Danfoss AK-PC 551 Technical Brochure Download Page 10

10 

Technical 

brochure RC8CF102 © Danfoss 08-2014 

AK-PC 

551

Example: Application

Application: Digital scroll

The configuration and daily operation of the AK-PC 551 will be 

explained via an application example:

AK-PC 551 controls a refrigeration system with two suction 

groups of compressors and a common air cooled condenser�

Refrigerant: R404A

Suction group MT:

1 digital scroll compressor

2 single step scroll compressors

Control according to suction pressure Po

Set point -15 °C

Monitoring of discharge temperature of digital scroll

Suction group LT:

2 single step scroll compressors

Control according to suction pressure Po

Set point -30°C

Condenser:

Speed control of 4 fans

Common safety monitoring of fans

Relay output for start/stop of VSD

Control according to condensing pressure Pc

Floating reference according to Sc3  outdoor  temp�

Summary of Contents for AK-PC 551

Page 1: ...AK PC 551 Refrigeration Controller Technical brochure ...

Page 2: ...2 Technical brochure RC8CF102 Danfoss 08 2014 AK PC 551 ...

Page 3: ...pplication Digital scroll 10 Example Wiring Diagram 11 Electrical wiring 11 Connection lower level 11 Electrical diagram 11 Connection upper level 11 Example Wizard 12 Wizard setup 12 Example Check IO configuration 14 Wizard assignment of inputs and outputs I 0 14 Assignment of inputs and outputs 14 IO configuration error 15 Example Add extra I O 16 Example Check I O wiring 17 Initialize the contr...

Page 4: ...ving functions and optimization features AK PC 551 can be fully configured through a LCD display The LCD display can be built in and or be a remote connected display AK PC 551 has a compact size of 8 DIN modules All inputs and outputs can be configured for a variety of functions making the controller highly adaptable to any pack application AK PC 551 can be connected into a MODBUS communication ne...

Page 5: ...essure transmitters and temperature sensors 6 digital relay outputs for compressors fans alarm 2 digital solid state outputs for PWM control of Digital scroll or Stream compressor If not used for this purpose they can be used as normal relay outputs 2 analogue outputs for speed control of compressors and condenser fans Speed control of all fans Step control of all fans Condenser combinations The c...

Page 6: ...ase remember the level 3 password Logout Go to the Home screen and hold down the X key for 5 seconds to logout Setup service In the main menu you will find all control parameters divided into sub menus Press ESCAPE to go back to status Press UP to decrease digit Press DOWN to increase digit Press ENTER to login Press LEFT RIGHT to go to next previous digit Configuration and daily operation of AK P...

Page 7: ...cation Running compressor capacity Condenser control sensor Condenser reference Suction control sensor Basic Operation Suction status Home Active alarms Controller information Cleared alarms Press ENTER to see alarm details Press ENTER to see cleared alarm details Running fan capacity temperature Condenser control sensor Condenser status Alarm priority Alarm priority Alarm text Alarm text Active a...

Page 8: ...es that a parameter can be changed A changable parameter has a frame around the setting Control status menu Control settings menu Control status readout Setpoint readout Setpoint selected Press ESCAPE to go one level back Press ESCAPE to go back one level Press ESCAPE to go one level back Press UP to increace the setpoint Press DOWN to see next parameter Press DOWN to see next parameter Press DOWN...

Page 9: ...on Parametric setup Setup wizard Setup wizard is a step by step up and running guideline setting up inputs and outputs automatically Quick configuration Quick configuration is a series of preconfigured applications setting up inputs and outputs automatically Parametric setup Parametric setup is for the expert user who wants to set each parameter individually adjust or finetune settings First time ...

Page 10: ...denser Refrigerant R404A Suction group MT 1 digital scroll compressor 2 single step scroll compressors Control according to suction pressure Po Set point 15 C Monitoring of discharge temperature of digital scroll Suction group LT 2 single step scroll compressors Control according to suction pressure Po Set point 30 C Condenser Speed control of 4 fans Common safety monitoring of fans Relay output f...

Page 11: ...upper level Example Wiring Diagram DO Function DI Function AO Function AI Function DO1 Com 1A DI1 Comp 1A safety AO3 Fan VSD AI1 PoA suction pressure DO2 Comp 2A DI2 Comp 2A safety AO4 AI2 PoB suction pressure DO3 Comp 3A DI3 Comp 3A safety AI3 Pc condensing pressure DO4 Comp 1B DI4 Comp 1B safety AI4 Sc3 outdoor temp DO5 Comp 1A PWM DI5 Comp 2B safety AI5 Sd Comp 1A DO6 Comp 2B DI6 Fan safety AI6...

Page 12: ...h Control setup unit Sat temp Temperature units C Pressure units Bar Wizard screens Settings Plant type Select the overall application of the controller and the refrigerant type Select plant type 2 comp 1 cond Refrigerant type R404A Suction A and B Set the compressor combination as well as the compressor sizes control sensor and set point The pressure range of the pressure transmitter can be set S...

Page 13: ...t via DO Yes Monitor fan safety Common Extra Select whether to use an alarm relay and Modbus network address Alarm output No relay Modbus address 100 Summary Get an overview of the inputs and outputs generated by the wizard Next step Select which main menu to go to Press DOWN to go to the selected menu It is recommended to check the IO input output configuration before starting the controller Appl...

Page 14: ...r capacity control of Digital scroll or Stream 4 compressor are placed on the solid state relays DO5 and DO6 Compressor safety inputs for respectively suction group A and B Speed control of compressor for respectively suction group A and B PoA og PoB suctionpressure are placed on AI1 and AI2 Starting from DO1 Fan safety inputs Speed control of condenser Pc condensing pressure is placed on AI3 Comp...

Page 15: ...ns exceeds the maximum number supported by the hardware an exclamation mark will be shown at the IO type in question This means that you will have to disable some of the IO functions via the configuration menus of the suction groups and condenser in order not to exceed the maximum available inputs or outputs If no exclamation mark is shown it means that at least one IO function has not been assign...

Page 16: ...mation mark at the function This is done in order to show that an IO point is occupied by a function which is not used by the controller In this situation you should either enable the function again in the suction condenser configuration menus or deselect the function in the IO configuration 2 Assign the two Sd discharge temperature sensors to free analog inputs Go to Main menu IO configuration of...

Page 17: ... status menus Go to Main menu IO Configuration Analog Digital inputs Check correct status of all inputs 3 Check correct wiring of the outputs via the IO manual control menus Go to Main menu IO Configuration Analog Digital outputs Check correct electrical wiring by manually overriding the outputs Analog inputs Digital inputs Digital output 1 ON Digital outputs Main switch menu The stars indicates t...

Page 18: ...ts saturated temperature or pressure 2 Set network address Go to Main menu System Network 3 Set the Modbus address in the range 1 199 assuring that the selected address is not occupied by another controller on the network 4 Make sure that the Baud rate of the controller is set to 384 38400 bits per second 5 Make sure that the serial mode is set 8E1 When a network scan is carried out the controller...

Page 19: ...ts Plant type selected Quick configuration As an alternative to the wizard the controller can be set up by selecting one of the preconfigurations defined in the controller Please refer to the application table on page 18 for a full description of all selectable preconfigurations and the associated input and output wiring A quick configuration is done in five steps 1 Select a quick setting 2 Set la...

Page 20: ...2R type pressure transmitters for the suction and condensing pressure with 1 to 12 bar and 1 to 34 bar pressure ranges It is recommended to check the IO input output configuration before starting the controller Default is None App no Display views Suction group A Suction group B Condenser Speed Digital Scroll steam 1 step 1 step Step Speed 17 3CDA 2CB FS 1 2 2 x 16 2CDA 2CB 3F 1 1 2 3 15 3CSA 2CB ...

Page 21: ...2B Fan VSD Alarm Fan Speed PoA PoB Pc Sc3 C1A C2A C3A C1B C2B Main Sw Fan safe 11 2CA 2CB 3F C1A C2A C1B C2B Fan1 Fan2 Fan3 Alarm PoA PoB Pc Sc3 C1A C2A C1B CB2 Main Sw Fan safe 10 4CDA FS C1 C2 C3 C4 C1 PWM Fan VSD Alarm Fan Speed PoA Pc Sc3 SdA Digi C1 C2 C3 C4 Main Sw Fan safe 9 3CDA FS C1 C2 C3 C1 PWM Fan VSD Alarm Fan Speed PoA Pc Sc3 SdA Digi C1 C2 C3 Main Sw Fan safe 8 3CDA 3F C1 C2 C3 Fan1...

Page 22: ...to AO3 or AO4 Example Variable speed drive connected to AO3 How to connect the PWM valve of a digital scroll compressor The Pulse Width Modulated valve PWM of a digital scroll compressor must be connected to one of the solid state relays SSR of AK PC 551 which are the outputs DO5 or DO6 The PWM valve function cannot be selected for any of the other digital outputs The PWM valve of the digital scro...

Page 23: ...put terminals AI1 AI2 AI3 or AI4 The signal type and signal range of the pressure transmitter is setup in the IO configuration menu for analogue inputs In the example the suction pressure signal for suction group A has been selected for analogue input 1 and the signal type is selected as 4 20mA Please be aware that the minimum and maximum pressure ranges are set in relative pressure The power supp...

Page 24: ...t which means that the sensor has to be OK for 10 minutes before the alarm is cleared However normal control procedure will be resumed as soon as the sensor signal is OK The reason for the delay is to avoid numerous alarms if a sensor has a bad electrical connection Alarms can also be cleared manually by entering the alarm detail picture and pressing the X button for 3 seconds If the alarm conditi...

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