm

■ DO6

■ DO7

■ DO8 ■ Service Pin

Slow ash = OK Quick ash = answer from gateway Constantly ON = error Constantly OFF = error

Flash = active alarm/not cancelled Constant ON = Active alarm/cancelled

A small module (option board) can be placed on the bottom part of the controller. The module is described later in the document.

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Point

Point 1 2 3 4 5 6 7 8 9 10 11

Type AI1 AI2 AI3 AI4 AI5 AI6 AI7 AI8 AI9 AI10 AI11

Terminal 15: 12 V Terminal 16: 5 V

Terminal 27: 12 V Terminal 28: 5 V

Analog inputs on 1 - 11

Solid state outputs on 12 - 15

Relay fx 230 V a.c.

Signal Signal

Pt 1000 ohm/0°C

Saux1 Sc3 SS Sd

AKS 32R

3: Brown

2: Blue

1: Black

P0 Pc

AKS 32

3: Brown

2: Black

1: Red

On/O Ext.

Main switch

Day/ Night

PLP PHP LL

Comp 1-6

Fan 1

Alarm

Option Board

Please see the signal on the page with the module.

24 and 25 used only when "Option board tted"

type

Pt 1000

AKS 32R/ AKS 2050

-1 - xx bar

AKS 32

-1 - zz bar

Active at:

Closed

Open

Active at:

O

Relay outputs on 16 - 19

Point 12 13 14 15 16 17 18 19

Type DO1 DO2 DO3 DO4 DO5 DO6 DO7 DO8

Signal Module Point

Terminal

1 (AI 1) 1 - 2

2 (AI 2) 3 - 4

3 (AI 3) 5 - 6

4 (AI 4) 7 - 8

5 (AI 5) 9 - 10

6 (AI 6) 11 - 12

7 (AI 7) 13 - 14

8 (AI 8) 19 - 20

9 (AI 9) 21 - 22

10 (AI 10) 23 - 24

11 (AI 11) 25 - 26

12 (DO 1) 31 - 32

Function and terminal number is mentioned in the actual diagram

13 (DO 2) 33 - 34

14 (DO 3) 35 - 36

15 (DO 4) 37 - 38

16 (DO 5) 39 - 40- 41

17 (DO6) 42 - 43 - 44

18 (DO7) 45 - 46 - 47

19 (DO8) 48 - 49 - 50

24 -

25 -

Terminal 17, 18, 29, 30: (Cable screen)

Signal type /

Active at

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Extension module AK-XM 102A / AK-XM 102B

Function

The module contains 8 inputs for on/o voltage signals.

Signal

AK-XM 102A is for low voltage signals. AK-XM 102B is for high voltage signals.

Supply voltage

The supply voltage to the module comes from the previous module in the row.

Light-emitting diodes

They indicate:

• Voltage supply to the module

• Communication with the controller is active (red = error)

• Status of the individual inputs 1 to 8 (when lit = voltage)

AK-XM 102A

Max. 24 V

On/O: On: DI > 10 V a.c. O: DI < 2 V a.c.

AK-XM 102B

Max. 230 V

On/O: On: DI > 80 V a.c. O: DI < 24 V a.c.

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Point

Point 1 2 3 4

Type DI1 DI2 DI3 DI4

Point 5 6 7 8

Type DI5 DI6 DI7 DI8

Signal Active at

AK-XM 102A: Max. 24 V AK-XM 102B: Max. 230 V

Day/ Night

Comp. safety 1-6

Cond.fan safety

Closed

(voltage on)

Open

(voltage o)

Signal Module Point Terminal Active at

1 (DI 1) 1 - 2

2 (DI 2) 3 - 4

3 (DI 3) 5 - 6

4 (DI 4) 7 - 8

3 (2)

Function and terminal number is mentioned in the actual diagram

5 (DI 5) 9 - 10

6 (DI 6) 11 - 12

7 (DI 7) 13 - 14

8 (DI 8) 15 - 16

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Extension module AK-XM 204A / AK-XM 204B

Function

The module contains 8 relay outputs.

Supply voltage

The supply voltage to the module comes from the previous module in the row.

AK-XM 204B only Override of relay

Eight change-over switches at the front make it possible to override the relay’s function. Either to position OFF or ON. In position Auto the controller carries out the control.

Light-emitting diodes

There are two rows with LED’s. They indicate the following: Left row:

• Voltage supply to the controller

• Communication active with the bottom PC board (red = error)

• Status of outputs DO1 to DO8

Right row: (AK-XM 204B only):

• Override of relays ON = override OFF = no override

AK-XM 204A AK-XM 204B

Fuses

Behind the upper part there is a fuse for each output.

Max. 230 V

AC-1: max. 4 A (ohmic) AC-15: max. 3 A (Inductive)

AK-XM 204B Override of relay

Keep the safety distance!

Low and high voltage must not be connected to the same output group

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Point

Signal Active at

Fans 1

Alarm

O

Point 1 2 3 4 5 6 7 8

Type DO1 DO2 DO3 DO4 DO5 DO6 DO7 DO8

Signal Module Point Terminal Active at

1 (DO 1) 25 - 27

2 (DO 2) 28 - 30

3 (DO 3) 31 - 33

4 (DO 4) 34 -36

5 (DO 5) 37 - 39

6 (DO 6) 40 - 41 - 42

7 (DO 7) 43 - 44 - 45

Function and terminal number is mentioned in the actual diagram

8 (DO 8) 46 - 47 - 48

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Extension module AK-OB 110

Function

The module contains two analog voltage outputs of 0 – 10 V.

Supply voltage

The supply voltage to the module comes from the controller module.

Placing

The module is placed on the PC board in the controller module.

Point

The two outputs have points 24 and 25. They are shown on the earlier page where the controller is also mentioned.

Max. load I < 2.5 mA R > 4 kohm

AO AO1:

Comp.speed

AO2:

Cond.speed

0 - 10 V

Module

Point 24 25

Type AO1 AO2

AO2

AO1

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Extension module AK-OB 101A

Function

The module is a real time clock module with battery backup.

The module can be used in controllers that are not linked up in a data communication unit together with other controllers. The module is used here if the controller needs battery backup for the following functions

• Clock function

• Fixed times for day/night change-over

• Saving of alarm log in case of power failure

• Saving of temperature log in case of power failure

Connection

The module is provided with plug connection.

Placing

The module is placed on the PC board inside the top part.

Point

No point for a clock module to be dened – just connect it.

Working life of the battery

The working life of the battery is several years – even if there are frequent power failures. An alarm is generated when the battery has to be replaced. After the alarm there are still several months of operating hours left in the battery.

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Extension module EKA 163B / EKA 164B

Function

Display of important measurements from the controller, e.g. suction pressure or condensing pressure. Setting of the individual functions can be performed by using the display with control buttons.

Connection

The extension module is connected to the controller module via a cable with plug connections. You have to use one cable per module. The cable is supplied in various lengths.

Both types of display (with or without control buttons) can be connected to either display output A, and B. A = P0 . Suction pressure in °C B = Pc. Condensing pressure in °C

EKA 166 further includes a number of LEDs to make it possible to follow individual functions.

When the controller starts up, the display will show which output is connected. - - 1 = output A, - - 2 = output B, etc.

Placing

The extension module can be placed at a distance of up to 15 m from the controller module.

EKA 163B EKA 164B

EKA 166

Module

Point - -

Type - -

Point

No point has to be dened for a display module – you simply connect it.

Graphic display AK-MMI

Function

Setting and display of values in the controller.

Connection

The display connects to the controller via a cable with plug connections. Use plug RJ45 to connect to the controller; the same plug is also used for service tool AK-ST 500.

Supply voltage

24 V a.c. / d.c. 1.5 VA.

Placing

The display can be placed at a distance of up to 3 m from the controller.

Point

No point has to be dened for a display – you simply connect it.

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Power supply module AK-PS 075

Function

24 V supply for controller.

Supply voltage

230 V a.c or 115 V a.c. (from 100 V a.c. to 240 V a.c.)

Placing

On DIN-rail

Eect

Type Output tension Output current Power

AK-PS 075 24 V d.c. 0.75 A 18 VA

Dimension

Type High Width

AK-PS 075 90 mm 36 mm

Connections

Supply to a controller

AK-PS 075

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Select application

General

Clock function

Clock function and change-over between summer time and winter time are contained in the controller. The clock is zeroset when there is power failure. The clock’s setting is maintained if the controller is linked up in a network with a gateway, a system manager or a clock module can be mounted in the controller.

Start/stop of regulation

Regulation can be started and stopped via the software or via an input on the controller module

Application

40 examples of application are shown in the following: Select the one that ts your system.

Wiring should be done as shown, and the controller should be set for this application.

Regarding speed regulation

An option board has 2 outputs: No. 1 is dedicated to the compressor No. 2 is dedicated to the condenser fans

If you do not use speed control, disregard the shown 0-10 V outputs.

It is only the compressor connection that is shown in all examples, but output 2 can be used for condenser fans at will.

If the speed control needs a start/stop signal, this should be taken from output "Compressor 1" or from "Fan 1".

Forced control

The software contains a forced control option. If an extension module with relay outputs is used, the module’s top part can be with change-over switches – switches that can override the individual relays into either OFF or ON position.

Data communication

The controller module has terminals for LON data communication. The requirements to the installation are described in a separate document.

Number of compressors

2 0 1 21

3 0 5 25

4 0 9 29

5 0 13 33

6 0 17 37

Number of condenser fans

2 2 22

3 3 23

4 4 24

3 6 26

4 7 27

5 8 28

3 10 30

4 11 31

5 12 32

4 14 34

5 15 35

6 16 36

4 18 38

5 19 39

6 20 40

Speed regulation on one compressor

Yes No

Application no.

22 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Application 1 and 21 (for 21 leave out the VSD connection on the option board)

Application 2 and 22 (for 22 leave out the VSD connection on the option board)

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 23

Application 3 and 23 (for 23 leave out the VSD connection on the option board)

Application 4 and 24 (for 24 leave out the VSD connection on the option board)

24 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Application 5 and 25 (for 25 leave out the VSD connection on the option board)

Application 6 and 26 (for 26 leave out the VSD connection on the option board)

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 25

Application 7 and 27 (for 27 leave out the VSD connection on the option board)

Application 8 and 28 (for 28 leave out the VSD connection on the option board)

26 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Application 9 and 29 (for 29 leave out the VSD connection on the option board)

Application 10 and 30 (for 30 leave out the VSD connection on the option board)

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 27

Application 11 and 31 (for 31 leave out the VSD connection on the option board)

Application 12 and 32 (for 32 leave out the VSD connection on the option board)

28 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Application 13 and 33 (for 33 leave out the VSD connection on the option board)

Application 14 and 34 (for 34 leave out the VSD connection on the option board)

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 29

Application 15 and 35 (for 35 leave out the VSD connection on the option board)

Application 16 and 36 (for 36 leave out the VSD connection on the option board)

30 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Application 17 and 37 (for 37 leave out the VSD connection on the option board)

Application 18 and 38 (for 38 leave out the VSD connection on the option board)

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 31

Application 19 and 39 (for 39 leave out the VSD connection on the option board)

Application 20 and 40 (for 40 leave out the VSD connection on the option board)

32 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Ordering

1. Controller

Type Function Language Code no.

AK-PC 710 Controller for capacity control of up to 6 compressors and up to 6 condenser fans

2. Extension modules and survey for inputs and outputs

Type Analog

inputs

For sensors, pressure transmitters etc.

Controller 11 4 4 - - - - -

Extension modules

AK-XM 102A 8 080Z0008

AK-XM 102B 8 080Z0013

AK-XM 204A 8 080Z0011

AK-XM 204B 8 x 080Z0018

AK-OB 110 2 080Z0251

On/O outputs On/o supply voltage

Relay (SPDT)

Solid state Low voltage

(DI signal)

(max. 80 V)

High voltage (max. 260 V)

English, German, French, Dutch, Italian, Spanish

Analog outputs

0-10 V d.c. For override

Module with switches

of relay outputs

080Z0106

Code no.

With screw terminals

3. AK operation and accessories

Type Function Application Code no.

Operation

AK-ST 500 Software for operation of AK controllers AK-operation 080Z0161

- Cable between PC and AK controller AK - Com port 080Z0262

Accessories Power supply module 230 V / 115 V to 24 V

AK-PS 075 18 VA Supply for controller 080Z0053

Accessories External display that can be connected to the controller module. For showing, say, the suction pressure

EKA 163B Display 084B8574

EKA 164B Display with operation buttons 084B8575

EKA 166 Display with operation buttons and LED's for inputs and outputs 084B8578

AK-MMI Graphic display with operation 080G0311

- Cable between EKA display and controller

- Cable between graphic display and controller

Cable between zero modem cable and AK controller / Cable between PDA cable and AK controller

Cable between PC and AK controller AK - USB 080Z0264

AK - RS 232 080Z0261

Length = 2 m 084B7298

Length = 6 m 084B7299

Length = 0.8 m 080G0074

Length = 1.5 m 080G0075

Length = 3 m 080G0076

Accessories Real time clock for use in controllers that require a clock function, but are not wired with data communication.

AK-OB 101A Real time clock with battery backup. To be mounted in an AK controller 080Z0252

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 33

34 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

3. Mounting and wiring

This section describes how the controller:

• Is tted

• Is connected

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 35

Mounting and wiring - continued

Mounting

Mounting of analog output module

1. Lift the top part o the basic module

The basic module must not be connected to voltage.

Press in the plate on the left-hand side of the light-emitting diodes and the plate on the right-hand side for the red address changers. Lift the top part o the basic module.

The analog extension module will supply a signal to the variable frequency drive.

2. Mount the extension module in the basic module

3. Put the top part back on the basic module

36 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Mounting and wiring - continued

Mounting of extension module on the basic module

1. Move the protective cap

Remove the protective cap from the connection plug on the right-hand side of the basic module. Place the cap on the connection plug to the right of the extension module that is to be mounted on the extreme right-hand side of the AK assembly.

2. Assemble the extension module and the basic module

The basic module must not be connected to voltage.

When the two snap catches for the DIN rail mounting are in the open position, the module can be pushed into place on the DIN rail – regardless of where the module is on the row. Disassembly is thus done with the two snap catches in the open position.

The sequence is determined by the shown electrical diagram

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 37

Mounting and wiring - continued

Wiring

Decide during planning which function is to be connected and where this will be.

1. Connect inputs and outputs

See the earlier selected electrical diagram:

2. Connect LON communication network

The installation of the data communication must comply with the requirements set out in document RC8AC.

3. Connect supply voltage

Is 24 V, and the supply must not be used by other controllers or devices. The terminals must not be earthed.

4. Follow light-emitting diodes

When the supply voltage is connected the controller will go through an internal check. The controller will be ready in just under one minute when the light-emitting diode ”Status” starts ashing slowly.

5. When there is a network

Set the address and activate the Service Pin.

6. The controller is now ready to be congured.

Example

The screen on the pressure transmitter cables must only be connected at the end of the controller.

Internal communication between the modules: Quick ash = error Constantly On = error

■ Power

■ Comm

■ DO1 ■ Status

■ DO2 ■ Service Tool

■ DO3 ■ LON

■ DO4

■ DO5 ■ Alarm

■ DO6

■ DO7

■ DO8 ■ Service Pin

Status on output 1-8

Slow ash = OK Quick ash = answer from gateway in 10 min. after network installation Constantly ON = error Constantly OFF = error

External communication

Flash = active alarm/not cancelled Constant ON = Active alarm/cancelled

Network installation

Warning Keep signal cables separate from cables with high voltage.

38 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

4. Conguration and operation

This section describes how the controller:

• Is congured

• Is operated

We have decided to work on the basis of application no. 16, i.e. compressor control with 5 compressors and condenser control with 6 fans. The example is shown overleaf.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 39

Refrigerating plant example

We have decided to describe the setup by means of an example comprising a compressor group and a condenser.

The example is the same as the one given in the "Application no. 16", i.e. the controller is an AK-PC 710 + 3 extension modules.

Compressor pack:

• Refrigerant R134a

• 1 only speed-regulated compressor (30 kW, 30-60 Hz)

• 4 only compressors (15 kW) with working-hour equalisation

• Safety monitoring of each compressor

• Common high-pressure monitoring

• Common low-pressure monitoring

• Po setting -15°C, night displacement 5 K

Condenser:

• 6 fans, step regulation

• Pc regulates based on outdoor temperature Sc3

Receiver:

• Monitoring of liquid level in receiver

Plant room

• Monitoring of temperature in plant room

Safety functions:

• Monitoring of Po, Pc, Sd and superheat on suction line

• Po max = -5°C, Po min = -35°C

• Pc max = 50 °C

• Sd max = 120°C

• SH min = 5 °C, SH max = 35 °C

Other:

• Alarm output used

• External main switch used

• Monitoring of frequency converter (VSD)

For the example shown we use the following modules:

• AK-PC 710 basic module

• AK-XM 204B relay module

• AK-XM 102B digital input module

• AK-OB 110 analog output module

NB!

The capacity of the compressor with speed adjustment should be greater than that of the other compressors. This ensures that there are no "gaps" in the cut in capacity. See chapter 5, Adjustment functions.

There is also an internal main switch as a setting. Both must be “ON” before any adjustment is made.

The used modules is selected in the Design phase.

40 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration via service tool AK-ST 500

Connect PC

PC with the program “Service Tool” is connected to the controller.

The controller must be switched on rst and the LED “Status” must ash before the Service Tool programme is started.

Start Service Tool programme

For connecting and operating the "AK service tool" software, please see the manual for the software.

The rst time the Service Tool is connected to a new version of a controller the start-up of the Service Tool will take longer than usual while information is retrieved from the controller. Time can be followed on the bar at the bottom of the display.

Select the name SUPV and key in the access code.

When the controller is supplied the SUPV access code is 123. When you are logged into the controller an overview of it will always appear.

In this case the overview is empty. This is because the controller has not yet been set up. The red alarm bell at the bottom right tells you that there is an active alarm in the controller. In our case the alarm is due to the fact that the time in the controller has not yet been set.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 41

Conguration - continued

Authorization

1. Go to Conguration menu

Press the orange setup button with the spanner at the bottom of the display.

2. Select Authorization

3. Change setting for the user ‘SUPV‘

When the controller is supplied it has been set with standard authorization for dierent user interfaces. This setting should be changed and adapted to the plant. The changes can be made now or later.

You will use this button again and again whenever you want to get to this display. On the left-hand side are all the functions not shown yet. There will be more here the further into the setup we go.

Press the line Authorization to get to the user setup display.

4. Select username and access code

5. Carry out a new login with the user name and the new access code

Mark the line with the user name SUPV.

Press the button Change

This is where you can select the supervisor for the specic system and a corresponding access code for this person.

In earlier versions of the service tool AK-ST 500 it was possible to select the language in this menu. An updated version of the service tool will be released in the spring of

2009. If the controller is operated with the new version, language selection will happen automatically in connection with the conguration of the service tool. The controller will utilize the same language that is selected in the service tool but only if the controller contains this language. If the language is not contained in the controller, the settings and readings will be shown in English.

To activate the new settings you must carry out a new login to the controller with the new user name and the relevant access code. You will access the login display by pressing the padlock at the top left corner of the display.

42 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration - continued

Unlock the conguration of the controllers

1. Go to Conguration menu

2. Select Lock/Unlock conguration

The controller can only be congured when it is unlocked.

The values can be changed when it is locked, but only for those settings that do not aect the conguration.

3. Select Conguration lock

Press the blue eld with the text Locked

4. Select Unlocked

Select Unlocked and press OK.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 43

Conguration - continued

System setup

1. Go to Conguration menu

2. Select System setup

3. Set system settings

All system settings can be changed by pressing in the blue eld with the setting and then indicating the value of the required setting.

In the rst eld you enter a name for what the controller will be controlling.

When the time is set the PC’s time can be transferred to the controller. When the controller is connected to a network, date and time will automatically be set by the system unit in the network. This also applies to change-over Daylight saving.

If the controller is installed in a network, "automatic acknowledgement of alarms" should be set to "disable" - Hereby the alarm processing and acknowledgement is transferred to the system unit. If the controller is installed without a network, "automatic acknowledgement of alarms" should be set to "enable" - Hereby the controller acknowledges the alarms itself.

44 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration - continued

Set plant type

1. Go to Conguration menu

2. Select plant type

Press the line Select plant type.

3. Set plant type

This setting refers to applications. See page 22.

After conguration of this function, the controller will shut down and restart. After the restart, a large number of settings will have been made. These include the connection points. Continue with the settings and check the values. If you change some of the settings, the new values will.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 45

Conguration - continued

Set control of compressors

1. Go to Conguration menu

2. Select Suction group

3. Set values for the reference

Press the +-button to go on to the

4. Set values for capacity control

The conguration menu in the Service Tool has changed now. It shows the pos-

sible settings for the selected plant type.

In our example we select the settings:

- Suction set point = -15°C

- Night oset value = 5 K. The settings are shown here in the display.

There are several pages, one after the other. The black bar in this eld tells you which of the pages is currently displayed. Move between the pages using the + and - buttons.

In our example we select:

- Refrigerant = R134a

- Equalisation of working hours

- Value for speed regulation Speed regulation can always only be on compressor number 1. The settings are shown here in the display.

Not all compressors can have their speed adjusted. If there is any doubt, contact your compressor supplier.

If you want to know more about the dierent conguration options, they are listed below. The number refers to the number and picture in the column on the left. The screen only shows the settings and readings that are required for a given set-up.

3 - Po-Reference

Reference = set reference + night oset + oset from P0 optimization Setpoint ( -80 to +30°C) Setting of required suction pressure in °C Night Oset (-25 to +25 K) Displacement value for suction pressure in connection with an active night setback signal (set in Kelvin) Changing to night-time operation can be carried out with a signal sent via the data communication, with a signal on the input "night" or via the weekly schedule in the controller. Max reference (-50 to +80 °C) Max. permissible suction pressure reference Min reference (-80 to +25 °C) Min. permissible suction pressure reference

4 - Compressor application Po refrigerant type

Select refrigerant type

Po refrigerant factors K1, K2, K3

Only used if “Po refrigerant type” is set to custom (contact Danfoss for information)

Step control mode

Select coupling pattern for compressors Sequential: Compressors are cut in/out in strict accordance with compressor number (FILO) Cyclic: Runtime equalisation between compressors (FIFO) (same sized compressors) Best t: Compressors are cut in/out in order to make the best possible t to actual load (dierent sized compressors)

Pump down

Select whether a pump down function is required on the last running compressor Pump down limit (-80 to +30 °C) Set the actual pump down limit for the last compressor VSD min speed (0.5 – 60.0 Hz) Min. speed where the compressor must cutout VSD start speed (20.0 – 60.0 Hz) Minimum speed for start of Variable speed drive (Must be set higher than “VSD Min. Speed Hz”) VSD max speed (40.0 – 120.0 Hz) Highest permissible speed for the compressor motor

Load shed limit

Set max capacity limit for load shed Load Shed"

Override limit Po

If the P0 exceeds the value, a time delay is started. If the time delay runs out, the load limit is cancelled

Override delay

Max. time for capacity limit, if P0 is too high Kp Po (0.1 – 10.0) Amplication factor for P0 regulation

Advanced control settings

Select whether the adv. settings must be visible Min. capacity change (0 – 100 %) Set the minimum capacity change needed before the capacity distributor connects or disconnects compressors

Minimize cycling

The control zone may vary for connections and disconnections. See Section 5. Initial start time (15 – 900 s) The time after start-up where the cut-in capacity is limited to the rst compressor step.

46 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration - continued

Press the +-button to go on to the

5. Set values for capacity of the compressors

Press the +-button to go on to the

6. Set values for safe operation

Press the +-button to go on to the

In our example we select:

- Speed-controlled compressor of 30 kW (compressor 1)

- Four compressors of 25 kW The example settings are shown

here in the display.

(For cyclic operation, all one-step compressors have the same size. This is why there is only one setting, but it covers all 4.)

In our example we select:

- Safety limit for discharge temperature = 120°C

- Safety limit for high condensing pressure = 50°C

- Safety limit for low suction pressure = -35°C

- Alarm limit for high suction pressure = -5°C

- Alarm limit for min. and max. superheat, respectively = 5 and 35 K.

5 - Compressors

In this screen the capacity distribution between the compressors is dened. Capacities that need to be set depend upon the “compressor application” and “Step control mode” that has been selected. Nominal capacity (0.0 – 99.9 kW) Set the nominal capacity for the compressor in question. For compressors with variable speed drive the nominal capacity must be set for the mains frequency (50/60 Hz)

6 - Safety Delay time for liquid level alarm

Set the delay time (from the time the signal is lost on the input to the time when the alarm is sent)

Delay time for VSD-alarm

Set the delay time

Temperature alarm limit

Set the threshold value for the temperature alarm

Delay time for the temperature alarm

Set the delay time

Emergency cap. day

The desired cut-in capacity for daily use in the case of emergency operations resulting from error in the suction pressure sensor/ media temperature sensor.

Emergency cap. night

The desired cut-in capacity for night operations in the case of emergency operations resulting from error in the suction pressure sensor/ media temperature sensor.

Sd max limit

Max. value for discharge gas temperature 10 K below the limit, the compressor capacity should be reduced and the entire condenser capacity will be cutin. If the limit is exceeded, the entire compressor capacity will be cutout

Pc Max limit

Maximum value for the condenser pressure in °C 3 K below the limit, the entire condenser capacity will be cutin and the compressor capacity reduced. If the limit is exceeded, the entire compressor capacity will be cutout.

Pc Max delay

Time delay for the alarm Pc max

P0 Min limit

Minimum value for the suction pressure in °C If the limit is reduced, the entire compressor capacity will be cutout.

P0 Max alarm

Alarm limit for high suction pressure P0

P0 Max delay

Time delay before alarm for high suction pressure P0.

Safety restart time

Common time delay before restarting the compressor. (Applicable to the functions: "Sd max. limit", Pc max. limit" and "P0 min. limit).

SH Min alarm

Alarm limit for min. superheat in suction line.

SH Max alarm

Alarm limit for max. superheat in suction line. SH alarm delay Time delay before alarm for min./max. superheat in suction line.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 47

Conguration - continued

7. Set operation time for compressor

Press the +-button to go on to the

8. Set times for safety cutouts

Set min. OFF-time for the compressor relay Set min. ON-time for the compressor relay Set how often the compressor is

allowed to start

If the restrictions overlap, the controller will use the longest restriction time.

7 - Minimum operation times

Congure the operation times here so "unnecessary operation" can be avoided.

Min. OFF time

The time the compressor should be idle before it should start again.

Min. ON time

The time the compressor should operate before it should stop.

Restart time

The lowest time interval between two consecutive starts.

8 - Safety timer Cutout delay

The time delay resulting from drop-out of automated safety measures and until the compressor-error is reported.

Restart delay

Minimum time that a compressor should be OK after a safety cut-out. After this interval it can start again. (An alarm which is triggered by the automatic safety function will be maintained until the restart delay has expired.)

48 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration - continued

Setup control of condenser

1. Go to Conguration menu

2. Select Condenser

3. Set control mode and reference

In our example the condenser pressure is controlled on the basis of the outdoor temperature (oating reference). The settings shown here in the display.

3 - PC reference Reference Mode

Choice of condenser pressure reference Fixed setting: Used if a permanent reference is required = “Setting” Floating: Used if the reference is changed as a function of Sc3 the external temperature signal, the congured "Dimensioning tm K"/"Minimum tm K" and the actual cut in compressor capacity.

Setpoint

Setting of desired condensing pressure in °C. It should also be set when oating references are used. The value is used as a reference if the Sc3 sensor becomes defective.

Min. tm

Minimum average temperature dierence between Sc3 air and Pc condensing temperature when no compressors are in operation.

Dimensioning tm

Dimensioning average temperature dierential between Sc3 air and Pc condensing temperature at maximum load (tm dierence at max load, typically 8-15 K).

Min reference

Min. permitted condenser pressure reference

Max reference

Max. permitted condenser pressure reference

Press the +-button to go on to the

4. Set values for capacity regulation

Used in our example are six stepcontrolled fans. The settings shown here in the display.

4 - Capacity control Capacity control mode

Select control mode for condenser Step: Fans are step-connected via relay outputs Step/speed: The fan capacity is controlled via a combination of speed control and step coupling Speed: The fan capacity is controlled via speed control (frequency converter)

Control type

Choice of control strategy P-band: The fan capacity is regulated via P-band control. The P band is congured as "Proportional band Xp" PI-Control: The fan capacity is regulated by the PI controller.

Capacity curve

Choice of capacity curve type Linear: The same amplication in the entire area Square: Square curve shape, which gives higher amplication at higher loads.

VSD start speed

Minimum speed for start of speed control (Must be congured higher than "VSD Min. Speed %")

VSD min Speed

Minimum speed whereby speed control is cut-out (low load).

Proportional band Xp

Proportional band for P/PI controller

Integration time Tn

Integration time for PI controller

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 49

Conguration - continued

Conguration of inputs and outputs

1. Go to Conguration menu

2. Select I/O conguration

3. Conguration of Digital outputs

Press the +-button to go on to the

4. Setup On/o input functions

The outputs are enabled by On (relay activated)

!!! The alarm is inverted so that there will be an alarm if the supply

voltage to the controller fails.

Select for each input whether the function is to be active when the input is in pos. Closed or Open. Open has been selected here for all the safety circuits. This means that the controller will receive signal under normal operation and register it as a fault if the signal is interrupted.

Press the +-button to go on to the

50 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration - continued

5. Conguration of Analog

outputs

Press the +-button to go on to

the next page

6. Conguration of Analog Input signals

We set up the analog outputs for control of the compressor speed.

We set up the analog inputs for the sensors.

5 - Analog outputs

The possible signals are the following: 0 -10 V 2 – 10 V 0 - 5 V 1 – 5V

6 - Analog inputs

The possible signals are the following: Temperature sensors:

• Pt1000

• PTC 1000

Pressure transmitters:

• AKS 32, -1 – 6 Bar

• AKS 32R, -1 – 6 Bar

• AKS 32, - 1 – 9 Bar

• AKS 32R, -1 – 9 Bar3

• AKS 32, - 1 – 12 Bar

• AKS 32R, -1 – 12 Bar

• AKS 32, - 1 – 20 Bar

• AKS 32R, -1 – 20 Bar

• AKS 32, - 1 – 34 Bar

• AKS 32R, -1 – 34 Bar

• AKS 32, - 1 – 50 Bar

• AKS 32R, -1 – 50 Bar

• AKS 2050, -1 – 59 Bar

• AKS 2050, -1 – 99 Bar

• AKS 2050, -1 – 159 Bar

• Customised ratiometric application: Here, the transmitters min. and max. pressure areas are set (relative pressure reading)

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 51

Conguration - continued

Set alarm priorities

1. Go to Conguration menu

2. Select Alarm priorities

3. Set priorities for Suction group

Very many functions have an alarm connected.

Your choice of functions and settings has connected all the relevant alarms that are current. They will be shown with text in the three pictures.

All alarms that can occur can be set for a given order of priority:

• ”High” is the most important one

• ”Log only” has lowest priority

• ”Disconnected” gives no action

The interdependence between setting and action can be seen in the table.

Setting

High X X X 1

Medium X X 2

Low X X 3

Log only X 4

Disconnected

In our example we select the settings shown here in the display

Log Alarm relay Network AKM- dest.

Press the +-button to go on to the next page

4. Set alarm priorities for condenser

In our example we select the settings shown here in the display

Press the +-button to go on to the next page

52 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration - continued

5. Set alarm priorities for temperature alarm and Digital signals

In our example we select the settings shown here in the display

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 53

Conguration - continued

Lock conguration

1. Go to Conguration menu

2. Select Lock/Unlock conguration

3. Lock Conguration

Press in the eld against Conguration lock.

Select Locked.

Press OK.

The setup of the controller has now been locked. If you subsequently want to make any changes in the controller’s setup, remember rst to unlock the conguration.

The controller will now make a comparison of selected functions and dene inputs and outputs. The result can be seen in the next section where the setup is controlled.

54 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Conguration - continued

Check conguration

1. Go to Conguration menu

2. Select I/O conguration

3. Check conguration of Digital Outputs

This control requires that the setup is locked

(Only when the setup is locked are all settings for in- and outputs activated.)

An error has occurred, if you see the following:

A 0 – 0 next to a dened function. If a setting has reverted to 0-0, you must control the setup again.

Press the +-button to go on to the next page

4. Check conguration of Digital Inputs

Press the +-button to go on to the next page

The error is caused by the two modules connected to the controller being switched.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 55

Conguration - continued

5. Check conguration of Analog Outputs

Press the +-button to go on to the next page

6. Check conguration of Analog Inputs

(If no speed control of the condenser fans is used, the module and point

number can be 0 -0.)

56 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Check of connections

1.Go to Conguration menu

2. Select I/O status and manual

Before the control is started we check that all inputs and outputs have been connected as expected.

This controls requires that the setup is locked

3. Check Digital Outputs

Press the +-button to go on to the next page

4. Check Digital Inputs

By means of the manual control of each output it can be checked whether the output has been correctly connected.

AUTO The output is controlled by the controller

MAN OFF The output is forced to pos. OFF

MAN ON The output is forced to pos ON

Cut out the safety circuit for compressor 1. Check that LED DI1 on the extension module (module 3) goes out.

Check that the value of the alarm for the safety monitoring of compressor 1 changes to ON. The remaining digital inputs are checked in the same way.

Press the +-button to go on to the next page

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Check of connections - continued

5. Check Analog outputs

Set Control of output voltage to manual Press in the Mode eld.

Select MAN.

Press OK.

Press in the Value eld

Select for example 50%.

Press OK.

On the output you can now measure the expected value: In this example 5 volts

6. Put the control of the output voltage back to automatic

Press the +-button to go on to the next page

7. Check Analog inputs

Example of the connection between a dened output signal and a manual set value.

Denition Setting

0 % 50 % 100 %

0 - 10 V 0 V 5 V 10 V

1 - 10 V 1 V 5.5 V 10 V

0 - 5 V 0 V 2.5 V 5 V

2 - 5 V 2 V 3.5 V 5 V

Check that all sensors show sensible values.

In our case we have no value for the suction gas temperature Ss and the two sensors. This may be due to the following:

• The sensor has not been connected.

• The sensor is short-circuited.

• The point or module number has not been set up correctly.

• The conguration is not locked.

58 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Check of settings

1.Go to the overview

2. Select suction group

Before the control starts, we check that all the settings are as they should be.

The overview display will now show one line for each of the general functions. Behind each icon there is a number of displays with the dierent settings. It is all these settings that have to be checked.

3. Move on through all the individual displays for the suction group

Change displays with the +- button. Remember the settings at the bottom of the pages – the ones that can only be seen via the ”Scroll bar”.

4. Safety limits

5. Go back to the overview

The last page contains safety limits and restart times.

6. Select condenser group

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Check of settings - continued

7. Move on through all the individual displays for the condenser group.

Change displays with the +- button. Remember the settings at the bottom of the pages – the ones that can only be seen via the ”Scroll bar”.

8. Safety limits

9. The controller setup has been completed.

The last page contains safety limits and restart times.

60 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Schedule function

1. Go to Conguration menu

2. Select schedule

3. Setup schedule

For your information This setting is not necessary in the example. The signal comes in via DI8.

In other cases where the controller is installed in a network with one system unit, this setting may be made in the system unit which will then transmit a day/night signal to the controller.

This setting can only be used, if the controller stands alone and is tted with a clock module.

Press a weekday and set the time for the day period.

Continue with the other days.

A complete weekly sequence is shown in the display.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 61

Installation in network

1. Set the address (here, for example 3)

Turn the right-hand address switch so that the arrow will point at 3. The arrow of the two other address switches must point at 0.

2. Push the Service Pin

Press down the service pin and keep it down until the Service Pin LED lights up.

The controller has to be remote-monitored via a network. In this net-

work we assign address number 3 to the controller.

The same address must not be used by more than one controller in the

same network.

Requirement to the system unit

The system unit must be a gateway type AKA 245 with software version

6.0 or higher. It is capable of handling up to 119 AK controllers.

3. Wait for answer from the system unit

Depending on the size of the network it may be up to one minute before the controller receives an answer as to whether it has been installed in the network. When it has been installed the Status LED will start to ash faster than normal (once every half second). It will continue with this for about 10 minutes

4. Carry out new login via Service Tool

If the Service Tool was connected to the controller while you installed it in the network, you must carry out a new login to the controller via the Service Tool.

Alternatively, it can be an AK-SM 720. It is capable of handling up to 200 AK controllers.

If there is no answer from the system unit

If the Status LED does not start ashing faster than normal, the controller has not been installed in the network. The reason for this may be one of the following:

The controller has been assigned an address out of range

Address 0 cannot be used.

If the system unit in the network is an AKA 243B Gateway only the addresses between 1 and 10 can be used.

The selected address is already being used by another controller or unit in the network:

The address setting must be changed to another (vacant) address.

The wiring has not been carried out correctly. The termination has not been carried out correctly.

The data communication requirements are described in the document: ”Data communication connections to ADAP-KOOL® Refrigeration Controls” RC8AC.

62 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

First start of control

Check alarms

1. Go to the overview

Press the blue overview button with the compressor and condenser at the bottom left of the display.

2. Go to the Alarm list

Press the blue button with the alarm bell at the bottom of the display.

3. Check active alarms

In our case, we have a series of alarms. We will tidy them up so that we only have those that are relevant.

4. Remove cancelled alarm from the alarm list

Press the red cross to remove cancelled alarms from the alarm list.

5. Check active alarm again

In our case an active alarm remains because the control has stopped. This alarm must be active when control has not started. We are now ready for the startup of control.

Please note that active plant alarms are automatically cancelled when the main switch is in pos. OFF. If active alarms appear when the control is started the reason for these should be found and remedied.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 63

First start of control - continued

Start the control

1. Go to Start/Stop display

Press the blue manual control button at the bottom of the display.

2. Start control

Press in the eld against Main switch. Select ON. Press OK. The controller will now start controlling the compressors and the fans.

Note: Control does not start until both the internal and external switch are “ ON ”.

64 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Manual capacity control

1. Go to overview

2. Select suction group

Press the suction group button for the suction group that is to be controlled manually.

Press the +-button to go on to the next page

3. Set capacity control to manual

If you need to manually adjust the capacity of the compressors, you can use the following procedure:

Press the blue eld against Control mode Select MAN. Press OK.

4. Set capacity in percent

Press in the blue eld against Manual capacity.

Set the capacity to the required percentage. Press OK.

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 65

Setup - continued

Quick setup

It is advantageous for the installer, familiar with the controller, to follow the following procedure:

1. Unlock the conguration

2. Select application (service tool then closes down)

3. Select refrigerant

4. Set the compressor sizes (only if they are dierent)

5. Lock the conguration

6. Check inputs and outputs

7. Turn main switch ON.

66 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Setup - continued

EKA 164, EKA 166 or AKM operation

The controller's functions as can be seen via display EKA 164, EKA 166 and via system software type AKM are shown on the following pages. For access to parameters, press and hold the top button.

EKA-text AKM text R/W Description / Parameter Range Default

Reference

r01 Neutral zone K W Width of neutral zone for compressor control 0,1 – 20,0 K 6,0 K

r04 Po sensor adjust W Calibration of Po sensor -10,0 - 10,0 Bar 0,0 bar

r12 Main switch W "Main switch for start/stop of control

ON: Normal control OFF: Control is stopped"

r13 Night oset K W Displacement value for suction pressure in con¬nection with an active

night setback signal (set in Kelvin)

r23 Po setpoint °C W Setting of required reference pressure in °C -80,0 °C - 30,0 °C -15,0 °C

r24 Comp. ctrl. Ref. °C R Actual reference temp. for compressor capacity (incl. external reference

signal, if any)

r25 Max reference °C W Max. permissible suction pressure reference -50,0 °C - 80,0 °C 80,0 °C

r26 Min Reference °C W Min. permissible suction pressure reference -80,0 °C - 25,0 °C -80,0 °C

r27 Night setback R Actual status of night setback ON/OFF

r28 Pc setpoint °C W Setting of desired condensing pressure in °C -25,0 °C - 90,0 °C 35,0 °C

r29 Cond. ctrl. Ref. °C R Reference for condenser in °C

r30 Min Reference °C W Min. permitted condenser pressure reference -25,0 °C - 100,0 °C 10,0 °C

r31 Max Reference °C W Max. permitted condenser pressure reference -25,0 °C - 100,0 °C 50,0 °C

r32 Pc sensor adjust W Calibration of Pc sensor -10,0 - 10,0 Bar 0,0 bar

r33 Pc Reference mode W "Choice of condenser pressure reference

0: Reference = Pc setpoint 1: The reference is changed as a function of Sc3 the external temperature signal"

r35 Dimensioning tm K W Dimensioning mean temperature dierential between Sc3 air and Pc

condensing temperature at maximum load (compressor capacity = 100%). Dimensioning temp dierence at max load, typically 8-15 K).

r56 Min tm K W Minimum mean temperature dierence between Sc3 air and Pc condens-

ing temperature at no load (Compressor capacity = 0%)

r57 Po °C R Suction pressure in °C. (Measured with the Po pressure transmitter)

Capacity control

c08 Step mode W "Select coupling pattern for compressors

0: Sequential: Compressors are cut in/out in strict ac¬cordance with compressor number (FILO) 2: Cyclic: Runtime equalisation between compressors (FIFO) 3: Best t: Compressors are cut in/out in order to make the best possible t to actual load"

c10 + Zone band K W Width of “+ Zone” above neutral zone 0,1 – 20,0 K 4,0 K

c11 + Zone delay s W Integrationtime in ”+ Zone” 10,0 – 900,0 s 300 s

c12 ++ Zone delay s W Integrationtime in ”++ Zone” 10,0 – 900,0 s 300 s

c13 - Zone band K W Width of “- Zone” below neutral zone 0,1 – 20,0 K 3,0 K

c14 - Zone delay s W Integrationtime in ”- Zone” 10,0 – 900,0 s 150 s

c15 -- Zone delay s W Integrationtime in ”-- Zone” 1,0 – 300,0 s 30 s

c16 Comp. application R Readout compressor combinations 0: Single step only

c29 No. of fans R Read out number of fans 0 - 6 0

c31 Manual capacity % W "Manual setting of compressor capacity

The value is in % of total capacity controlled by the controller"

c32 Cap. control mode W Select whether capacity control is stopped, in manual control or controlled

via PI controller

c33 Po pump down limit°C W Set the actual pump down limit for the last compressor -80,0 °C - 30,0 °C -40,0 °C

c35 Load shed limit 1 W Set max compressor capacity limit for load shed input 0 - 100% 100%

"ON: Normal control OFF: Control is stopped"

-25,0 - 25,0 K 0,0 K

"0: Pc setpoint 1: Floating"

0,0 - 25,0 K 15,0 K

0,0 - 20,0 K 6,0 K

"0: Sequential 2: Cyclic 3: Best t "

4: 1 x variable speed + single step

0 - 100% 0%

0: Manual control 1: OFF 2: Auto

OFF

1: Floating

2: Cyclic

0: Single step only

2: Auto

AK-PC 710 Capacity controller RS8FT502 © Danfoss 08-2015 67

Setup - continued

c36 Override limit Po W Any load below the limit value is freely permitted. If the suction pressure

Po exceeds the value, a time delay is started. If the time delay runs out, the load limit is cancelled

c37 Override delay 1 min W Max. time for capacity limit, if Po is too high 0 - 240 min 10 min

c38 Pump down W Select whether a pump down function is required on the last running

compressor

c39 Initial start time W The time after start-up where the cut-in capacity is limited to the rst

compressor step.

c40 Compressor 1 size W "Set the nominal capacity for the compressor in question.

For compressors with variable speed drive the nominal capacity must be set for the mains frequency (50/60 Hz) Set the nominal capacity for the compressor in question."

c41 Compressor 2 size W Set the nominal capacity for the compressor in question. 0,0 - 99,9 kW 0 kW

c42 Compressor 3 size W Set the nominal capacity for the compressor in question. 0,0 - 99,9 kW 0 kW

c43 Compressor 4 size W Set the nominal capacity for the compressor in question. 0,0 - 99,9 kW 0 kW

c44 Compressor 5 size W Set the nominal capacity for the compressor in question. 0,0 - 99,9 kW 0 kW

c45 Compressor 6 size W Set the nominal capacity for the compressor in question. 0,0 - 99,9 kW 0 kW

c46 VSD Min speed Hz W Min. speed where the compressor must cutout 0,5 Hz 60,0 Hz

c47 VSD Start speed Hz W Minimum speed for start of Variable speed drive (Must be set higher than

“VSD Min. Speed Hz”)

c48 VSD Max speed Hz W Highest permissible speed for the compressor motor 40,0 Hz 120,0 Hz

c49 Emergency cap day% W The desired cut-in capacity for daily use in the case of emergency opera-

tions resulting from error in the suction pressure sensor/ media temperature sensor

c50 Emergency cap. night% W The desired cut-in capacity for night operations in the case of emergency

operations resulting from error in the suction pressure sensor/ media temperature sensor.

Compressor timers

c51 Comp. 1 Min. ON-time W Minimum duration of ON period 0 - 60 min 0 min

c52 Comp. 2 Min. ON-time W Minimum duration of ON period 0 - 60 min 0 min

c53 Comp. 3 Min. ON-time W Minimum duration of ON period 0 - 60 min 0 min

c54 Comp. 4 Min. ON-time W Minimum duration of ON period 0 - 60 min 0 min

c55 Comp. 5 Min. ON-time W Minimum duration of ON period 0 - 60 min 0 min

c56 Comp. 6 Min. ON-time W Minimum duration of ON period 0 - 60 min 0 min

c57 Comp. 1 Min. OFF-time W Minimum duration of OFF periode 0 - 30 min 0 min

c58 Comp. 2 Min. OFF-time W Minimum duration of OFF periode 0 - 30 min 0 min

c59 Comp. 3 Min. OFF-time W Minimum duration of OFF periode 0 - 30 min 0 min

c60 Comp. 4 Min. OFF-time W Minimum duration of OFF periode 0 - 30 min 0 min

c61 Comp. 5 Min. OFF-time W Minimum duration of OFF periode 0 - 30 min 0 min

c62 Comp. 6 Min. OFF-time W Minimum duration of OFF periode 0 - 30 min 0 min

c63 Comp. 1 Recycle time W Minimum period between two successive compressor starts 1 - 60 min 6 min

c64 Comp. 2 Recycle time W Minimum period between two successive compressor starts 1 - 60 min 6 min

c65 Comp. 3 Recycle time W Minimum period between two successive compressor starts 1 - 60 min 6 min

c66 Comp. 4 Recycle time W Minimum period between two successive compressor starts 1 - 60 min 6 min

c67 Comp. 5 Recycle time W Minimum period between two successive compressor starts 1 - 60 min 6 min

c68 Comp. 6 Recycle time W Minimum period between two successive compressor starts 1 - 60 min 6 min

Neutral zone control

n04 Xp P-band K W Proportional band for condenser P/PI controller 0,0 - 100,0 K 10,0 K

n05 Tn Integr. time s W Integration time for condenser PI controller 30 - 600 sec 180 sec

n20 Kp Po W Amplication factor for compressor capacity control 0,1 - 10,0 2

n52 Control mode W "0: MAN (The condenser capacity will be controlled manually)

1: OFF (The capacity control will be stopped) 2: AUTO (The capacity is controlled by the PI controller)"

n53 Manual capacity % W Manual setting of condenser capacity 0 - 100% 0%

n54 VSD Start speed % W Condenser minimum speed for start of speed control (Must be congured

higher than "VSD Min. Speed %")

n55 VSD Min. speed % W Condenser minimum speed whereby speed control is cut-out (low load). 0,0 - 40,0 % 10,0%

-50,0 °C - 80,0 °C 80,0 °C

0: No 1: Yes

0 - 900 sec 120 sec

0,0 - 99,9 kW 0 kW

20,0 Hz 60,0 Hz

0 - 100% 50%

100% 25%

0: Manual control 1: OFF 2: Auto

0,0 - 40,0 % 20,0%

0: No

2: Auto

68 Capacity controller RS8FT502 © Danfoss 08-2015 AK-PC 710

Setup - continued

n94 Step/speed W "Select control mode for condenser

0: Step: Fans are step-connected via relay outputs 1: Step/speed: The fan capacity is controlled via a combination of speed control and step coupling 2: Speed: The fan capacity is controlled via speed control (frequency converter)"

n95 Control type W "Choice of control strategy for condenser

0: P-band: The fan capacity is regulated via P-band control. The P band is congured as ""Proportional band Xp"" 1: PI-Control: The fan capacity is regulated by the PI controller"

Alarm/Safety Settings

A03 Saux 1 High alarm del W Alarm delay for high Saux temperature 0 - 360 min 5 min

A10 Po Max alarm °C W Alarm limit for high suction pressure Po -30,0 °C - 100,0 °C 100,0 °C

A11 Po Min limit °C W "Minimum value for the suction pressure in °C

If the limit is reduced, the entire compressor capacity will be cutout."

A28 Low liquid level delay W Time delay for the low liquid level alarm 0 - 360 min 5 min

A30 Pc Max limit °C W "Maximum value for the condenser pressure in °C

3 K below the limit, the entire condenser capacity will be cutin and the compressor capacity reduced. If the limit is exceeded, the entire compressor capacity will be cutout."

A35 Saux 1 High alarm °C W High temp. alarm limit for Saux sensor -80,0 °C - 120,0 °C 120,0 °C

A44 Po Max delay m W Time delay before alarm for high suction pressure P0. 0 - 240 min 5 min

A45 Pc Max alarm delay m W Time delay for the alarm Pc max 0 - 240 min 0 min

A58 Sd max limit°C W "Max. value for discharge gas temperature

10 K below the limit, the compressor capacity should be reduced and the entire condenser capacity will be cutin. If the limit is exceeded, the entire compressor capacity will be cutout"

A59 SH min alarm K W Alarm limit for min. superheat in suction line. 0,0 - 20,0 K 0,0 K

A60 SH max alarm K W Alarm limit for max. superheat in suction line. 20,0 - 80,0 K 80,0 K

A61 SH alarm delay W Time delay before alarm for min./max. superheat in suction line. 0 - 60 min 5 min

A62 Safety restart time m W "Common time delay before restarting the compressor.

(Applicable to the functions: ""Sd max. limit"", Pc max. limit"" and ""P0 min. limit)."

A64 VSDcutoutDel W Time delay before VSD alarm 0-360 min 5 min

Misceallanous

o12 Mains frequency W Select frequency of the power supply 0: 50 Hz

o19 No. of compressors R Readout number of compressors 0 - 6 0

o21 Po sensor W Select sensor type for Po

0: User dened, 1=AKS32-6, 2=AKS32R-6, 4=AKS32-9, 5=AKS32R-9, 7=AKS32-12, 8=AKS32R-12, 10=AKS32-20, 11=AKS32R-20, 13=AKS32-34, 14=AKS32R-34, 16=AKS32-50, 17=AKS32R-50, 31=AKS2050-59, 32=AKS2050-99, 33=AKS 2050-159

o23 Comp. 1 Runtime W Compressor’s total run time in hours 0 - 999999 h 0 h

o24 Comp. 2 Runtime W Compressor’s total run time in hours 0 - 999999 h 0 h

o25 Comp. 3 Runtime W Compressor’s total run time in hours 0 - 999999 h 0 h

o26 Comp. 4 Runtime W Compressor’s total run time in hours 0 - 999999 h 0 h

o30 Refrigerant type W Select refrigerant type for Po

1=R12, 2=R22, 3=134a, 4=R502, 5=R717, 6=R13, 7=R13b1, 8=R23, 9=R500, 10=R503, 11=R114, 12=R142b, 13=User def., 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, 36=XP10, 37=R407F

o48 Pc sensor W Select sensor type for Po

o50 Comp. 5 Runtime W Compressor’s total run time in hours 0 - 999999 h 0 h

o51 Comp. 6 Runtime W Compressor’s total run time in hours 0 - 999999 h 0 h

o61 Quick setup select W "Select a predened application.

Gives a choice between a number of prede¬ned applicatons, which at the same time determine the wiring connection points. (see manual for further details)"

o93 Conguration lock W The controller can only be congured when it is unlocked. 0: Unlocked

P40 Auto ack alarms W Select whether the controller should auto acknowledge alarms. In stand

alone applications it should be set to Enabled

0: Step control 1: Step/Speed 2: Speed

0: P-band control 1: PI control

-120,0 °C - 30,0 °C -40,0 °C

-30,0 °C - 100,0 °C 50,0 °C

-0,0 °C - 150,0 °C 80,0 °C

0 - 60 min 5 min

1: 60 Hz

0-33 8

0: None 37

0-33 14

See documenation for quick selections

1: Locked

0: Enabled 1: Disabled

0: Step

1: PI control

0: 50 Hz

0: None selected

0: Unlocked

1: Disabled

Setup - continued

Service

u01 Pc °C R Condensing pressure in °C. (measured with the Pc pressure transmitter)

u03 Saux 1 °C R Air temp Saux temperature in °C

u10 Lowliquid level alarm R Actual status of low liquid alarm ON/OFF

u21 Suction superheat K R Superheat in suction line

u37 Common fan safety R Actual status of common fan safety input ON/OFF

u44 Sc3 Air on °C R Outdoor temperature in °C measured with Sc3 temperature sensor

u48 Condenser status R Actual control status of condenser

u49 Cond. Cap % R Cut-in condenser capacity in % (of total capacity) 0-100%

u50 Request Cond. Cap % R Reference for condenser capacity 0-100%

u51 Suction status R Actual control status of suction group

u52 Compressor Cap % R Cut-in compressor capacity in % (of total capacity) 0-100%

u53 Request Comp. Cap % R Reference for compressor capacity (deviations may be due to time delays) 0-100%

u54 Sd discharge gas °C R Discharge gas temperature in °C

u55 Ss suction gas °C R Suction gas temperature in °C

u87 Load shed input 1 R Actual status on Load shed input ON/OFF

u88 HP common safety R Actual status of common HP safety input for all compressors ON/OFF

u89 LP common safety R Actual status of common LP safety input for all compressors ON/OFF

U12 Actual setup R Actual selected quic setup See documenation

U13 Injection ON R Status of the “Injection ON” function ON/OFF

0=Power up 1=Stopped 2=Manual 3=Alarm 4=Restart 5=Standby 10=Full loaded 11=Running

for quick selections

Setup - continued

Alarms

A02 Low suction pressure Po Minimum safety limit for suction pressore Po has been violated

A11 Refrigerant A not selected Refrigerant has not been selected

A17 High Cond. pressure Pc High safety limit for condensing pressure Pc has been violated

A19 Comp. 1 safety cutout Compressor no. 1 has been cut out on safety input

A20 Comp. 2 safety cutout Compressor no. 2 has been cut out on safety input

A21 Comp. 3 safety cutout Compressor no. 3 has been cut out on safety input

A22 Comp. 4 safety cutout Compressor no. 4 has been cut out on safety input

A23 Comp. 5 safety cutout Compressor no. 5 has been cut out on safety input

A24 Comp. 6 safety cutout Compressor no. 6 has been cut out on safety input

A28 Low liquid level Low liquid level alarm input has been activated

A31 LP common safety Compressors have been cut out on common LP safety input

A32 HP common safety Compressors have been cut out on common HP safety input

A34 Common fan safety Common fan safety input has been activated

A35 Air room High temp. The temperature measured by Saux 1 sensor is too high

A45 Main switch Control has been stopped via the setting ”Main Switch” = OFF or via the

A85 High discharge temp. Sd Safety limit for discharge temperature has been exceeded

A86 High superheat Ss Superheat in suction line too high

A87 Low superheat Ss Superheat in suction line too low

A88 System Critical excep-

tion #1

A89 Manual DI………. An input has been set in manual control mode via the service tool software

A93 VSD safety cutout VSD alarm input has been activated

E02 Po sensor error Pressure transmitter signal from Po defective

Ss sensor error Temperature signal from Ss suction gas temp. defective

Sd sensor error Temperature signal from Sd discharge gas temp. Sd defective

Pc sensor error Pressure transmitter signal from Pc defective

Sc3 sensor error Temperature signal from Sc3 air on condenser defective

Saux1 sensor error Signal from extra temp. sensor Saux1 defective

System alarm exception #1

Alarm Destination disabled

Alarm Route failure Alarms can not be send to the alarm receiver – check the communication

Alarm Router full The internal buer for alarm has been exceeded. This can happen if the

Device is restarting Restart of controller after a ash update of the software

Common IO Alarm A communication problem has arised between the controller and the

Manual DO……… An output has been set in manual control mode via the service tool

- - 1 Initiation. Display is connected to output A. (- - 2 = output B, etc.)

external main switch input

A critical system fault has arisen – the controller needs to be exchanged

A minor system fault has arisen – power OFF/ON the controller

When this alarm is active the alarm transmission to the alarm receiver has been disabled. When the alarm is cancelled the alarm transmission is enabled

to controller/alarm receiver

alarm transmission to the alarm receiver is interrupted – see above.

extension modules – the problem should be checked immediately

software

5. Regulating functions

This section describes how the dierent functions work

Suction group

Controlling sensor

The capacity distributor can regulate according to the suction pressure P0.

Night displacement

The function is used to change the suction pressure reference for night time operation as an energy saving function. With this function the reference can be displaced by up to 25 K in positive or negative direction. (When you displace to a higher suction pressure, a positive value is set). Displacement can be activated in three ways:

• Signal on an input

• From a master gateway’s override function

• Internal time schedule

The “night displacement” function should not be used when regulation with the override function “P0-optimisation” is performed. (Here the override function will itself adapt the suction pressure to the max. permissible).

If a short change in the suction pressure is needed (for example, up to 15 minutes in connection with defrosting) the functions can be applied. Here the PO-optimisation will not have time to compensate for the change.

Handling of sensor error

An error in the sensor will mean that regulation continues with 50% cutin in daily operation and 25% cut-in at night, but for a minimum of one step.

Reference

P0Ref = P0 setting + P0 optimization + night displacement

P0 setting

A basic value for the suction pressure is set.

P0 optimization

This function displaces the reference so that regulation will not take place with a lower suction pressure than required. The function cooperates with controllers on the individual refrigeration appliances and a system manager. The system manager obtains data from the individual regulations and adapts the suction pressure to the optimum energy level. The function is described in the manual for the System manager. With this function you can read which appliance is most heavily loaded at the moment as well as the displacement allowed for the suction pressure reference.

Limitation of reference

To safeguard yourself against a too high or too low regulation reference, a limitation of the reference must be set.

P0 ref

Max.

Min.

Forced operation of the compressor capacity in the suction group

A forced operation of the capacity can be carried out which disregards the normal regulation. Depending on the selected form of forced operation, the safety functions will be cancelled.

Forced operation via overload of requested capacity

The control is set to manual and the desired capacity is set in % of the possible compressor capacity.

Forced operation via overload of digital outlets

The individual outputs can be set to MAN ON or MAN OFF in the software. The control function disregards this but an alarm is sent out that the outlet is being overridden.

Forced operation via change-over switches

If the forced operation is done with the switch-over on the front of an expansion model, this is not registered by the control function and no alarm is sounded. The controller continues to run and couples with the other relays.

Capacity control of compressors

PI-control and control zones

AK-PC 710 can control up to 6 compressors. One of the compressors can be equipped with speed regulation.

In the “- Zone” and “-- Zone” the controller will normally decrease the requested capacity as the suction pressure is below the set point. But if the suction pressure is increasing very fast the requested capacity might increase also in these zones.

The calculation of the requested compressor capacity takes place on the basis of a PI control, but the set up is carried out in the same way as for a neutral zone which is divided into 5 dierent control zones as shown in below sketch.

Suction pressure P0

The width of some of the zones can be set via the settings “+ Zone K”, “NZ K” and “- Zone K”. Furthermore it is possible to adjust zone timers which is equal to the Tn integration time for the PI controller whenever the suction pressure is in the zone in question (please see sketch above).

By setting a zone timer to a higher value will make the PI controller slower in this zone and by setting the zone timer lower will make the PI controller faster in this zone.

Change capacity

The controller will cutin or cutout capacity based on these basic rules:

Increase capacity: The capacity distributor will start extra compressor capacity as soon as the requested capacity has increased to a value, which allows the next compressor step to start. Referring to below example - a compressor step is added as soon as there is “Room” for this compressor step below the requested capacity curve.

Decrease capacity: The capacity distributor will stop compressor capacity as soon as the requested capacity has decreased to a value, which allows the next compressor to stop. Referring to below example - a compressor step is stopped as soon as there is no more “Room” for this compressor step above the requested capacity curve.

Example: 4 compressor of equal size - The capacity curve will look like this

The amplication factor Kp is adjusted as parameter ”Kp Po” In the neutral zone the controller is only allowed to increase or decrease the capacity by means of speed control and/or switching of unloader valves. In the other zones the controller is also allowed to increase/ decrease capacity by means of starting and stopping compressors.

Operation time rst step

At start-up the refrigeration system must have time to be stable before the PI controller takes over the control. For this purpose at start-up of a plant a limitation is made of the capacity so that only the rst capacity step will cutin after a set period (to be set via "runtime rst step").

Requested capacity

The readout “Requested capacity” is the output from the PI controller and it shows the actual requested compressor capacity by the PI controller. The rate of change in the requested capacity depends upon in which zone the pressure is and whether the pressure is stable or whether it is constantly changing.

The Integrator is looking at the deviation between the set point and the current pressure only and increases/reduces the requested capacity correspondingly. The amplication factor Kp on the other hand only looks at the temporary pressure changes.

Cut-out of the last compressor stage: Normally, the last compressor step will only be cut-out when the required capacity is 0% and the suction pressure is at "-Zone" or in "—Zone"

Pump down function:

To avoid too many compressor starts/stops with low load, it is possible to dene a pump down function for the last compressor.

If the pump down function is used, the compressors will be cutout when the actual suction pressure is down to the congured pump down limit.

Note that the congured pump down limit should be set higher than the congured safety limit for low suction pressure "Min Po".

In the “+ Zone” and “++ Zone” the controller will normally increase the requested capacity as the suction pressure is above the set point. But if the suction pressure is decreasing very fast the requested capacity might decrease also in these zones.

Dynamic extension of the neutral zone

All refrigeration systems have a dynamic response time when starting and stopping compressors. In order to avoid that the controller will start/stop compressors shortly after each other, the controller must be allowed some extra time after a compressor start/stop to see the eect of the previous change in running capacity.

In order to achieve this, a dynamic extension of the zones is added.

Capacity distribution methods

The capacity distributor can work based on 3 distribution principles.

Coupling pattern – sequential operation:

The compressors are cut in and cut-out following the “First in, Last out” (FILO) principle in accordance with the sequence dened in the set-up. Any speed-regulated compressors are used to close capacity gaps.

The zones will be extended for a short period of time when starting or stopping a compressor. By extending the zones the PI controller will be slowed down in a short period of time after a change in compressor capacity.

The amplitude of the zone extension depends upon the actual running compressor capacity and upon the size of the compressor step which is being stopped/started. The amplitude of the zone extension is bigger when running with low compressor capacity and when starting/stopping big compressor capacity steps. However the time period for the zone extension is constant – after a xed time period after a compressor start/stop the dynamic zone extension is reduced to 0. Via the “Minimize number of couplings” setting it is possible to inuence how big the amplitude of the dynamic zone extension should be in order to minimize the cycling of the compressors. By setting “Minimize number of couplings” to “No reduction” there will be no dynamic extension of the zones. By setting “Minimize number of couplings” to “Low”, “Medium” or “High” the dynamic extension of the zones will be activated. The amplitude of the zone extension will be highest when “Minimize number of couplings” is set to “High”. Please refer to the next sketch which shows an example with 6 compressor steps and with “Minimize number of couplings” set to “High”. Please also note that the dynamic extension of the zones is highest at low compressor capacity.

“Minimize number of couplings” = “High”

Timer restrictions If a compressor is prevented from starting because it “hangs” on the re-start timer, this step is not replaced by another compressor but the step switch waits until the timer has lapsed.

Safety cutout If on the other hand there is a safety switch on this compressor, this is excluded and the step switch immediately selects the following step in the sequence.

Coupling pattern – Cyclical operation:

This principle is used if all compressors are of the same type and size. The compressor cuts-in and cuts-out in accordance with the "First In First Out" principle (FIFO) to equalise operating hours between the compressors. Speed-regulated compressors will always be cut in rst, and the variable capacity is used to ll capacity gaps between the subsequent steps.

Timer restrictions and safety cut outs If a compressor is prevented from starting because it is “hanging” on the restart timer or is safety cut out, this step is replaced by another compressor.

Operating time equalisation

The operating hour equalizing is carried out between compressors of the same type with the same total capacity.

-At the dierent startups the compressor with the lowest number of operating hours will be started rst.

- At the dierent stops the compressor with the highest number of operating hours will be stopped rst.

- For compressors with several steps, the operating time equalizing is carried out between the compressors’ main steps.

Coupling pattern – Best t operation

This principle is used if the compressors are of dierent sizes. The capacity distributor will cut-in or cut-out the compressor capacity in order to ensure the least possible capacity jump. Speed-regulated compressors will always be cut in rst, and the variable capacity will be used to ll capacity gaps between the subsequent steps.

Timer restrictions and safety cut outs

Actual band

As a consequence of the dynamic extension of the zones the suction pressure might very well change zone for a period of time when the controller is starting/stopping a compressor i.e. the suction pressure is in the +Zone, but as the controller starts a compressor, the zones are extended for a period of time and during this period of time the suction pressure will be in the NZ.

In the controller the readout “Actual band” will show in which zone the PI controller is operating – this includes the extension of the zones.

If a compressor is prevented from starting because it is “hanging” on the restart timer or is safety-cut out, this step is replaced by another compressor or another combination.

Minimum capacity change To prevent the capacity distributor from selecting a new compressor combination (cut-out and cut-in compressors) due to a small change in capacity requirements, it is possible to set a minimum change in capacity requirement that will operate before the capacity distributor changes to a new compressor combination.

Power pack types – compressor combinations

The controller is able to control power packs with up to 6 compressors of various types:

- One speed controlled compressor

- Single step compressors – piston or scroll

The chart below shows the compressor combination which the controller is capable of controlling. The chart also shows which coupling pattern can be set for the individual compressor combinations.

Combination Description Coupling

One-step compressors. *1 x x x 21-40

pattern

Sequence

Cyclical

Application

Best t

*1) For a cyclical coupling pattern, the one-step compressors must be the same size. *2) Speed-regulated compressors can have dierent sizes in relation to subsequent

compressors.

A speed-regulated compressor combined with one-step compressors. *1 and *2

x x x 1-20

In appendix A there is a more detailed description of the coupling patterns for the individual compressor applications with associated examples.

The following is a description of some general rules for handling speed-regulated compressor.

Speed control compressors:

The controller is able to use speed control on the leading compressor in dierent compressor combinations. The variable part of the speed controlled compressor is used to ll in capacity gaps of the following compressor steps.

General regarding handling:

One of the dened capacity steps for the compressor regulation may be connected to a speed control unit that may be a frequency converter type VLT, for example.

An output is connected to the frequency converter’s ON/OFF input and at the same time an analog output ”AO” is connected to the frequency converter’s analog input. The ON/OFF signal will start and stop the frequency converter and the analog signal will indicate the speed. It is only the compressor dened as compressor 1 that can be speed controlled.

When the step is in operation it will consist of a xed capacity and a variable capacity. The xed capacity will be the one that corresponding to the mentioned min. speed and the variable one will lie between the min. and max. speed. To obtain the best regulation the variable capacity must be bigger than the subsequent capacity steps it has to cover during the regulation. If there are major short-term variations in the plant’s capacity requirement it will increase the demand for variable capacity.

This is how you cut the step in and out:

Controlling – increasing capacity If the need for capacity becomes larger than “Max. Speed” then the subsequent compressor step will be cut-in. At the same time, the speed on the capacity step will be reduced so the capacity is reduced with a size that corresponds to exactly the cut-in compressor step. Thereby a completely "frictionless" transition is achieved without capacity holes (refer also to sketch).

Controlling – decreasing capacity If the capacity requirement becomes less than “Min. speed” then the subsequent compressor step will be cut-out. At the same time, the speed on the capacity step is increased so the capacity is increased with a size that corresponds to exactly the cut-out compressor step.

Cut-out The capacity step will be cut-out when the compressor has reached “Min. Speed” and the requested capacity has dropped to 1%.

Timer restriction on speed controlled compressor If a speed controlled compressor is not allowed to start due to a timer restriction, no other compressor is allowed to start. When the timer restriction has expired the speed controlled compressor will start.

Cutin The speed-controlled compressor will always be the rst to start and the last to stop. The frequency converter will be started when a capacity requirement corresponding to the mentioned ”Start speed” arises (the relay output changes to ON and the analog output is supplied with a voltage corresponding to this speed). It is now up to the frequency converter to bring the speed up to ”Start speed”. The capacity step will now be cut in and the required capacity determined by the controller. The start speed always ought to be set so high that a fast lubrication of the compressor is obtained during the start.

Safety cutout on speed controlled compressor If the speed controlled compressor is cutout on safety other compressors are allowed to start. As soon as the speed controlled compressor is ready to start it will be the rst compressor to start.

As mentioned before the variable part of the speed capacity should be bigger than the capacity of the following compressor steps in order to achieve a capacity curve without “holes”. In order to illustrate how the speed control will react at dierent pack combinations a couple of examples will be given here:

a) Variable capacity bigger than following compressor steps:

When the variable part of the speed controlled compressor is bigger than the following compressors there will be no “holes” in the capacity curve. Example: 1 speed controlled compressor with a nominal capacity at 50Hz of 10kw - Variable speed range 30 – 90Hz 2 one step compressors of 10 kW

Fixed capacity = 30 HZ / 50 HZ x 10 kW = 6 kW Variable capacity = 60 HZ / 50Hz x 10 kW = 12 kW

The capacity curve will look like this:

As the variable part of the speed controlled compressor is bigger than the following compressor steps, the capacity curve will be without holes.

1) The speed controlled compressor will be cutin when the requested capacity has reached the start speed capacity.

2) The speed controlled compressor will increase speed until it reaches max speed at a capacity of 18 kw.

3) The one step compressor C2 of 10 kW is cut in and the speed on C1 is reduced too so that it corresponds to 8kW (40Hz)

4) The speed controlled compressor will increase speed until the total capacity reaches 28 kw at max speed

5) The one step compressor C3 of 10kW is cut in and the speed on C1 is reduced too so that it corresponds to 8kW (40Hz)

6) The speed controlled compressor will increase speed until the total capacity reaches 38 kw at max speed

7) When reducing capacity the one step compressors will be cut out when the speed on C1 is at minimum

As the variable part of the speed controlled compressor is smaller than the following compressor steps the capacity curve will have some holes that can not be lled out by the variable capacity.

1) The speed controlled compressor will be cutin when the requested capacity has reached the start speed capacity.

2) The speed controlled compressor will increase speed until it reaches max speed at a capacity of 20 kw.

3) The speed controlled compressor will stay at max speed until the requested capacity has increased to 30 kW.

4) The one step compressor C2 of 20 kW is cut in and the speed on C1 is reduced to min. so that it corresponds to 10kW (25Hz). Total capacity = 30 kW.

5) The speed controlled compressor will increase speed until the total capacity reaches 40 kW at max speed

6) The speed controlled compressor will stay at max speed until the requested capacity has increased to 50 kW.

7) The one step compressor C3 of 20kW is cut in and the speed on C1 is reduced to min. so that it corresponds to 10kW (25Hz). Total capacity = 50 kW

8) The speed controlled compressor will increase speed until the total capacity reaches 60 kw at max speed

9) When reducing capacity the one step compressors will be cut out when the speed on C1 is at minimum speed.

Compressor timers

Time delays for cutins and cutouts

To protect the compressor against frequent restarts three time delays can be put in.

- A minimum time to run from a compressor’s startup and until it

may be restarted.

- A minimum time (ON-time) for the compressor to operate before

it may be stopped again.

- A minimum OFF time to run from a compressor stops and until it

may be restarted

When unloaders are cut in and out, the time delays will not be used.

b) Variable part smaller than following compressor steps:

If the variable part of the speed controlled compressor is smaller than the following compressors there will be “holes” in the capacity curve.

Example: 1 speed controlled compressor with a nominal capacity at 50Hz of 20kw - Variable speed range 25 – 50Hz 2 one step compressors of 20 kW Fixed capacity = 25 HZ / 50 HZ x 20 kW = 10 kW Variable capacity = 25 HZ / 50Hz x 20 kW = 10 kW

The capacity curve will look like this:

Timer

The operating time of a compressor motor is registered continuously. You can read out:

- operating time for the previous 24-hour period

- total operating time since the timer was last set to zero-set.

Coupling counter

The number of relay cutins and cutouts is registered continuously. The number of starts can be read out here:

- Number during the previous 24-hour period

- Total number since the counter was last set to zero-set.

Load shedding

On some installations there is the desire to limit the cut-in compressor capacity so that one can limit the total electrical load in the store for periods.

There is 1 digital inlet available for this purpose.

For digital inlet a limit value is attached for the maximum allowable cut-in compressor capacity.

When a inlet is activated, the maximum allowable compressor capacity is limited to the set limit. This means that if the actual compressor capacity upon activation of the digital inlet is higher than this limit, then so much compressor capacity is cut-out that it will then be on or under the set maximum limit value for this digital inlet.

Overriding of load shedding: To avoid load shedding leading to temperature problems for the chilled products, an overriding function is tted.

A overriding limit is set for the suction pressure as well as a delay time for the digital inlet.

Injection ON

The electronic expansion valves in the refrigeration appliances must be closed when all the compressors are stopped and a restart is blocked. In this way the evaporators will not be lled with liquid which is subsequently passed on to a compressor when regulation is restarted. The function can be attained via data communication.

The function is described based on the sequence of events below: T1) The last compressor is cut-out T2) The suction pressure has increased to a value corresponding

to Po Ref + NZ + “+Zone K” but no compressor can start due to re-start timers or safety cut-out

T3) The time delay “Injection OFF delay” elapses and the injection

valves are forced to close via network signal.

T4) The rst compressor is now ready to start. The forced closure

signal via the network is now cancelled.

T5) The time delay “Comp. Start delay” expires and the rst

compressor being allowed to start.

The reason why the forced closure signal via the network is cancelled before the rst compressor starts, is that it will take some time to distribute the signal to all appliance controllers via the network.

If the suction pressure during load shedding exceeds the set overriding limit and delay times expire then load shedding overrides the signals so that the compressor capacity can be increased until the suction pressure is again under the normal reference value. The load shedding can then be activated again.

Alarm: When load shedding inlet is activated, an alarm will be activated to inform that the normal control has been bypassed. This alarm can however be suppressed if so desired.

Safety functions

Signal from the compressor’s safety controls

The controller can monitor the status of each compressor’s safety circuit. The signal is taken directly from the safety circuit and connected to an input. (The safety circuit must stop the compressor without involving the controller). If the safety circuit is cut out the controller will cut out the relay for the compressor in question and give an alarm. Regulation will continue with the other compressors.

Common safety circuit A common safety signal can also be received from the whole suction group. All compressors will be cut out when the safety signal cuts out.

The alarm is cancelled and renewed cutin of compressor steps is permitted when the following conditions are met:

- the temperature has dropped to 10 K below the limit value

- the time delay prior to restart has been passed. (see later)

Normal condenser control is permitted again when the temperature has dropped to 10 K below the limit value.

Monitoring of min. suction pressure (P0)

The function promptly cuts out all compressor steps if the suction pressure becomes lower than the permitted value. The cutout limit can be dened in the range from -120 to +30°C. The suction is measured with pressure transmitter P0.

At cutout the the alarm function is activated:

The alarm is cancelled and renewed cutin of compressor steps is

permitted when the following conditions are met:

- the pressure (temperature) is above the cutout limit

- the time delay has elapsed (see later).

Monitoring of max. condensing pressure (Pc)

The function cuts in all condenser steps and cuts out compressor steps one by one if the condensing pressure becomes higher than permitted. The cutout limit can be dened in the range from –30 to +100°C. The condensing pressure is measured with pressure transmitter Pc.

Time delays with safety cut-out: In connection with safety monitoring of a compressor it is possible to dene two delay times:

• Cut-out delay time: Delay time from alarm signal from the safety circuit until the compressor outlet cuts out (note that the delay time is common to all security inlets)

• Safety re-start time: The minimum time a compressor must be OK after a safety cut-out until it may start again.

Monitoring of superheat

This function is an alarm function which continuously receives measured data from suction pressure P0 and suction gas Ss. If superheat is registered which is lower or higher than the set limit values, an alarm will be given when the time delay has passed.

Monitoring of max. discharge gas temperature (Sd)

The function gradually cuts out compressor steps if the discharge temperature becomes higher than permitted. The cutout limit can be dened in the range from 0 to +150°C.

The function is started at a value that is 10 K below the set value. At this point the entire condenser capacity is cut in at the same time as 33% of the compressor capacity is cut out (but minimum one step). This is repeated every 30 seconds. The alarm function is activated. If the temperature rises to the set limit value all compressor steps are immediately cut out.

The function takes eect at a value which is 3 K below the set value. At this time the entire condenser capacity is cut in at the same time as 33% of the compressor capacity is cut out (but min. one step). This is repeated every 30 seconds. The alarm function is activated.

If the temperature (pressure) rises to the set limit value, the following will happen:

- all compressor steps will immediately be cut out

- the condenser capacity will remain cut in

The alarm will be cancelled and renewed cutin of compressor steps is permitted when the following conditions are met:

- the temperature (pressure) falls to 3 K below the limit value

- the time delay for restart has been passed.

Delay of Pc max alarms It is possible to delay the “Pc max alarm" message. The controller will still disconnect the compressors, but the sending of the alarm itself is delayed.

Time delay

There is a joint time delay for “Monitoring of max. discharge gas temperature” and “Min. suction pressure” and monitoring of max condensing pressure Pc.

Alarm for too high suction pressure

An alarm limit can be set which will become eective when the suction pressure becomes too high. An alarm will be transmitted when the set time delay has been passed. The regulation continues unchanged.

Condenser

Capacity control of the condenser can be accomplished via step regulation or speed control of the fans.

• Step regulation The controller can control up to 6 condenser steps that are cut in and out sequentially.

• Speed control The analog output voltage is connected to a speed control. All fans will now be controlled from 0 to max. capacity. If an ON/OFF signal is required it can be obtained from fan 1 relay. Regulation can be carried out based on one of the following two principles:

- all fans operate at the same speed

- Only the necessary number of fans is cut in.

Capacity control of condenser

The cut-in condenser capacity is controlled by the condenser pressure’s actual value and depends on whether the pressure is rising or falling. Regulation is performed by a PI controller which may however be changed into a P controller if the design of the plant necessitates this.

On some units, compensation is already made for the "problem" described above, by binary connection of the condenser fans: i.e. a few fans are connected at low capacity and many fans at high capacity, for example 1-2-4-8 etc. In this case, the non-linear amplication is already compensated for, and there is no need for an arc-shaped capacity curve.

It is therefore possible to choose on the controller whether you require an arc-shaped or a linear capacity curve to manage the condenser capacity.

Capacity curve = Linear / Power

Requested capacity Requested capacity

Capacity curve = Power Capacity curve = Linear

Regulating sensor

The capacity distributor regulates from the condenser pressure PC.

Handling sensor errors: An error in the signal will result in a cut-in of 100% condenser capacity, but the compressor regulation will remain normal.

PI regulation

The controller cuts in capacity in such a way that the deviation between the actual condensing pressure and the reference value becomes as small as possible.

P regulation

The controller cuts in capacity that depends on the deviation between the actual condensing pressure and the reference value. The proportional band Xp indicates the deviation at 100% condenser capacity.

Capacity curve

On air-cooled condensers, the rst capacity step will always give comparatively more capacity than the subsequent capacity steps. The increase in capacity produced by each extra step decreases gradually as more and more steps are cut in.

This means that the capacity controller requires more amplication at high capacities than at low capacities. Consequently, the capacity controller for condenser regulation functions with an arc-shaped capacity curve so that amplication is optimal at both high and low capacities.

Reference for condensing pressure

The reference for the regulation can be dened in two ways. Either as a xed reference or as a reference that varies according to the outdoor temperature.

Fixed reference

The reference for the condensing pressure is set in °C.

Floating reference

This function allows the condensing pressure’s reference value to vary according to the outdoor temperature within a dened area. By combining oating condensing pressure with electronic expansion valves a lot of energy saving can be achieved. The electronic expansion valves enables the controller to decrease the condensing pressure according to outdoor temperature and thereby reduce energy consumption by around 2% for each degree the temperature can be decreased.

PI regulation

The reference is based on:

- the outdoor temperature measured with Sc3 sensor

- The minimum temperature dierence between the air temperature and the condensing temperature at 0% compressor capacity.

- the condenser’s dimensioned temperature dierence between the air temperature and the condensing temperature at 100% compressor capacity (Dim tmK)

- how large a part of the compressor capacity has been cut in.

The minimum temperature dierence (min tm) at low load should be set at approximately 6 K as this will eliminate the risk that all fans will be running when no compressors are running. Set the dimensioned dierence (dim tm) at max. load (e.g. 15 K).

The controller will now contribute with a value to the reference which depends on how large a part of the compressor capacity has been cut in.

P-regulation

With P regulation the reference will be three degrees above the measured outdoor temperature. The proportional band Xp indicates the deviation with 100% condenser capacity.

Forced operation of condenser capacity

Forced operation of the capacity can be arranged where the normal regulation is ignored.

The safety functions are cancelled during forced operation.

Forced operation via setting The regulation is set to Manual. The capacity is set in percent of the regulated capacity.

Forced operation of relays If the forced operation is carried out with the switches at the front of an extension module, the safety function will register any exceeding of values and transmit alarms, if required, but the controller cannot cut the relays in or out in this situation.

Limitation of the reference

To safeguard yourself against a too high or too low regulation reference, a limitation of the reference must be set.

PcRef

Max

Min

Capacity distribution

Step regulation

Cut-ins and cutouts are carried out sequentially. The last cut-in unit will be cut out rst.

Speed regulation

When an analog output is used the fans can be speed regulated, e.g. with a frequency converter type VLT.

when the capacity requirement corresponds to the set starting speed. The controller cuts in several fans step by step as the capacity requirement grows and then adapts the speed to the new situation. The controller cuts out fans when the capacity requirement becomes lower than the set minimum speed.

In the conguration of the controller’s outputs it will be the output “FanA1”” that will start and stop the frequency converter.

Joint speed regulation

The analog output voltage is connected to the speed regulation. All fans will now be regulated from 0 to max. capacity. If an ON/ OFF signal is required for the frequency converter, so that the fans can be stopped completely, relay output "Fan 1" is used.

Start Min.

The controller starts the frequency converter when the capacity requirement corresponds to the set starting speed. The controller stops the frequency converter when the capacity requirement becomes lower than the set minimum speed.

Speed regulation + step regulation

Condenser couplings

Coupling of condenser steps

There are no time delays in connection with cutin and cutout of condenser steps beyond the time delay inherent in the PI/Pregulation.

Timer

The operating time of a fan motor is registered continuously. You can read out:

- operating time for the previous 24-hour period

- total operating time since the timer was last set to zero-set.

Coupling counter

The number of couplings is registered continuously. Here the number of starts can be read out:

- number during the previous 24-hour period

- total number since the counter was last set to zero-set.

Motion af ventilatorer

De sidste ventilatorer bliver næppe aktiveret i vinterhalvåret. For at sikre, at ventilatorerne bliver motioneret, vil der for hver 24 timer, blive kontrolleret om alle relæer har været i drift. De relæer, der ikke har været i drift, vil nu blive aktiveret i et halvt minut, men dog med en pause på en time imellem de enkelte relæer. En hastighedstyring køres op til "Start speed".

Start Min.

The controller starts the frequency converter and the rst fan

Safety functions for condenser

Separate monitoring functions

Signal from fan safety controls

The controller can receive signals on the status on a common safety circuit. The signal is obtained directly from the safety circuit and connected to a “DI7” input. If the safety circuit is cut out the controller will give alarm.

Liquid level alarm

An input can be used for monitoring an external signal.

If the signal is interrupted, an alarm will be triggered. A time delay can be set for the alarm.

Room temperature alarm

The function may be used for alarm monitoring of the temperature

Alarm limits can be set for high temperature. Time delays can be set for the alarm,

VSD safety alarm

An input can be used for monitoring frequency converter.

If the signal is interrupted, an alarm will be triggered. A time delay can be set for the alarm.

Miscellaneous

Main switch

The main switch is used to stop and start the controlling function.

The switch-over has 2 positions:

- Normal controlling state (Setting = ON)

- Control stopped. (Setting = OFF)

In addition, there is also a input which is used as an external main switch.

If the switch-over or the external main switch is set at OFF, all the control’s functions are inactive and an alarm is generated to draw attention to this – all other alarms cease.

Refrigerant

Before regulation can be commenced, the refrigerant must be dened. You can select one of the following refrigerants:

1 R12 11 R114 21 R407A 31 R422A

2 R22 12 R142b 22 R407B 32 R413A

3 R134a 13 Brugerdeneret 23 R410A 33 R422D

4 R502 14 R32 24 R170 34 R427A

5 R717 15 R227 25 R290 35 R438A

6 R13 16 R401A 26 R600 36 R513A

7 R13b1 17 R507 27 R600a 37 R407F

8 R23 18 R402A 28 R744

9 R500 19 R404A 29 R1270

10 R503 20 R407C 30 R417A

The refrigerant can only be changed if the “Main switch” is set at “stopped control” and the conguration lock is open.

Warning: Incorrect selection of refrigerant can cause damage to the compressor.

Sensor failure

If lack of signal from one of the connected temperature sensors or

pressure transmitters is registered an alarm will be given.

• When there is a P0 error regulation will continue with 50% cut-in capacity during day operation and 25% cut-in capacity during night operation – but minimum one step.

• When there is a Pc error 100% condenser capacity will be cut in, but the compressor regulation will remain normal.

• When there is an error on the Sd sensor the safety monitoring of

the discharge gas temperature will be discontinued.

• When there is an error on the Ss sensor the monitoring of the

superheat on the suction line will be discontinued.

• When there is an error on the outdoor temperature sensor Sc3 regulation with variable condensing pressure reference cannot be carried out. Instead you use the PC ref. min. value as reference.

Note: An incorrect sensor must be in order for 10 minutes before

the sensor alarm deactivates.

Sensor calibration:

The input signal from all connected sensors can be corrected. A correction will only be necessary if the sensor cable is long and has a small cross-sectional area. All displays and functions will reect the corrected value.

Clock function

The controller contains a clock function. The clock function is used only to change between day/night. The year, month, date, hour and minutes must be set.

Note: If the controller is not equipped with a RTC module (AK-OB 101A) the clock must be reset after each mains voltage outage. If the controller is connected to an installation with an AKAgateway or an AK system manager, this will automatically reset the clock function.

Alarms and messages

In connection with the controller’s functions, there are a number of alarms and messages that become visible in cases of fault or erroneous operation.

Alarm history (service tool only)

The controller contains an alarm history (log) that contains all active alarms as well as the last 40 historical alarms. In the alarm history you can see when the alarm began and when it stopped. In addition, one can see the priority of each alarm as well as when the alarm has been acknowledged and by which user.

Alarm priority:

Dierentiation is made between important and not-so-important information. The importance – or priority – is set for some alarms whilst others can be changed voluntarily (this change can only be done with attachment of AK-ST service tool or AKM software).

The setting decides which sorting / action must be carried out when an alarm is sounded.

• “High” is the most important

• “Log only” is the lowest

• “Interrupted” results in no action

Alarm relay

There is an alarm output on the controller as a local alarm indication.

The relationship between alarm priority and action appears in the schedule below.

Setting Log Alarm relay Send Network AKM destina-

tion High X X X 1 Medium X X 2 Low X X 3 Log only X 4 Interrupted

Alarm acknowledgement If the controller is connected to a network with an AKA gateway or an AK system manager as alarm receiver, these will automatically acknowledge the alarms that are sent to them.

If the controller is used as stand alone without a network connection, the controller can acknowledge the alarms automatically. Then the alarms will automatically go o, when the cause of the alarm dissappears. (Set "Auto act. alarm" to "Enabled" / P40 to 0.)

Alarm LED The alarm LED on the front of the controller indicates the controller’s alarm status.

Blinking: There is an active alarm or an unacknowledged alarm. Fixed light: There is an active alarm that has been acknowledged. Switched o: There are no active alarms and no unacknowledged alarms.

Forced operation via network

The controller contains settings that can be operated from the gateway’s forced operation function via data communication.

When the forced operation function asks about one change, all the connected controllers on this network will be set simultaneously. There are the following options:

- Change to night operation

- Forced closure of injection valves (Injection ON)

- Optimising of suction pressure (Po)

Operating AKM / Service tool / Display

The setup of the controller itself can be carried out via AK-ST 500 service tool software, AKM-software, graphic display AK-MMI or with display EKA 164.

Note: AKM system software does not provide access to all conguration settings of the controller. The settings/read-outs that may be made appear in the AKM menu operation (see also Literature overview).

Authorisation / Passwords

The controller can be operated with System software type AKM with service tool software AK-ST 500 and display.

All methods of operation provide the possibility for access to several levels according to the user’s insight into the various functions.

IO Status and manual

The function is used in connection with installation, servicing and fault-nding on the equipment. With the help of the function, the connected outputs are controlled.

Measurements The status of all inlets and outlets can be read and controlled here.

Forced operation (Service tool only) One can carry out an override of all outlets here to control whether these are correctly attached.

Note: There is no monitoring when the outlets are overridden.

Logging/registration of parameters

As a tool for documentation and fault-nding, the controller provides the possibility of logging of parameter data in the internal memory.

Via AK-ST 500 service tool software one can:

a) Select up to 10 parameter values the controller will continu-

ously register

b) State how often they must be registered

The controller has a limited memory but as a rule of thumb, the 10 parameters can be saved, which are registered every 10 minutes for 2 days.

System software type AKM: The various users are dened here with initials and key word. Access is then opened to exactly the functions that the user may operate. The operation is described in the AKM manual.

Service tool software AK-ST 500: The operation is described in tters on site guide.

When a user is created, the following must be stated: a) State a user name b) State a password c) Select user level d) Select units – either US (e.g. °F and PSI) or Danfoss SI (°C and Bar) e) Select language

Access is given to four user levels.

1) DFLT – Default user – Access without use of password See daily settings and read-outs.

2) Daily – Daily user Set selected functions and carry out acknowledgement of alarms.

3) SERV – Service user All settings in the menu system except for creation of new users

4) SUPV – Supervisor user All settings including the creation of new users.

Display An access code can be dened in one of the menus. You can access all function when the code has been entered.

Via AK-ST 500 one can subsequently read the historical values in the form of graph presentations.

The log only works when the clock has been set.

Display of suction pressure and condensing pressure

Light-emitting diodes on the controller

Internal communication between the modules: Quick ash = error Constantly On = error

One or two separate displays can be connected to the controller. Connection is accomplished by means of wires with plug connections. The display may be placed in a control box front, for example. When a display with control buttons is chosen, a simple operation via a menu system can be performed in addition to the display of suction pressure and condensing pressure. See earlier in the manual.

When a display is connected, it will show the value for what is indicated in "Read out". If you want to see one of the values for what is given under "function" you should use the buttons in the following way:

1. Press on the upper button until a parameter is shown

2. Press on the upper or lower button and nd the parameter you want to read

3. Press on the middle button until the value of the parameter is displayed.

After a short time, the display will return automatically to the "Read out display".

If LED indication of compressor operation, fan operation and various functions is required, display type EKA 166 can be tted.

Status of output 1-8

■ Power

■ Comm

■ DO1 ■ Status

■ DO2 ■ Service Tool

■ DO3 ■ LON

■ DO4

■ DO5 ■ Alarm

■ DO6

■ DO7

■ DO8 ■ Service Pin

Slow ash = OK Quick ash = answer from gateway remains on for 10 mins after network registration Constantly ON = error Constantly OFF = error

External communication

Flash = active alarm/not cancelled Constant ON = Active alarm/cancelled

Network installation

(The LED for "Oil" and "Heat" is not active on this controller.)

Graphic display AK-MMI

With the display is access to most of the controller functions.

Appendix A – Compressor combinations and coupling patterns

In this section, there is a more detailed description of the compressor combinations and the associated coupling patterns. Sequential operation is omitted from the examples since the compressors are only connected in accordance with their compressor number (First In - Last Out principle) and only speed-regulated compressors are used to ll capacity gaps.

Compressor application = single step

The capacity distributor is capable of managing up to 6 one-step compressors according to the following coupling patterns:

• Sequential

• Cyclical

• Best t

Cyclical operation - example Here, all compressors are of the same size and the compressors are cut in and cut-out in accordance with the First-In-First-Out (FIFO) principle, in order to equalise operating hours between the compressors.

- There is operating time equalizing between all compressors

- The compressor with the fewest running hours starts rst

- The compressor with the most running hours stops rst.

Best t - example Here are at least two compressors are of dierent sizes. The capacity distributor will cut in and cut-out the compressors to produce the best possible capacity t (the least possible capacity jump).

Compressor application = 1 x Speed + single step

The controller is capable of controlling one speed-regulated compressor combined with one-step compressors of the same or dierent sizes.

Preconditions for using this compressor application are:

• A speed-regulated compressor that can be of a dierent size than the following one-step compressors

• Up to 5 one-step compressors of the same or dierent capacity (depending on coupling pattern)

This compressor combination can be handled in accordance with the following coupling patterns:

• Sequential

• Cyclical

• Best t

Handling the speed-regulated compressor. For more information on the general handling of the speed-regulated compressor, refer to section "Power pack types".

Cyclical operation - example Here, the one-step compressors are of the same size. The speed-regulated compressor is always the rst to start and the last to stop. One-step compressors should be cut in and cut out in accordance with the First-In-First-out principle in order to equalise operating hours. The speed-regulated compressor is used to ll the capacity gaps between the one-step compressors.

Example:

- There is operating time equalizing between the compressors 1 and 2 (same size in example).

- There is operating time equalizing between the compressors 3 and 4 (same size in example).

Increasing capacity:

- The speed-regulated compressor starts when the desired

capacity equals the start speed

- The following one-step compressor with the smallest number

of operating hours cut in when the speed-regulated compressor is running at full speed (90 Hz)

-When a one-step compressor cuts in, the speed-regulated com-

pressor reduces speed (40 Hz) equivalent to the capacity of the one-step compressor.

Decreasing capacity:

- The following one-step compressors with the most operating hours should be cut out when the speed-regulated compressor reaches minimum speed (30 Hz)

- When a one-step compressor is cut out, the speed- regulated compressor’s speed increases (80 Hz), equivalent to the capacity of the one-step compressor

- The speed-regulated compressor is the last compressor to be cut out when the preconditions for this are fullled.

Best t - example: Here, at least two of the one-step compressors are of dierent sizes. The speed-regulated compressor is always the rst to start and last to stop. The capacity distributor cuts in and cuts out the one-step compressors in order to achieve the best possible capacity t (least possible capacity jump) The speed-regulated compressor is used to ll out the capacity gaps between the one-step compressors.

Example:

Increasing capacity:

- The speed-regulated compressor starts when the desired capacity matches the start speed

- The smallest one-step compressor is cut in when the speedregulated compressor runs at full-speed (90 Hz).

- When the speed-regulated compressor again reaches max. speed (90 Hz), the smallest one-step compressor is cut out (C2) and the big one-step compressor (C3) is cut in.

- When the speed-regulated compressor again reaches max speed (90 Hz), the smallest one-step compressor (C2) is cut in again.

- When the one-step compressor is cut in, the speed is reduced on the speed-regulated compressor (40 Hz) equivalent to the capacity of the cut in capacity

Decreasing capacity:

- The small one-step compressor is cut out when the speed-regulated compressor has reached minimum speed (30 Hz)

- When the speed-regulated compressor again reaches minimum speed (30 Hz), the smallest one-step compressor (C2) is cut out and the big one-step compressor (C3) is cut in.

- When the speed-regulated compressor again reaches min. speed (30 Hz), the large one-step compressor (C3) is cut out and the small one-step compressor (C2) is cut in again.

- When the speed-regulated compressor again reaches min. speed (30 Hz), the small one-step compressor (C2) is cut in.

- The speed-regulated compressor is the last compressor to be cut out when the requirements for this are fullled.

- When the one-step compressor’s capacity is cut out, the speedregulated compressor increases speed (80 Hz) equivalent to the cut out capacity.

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 wil 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 t 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.

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products already on order provided that such alternations can be made without subsequential changes being necessary in specications already agreed. All trademarks in this material are property of the respecitve companies. Danfoss and Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

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Danfoss AK-PC 710 User guide

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