Danfoss AK-PC 781A User Manual
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Danfoss AK-PC 781A User Manual

Capacity controller with recovery function
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User guide
Capacity controller
with recovery function
AK-PC 781A
ADAP-KOOL® Refrigeration control systems
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Summary of Contents for Danfoss AK-PC 781A

  • Page 1 User guide Capacity controller with recovery function AK-PC 781A ADAP-KOOL® Refrigeration control systems Manual...

  • Page 2: Table Of Contents

    Appendix A – Compressor combinations and coupling pat- Setup control of receiver pressure ..........65 terns ......................128 Setup control of heat recovery..........66 Appendix B - Alarm texts ..............134 Setup Display ..................69 Appendix C - Recommended connection ........136 Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 3: Introduction

    1. Introduction SW = 1.4x Application Examples AK-PC 781A is complete regulating units for capacity control of compressors and condensers in refrigeration systems. The con- Traditional capacity control troller is with oil management, heat recovery function and CO 2 gas pressure control.

  • Page 4: Principles

    A regulation with few connections can If there are many connections one or more exten- Examples be performed with the controller module sion modules have to be mounted alone Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 5 S7 gas cooler tempera- ture, hot tap water at heat recovery and heat exchanger tempera- ture at heat recovery. A graphical display with control buttons can also be fitted. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 6 One example may be slow clogging-up of a condenser. When the alarm comes the capacity has been reduced, but the situation is not serious. There will be time to plan a service call. Error Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 7: Design Of A Controller

    This section will give you a survey of possible connections plus assistance in selecting the modules required by your actual ap- plication. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 8: Module Survey

    Extension module with 2x analog output signals If the row of modules needs to be interrupted due to length or external positioning, a communi- cation module should be used. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 9 Accessories Communication modules for controllers where modules cannot be connected continuously Data communication for external extension AK-CM 102 Communication module modules On the following pages there is data specific to each module. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 10: Common Data For Modules

    UL file number: E166834 for XM and CM-modules UL 873, UL file number: E31024 for PC-modules The mentioned data applies to all modules. If data is specific, this is mentioned together with the module in question. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 11 Modules in the 100-series consist of one module Modules in the 200-series consist of two modules Controllers consist of three modules The length of an aggregate unit = n x 72 + 8 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 12: Controller

    A small module (option board) can be placed on the bottom part • Communication with display on RJ11 plug of the controller. The module is described later in the document. • “Service Pin” switch has been activated Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 13 42 - 43 - 44 Defrost Solenoid 18 (DO7) 45 - 46 - 47 valve 19 (DO8) 48 - 49 - 50 Option Board Please see the signal on the page with the module. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 14: Extension Module Ak-Xm 101A

    5 V output or the 12 V output depending on transmitter type. Light-emitting diodes Only the two top LED’s are used. They indicate the following: • Voltage supply to the module • Communication with the controller is active (red = error) Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 15 5 (AI 5) 17 - 18 switch Closed Day/ 6 (AI 6) 19 - 20 Night Open Door 7 (AI 7) 21 - 22 Level switch 8 (AI 8) 23 - 24 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 16: Extension Module Ak-Xm 102A / Ak-Xm 102B

    • Communication with the controller is active (red = error) Off: DI < 2 V a.c. Off: DI < 24 V a.c. • Status of the individual inputs 1 to 8 (when lit = voltage) Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 17 5 - 6 4 (DI 4) 7 - 8 5 (DI 5) 9 - 10 6 (DI 6) 11 - 12 7 (DI 7) 13 - 14 8 (DI 8) 15 - 16 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 18: Extension Module Ak-Xm 103A

    Only the two top LED’s are used. They indicate the following: • Voltage supply to the module • Communication with the controller is active (red = error) Max. load I < 2.5 mA R > 4 kΩ Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 19 17 - 18 Main switch Closed 6 (AO 2) 19 - 20 Day/ Night Open 7 (AO 3) 21 - 22 Door 8 (AO 4) 23 - 24 Level switch 0-10 V AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 20: Extension Module Ak-Xm 204A / Ak-Xm 204B

    Without this safety relay, the controller will fail to stop the compressor if it should run out of oil. See Regulating functions. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 21 34 -36 5 (DO 5) 37 - 39 6 (DO 6) 40 - 41 - 42 7 (DO 7) 43 - 44 - 45 8 (DO 8) 46 - 47 - 48 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 22: Extension Module Ak-Xm 205A / Ak-Xm 205B

    Without this safety relay, the controller will fail to stop the compressor if it should run out of oil. See Regulating functions. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 23 37 - 36 - 39 Light Rail heat 14 (DO6) 40 - 41 - 42 Defrost Solenoid 15 (DO7) 43 - 44 - 45 valve 16 (DO8) 46 - 47 - 48 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 24: Extension Module Ak-Xm 208C

    KVS 15 - KVS 42 Fx: 7.8 + (4 x 5.1) = 28.2 VA  AK-PS 150 CCMT 2 - CCMT 8 CCM 10 - CCM 40 CCMT 16 - CCMT 42 5.1 VA Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 25 Black Green KVS 42-54 Valve Module Step Terminal 1 (point 9) 25 - 28 2 (point 10) 29 - 32 3 (point 11) 33 - 36 4 (point 12) 37 - 40 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 26: Extension Module Ak-Ob 110

    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 Module Point 0 - 10 V Type Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 27: Extension Module Eka 163B / Eka 164B / Eka 166

    Received from the controller via cable and RJ11 connector. Termination The display must be terminated. Mount a connection between the terminals H and R. (AK-PC 781A is terminated internally.) Placing The display can be placed at a distance of up to 3 m from the controller.

  • Page 28: Power Supply Module Ak-Ps 075 / 150 / 250

    2.5 A 60 VA Dimension Type High Width AK-PS 075 90 mm 36 mm AK-PS 150 90 mm 54 mm AK-PS 250 90 mm 72 mm Connections AK-PS 075 AK-PS 150 AK-PS 250 Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 29: Communication Module Ak-Cm 102

    The controller should permanently be set to = ON. Warning Additional modules may only be installed following the installa- tion of the final module. (Here following module no. 11; see the sketch.) After configuration, the address must not be changed. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 30: Preface To Design

    The requirements to the installation are described in a separate Alarm function document. If the alarm is to be sent to a signal transmitter, a relay output will have to be used. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 31: Connections

    ✔ The sum of connections cannot exceed 120 (AK-PC 781A). ✔ The number of extension modules must be limited so that the total power in a row will not exceed 32 VA (including control- ler).

  • Page 32: Design Of A Compressor And Condenser Control

    Heat recovery function for tap water control Oil management Heat recovery function for heating Oil injection in compressor. Shared or individual Controlling the gas cooler (high pressure valve). parallel valve, if applicable Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 33: Connections

    Shr2, 3, 4 and 8 (temperature sensors for heat recovery) • Sd (discharge gas temperature) Must be used when adjusting the heat receiver for heating. Must always be used in connection with compressor regulation. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 34 • Pc regulates based on temperature sensor Sc3 and Sgc Receivers: • Monitoring of CO2 level • Control of pressure in oil receiver • Controlling the tap water receiver temperature, 55°C • Controlling the receiver temperature for the heating circuit, 40°C Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 35: Planning Table

    ___ pcs. á 5 VA = __ AK_OB 110 (2 analog outputs) ___ pcs. á 0 VA = 0 1 pcs. á 8 VA = 8 Sum = Sum = max. 32 VA AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 36: Length

    DIN rail – no matter where in the row the module is found. Removal is likewise carried out with the two catches in the open position. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 37: Determine The Connection Points

    10 (step 2) 29 - 30 - 31 - 32 11 (step 3) 33 - 34 - 35 - 36 12 (step 4) 37 - 38 - 39 - 40 Continued next page AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 38: Connection Diagram

    Drawings of the individual modules may be pressure signal. ordered from Danfoss. Format = dwg and dxf. You may then yourself write the module number in the circle and draw the individual connections. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 39 Example continued: AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 40: Supply Voltage

    Example continued: Controller module 8 VA + 2 extension modules in 200 series 10 VA + 2 extension modules in 100 series 4 VA ------ Power supply size (least) 22 VA Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 41: Ordering

    (controller with RJ11 plug) Length = 3 m 080G0076 Accessories Communication modules for controllers where modules cannot be connected continuously AK-CM 102 Communication module Data communication for external extension modules 080Z0064 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 42 Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 43: Mounting And Wiring

    We have decided to work on the basis of the example we went through previously, i.e. the following modules: • AK-PC 781A controller module • AK-XM 205A input and output module • AK-XM 208C analog input module + stepper output module •...

  • Page 44: Mounting

    Lift the top part off the basic module. 2. Mount the extension module in the basic module There are two outputs. 3. Put the top part back on the basic module Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 45: Mounting Of Extension Module On The Basic Module

    DIN rail – regard- less of where the module is on the row. Disassembly is thus done with the two snap catches in the open posi- tion. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 46: Wiring

    25 - 26 - 27 - 28 CCMT (ETS) CCMT 10 (step 2) 29 - 30 - 31 - 32 11 (step 3) 33 - 34 - 35 - 36 12 (step 4) 37 - 38 - 39 - 40 Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 47 The screen on the pressure transmitter cables must only be connected at the end of the controller. The supply voltage for the pressure transmitter should be taken from the same module that receives the pressure signal. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 48 ■ Service Pin Network installation 5. When there is a network Set the address and activate the Service Pin. Status on output 1-8 6. The controller is now ready to be configured. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 49: Configuration And Operation

    We have decided to work on the basis of the example we went through previously, i.e. compressor control with 4 compressors and high pressure control using heat recovery and gas cooler. The example is shown two pages in. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 50: Configuration

    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. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 51 We have decided to describe the setup by means of an example comprising a MT compressor group and a high pressure control. The example is the same as the one given in the "Design" section, i.e. the controller is an AK-PC 781A + extension modules. Compressor Group • MT circuit •...

  • Page 52: Authorization

    You will access the login display by pressing the icon at the top left corner of the display. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 53: Unlock The Configuration Of The Controllers

    The values can be changed when it is locked, but only for those settings that do not affect the configuration. 2. Select Lock/Unlock configuration 3. Select Configuration lock Press the blue field with the text Locked 4. Select Unlocked Select Unlocked. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 54: System Setup

    This also applies to change-over Daylight saving. Power failure, the clock will be kept running for at least 12 hours. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 55: Set Plant Type

    The controller will then suggest values for all overall pressure values. settings connected with this. Easy Prec ref. provides a group setting for the Fine adjustments can be made if necessary. receiver controller.. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 56: Set Control Of Compressors

    Pctrl: Control pressure from the low-pressure circuit for cascade Po refrigerant type Select refrigerant type P0 Refrigerant factors K1, K2, K3 Only used if “Po refrigerant type” is set to custom (contact Danfoss for information) Pctrl refrigerant type Select refrigerant type...
  • Page 57 Select whether one or two capacity controlled compres- Press the +-button to go on to the sors are allowed to be unloaded at the same time at decreasing capacity next page AO filter Absorber changes at the analog output AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 58 Define here whether this type of protection should be con- nected. For "General", there is a signal from each compressor. Individuel Sd pr. compressor Select whether an Sd measurement should be made for each compressor. Max discharge temp. Cutout temperature. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 59 Select valve signal to the stepper or analog signal Max. liquid injection OD Set max. opening degree of the valve in % Max. discharge temp Max Sd temperature by individual Sd measurements. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 60: Set Oil Management

    (Forced controlled to ON with the setting "Manual" or with the "changeover" on an extension module.) Danfoss recommends this function to avoid any compres- sor damages due to lack of care. (In order to keep things simple, this function is not used as an example.)
  • Page 61 ("high" level contact not activated) No of periods No. of times the valve should open in emptying sequence Period time Time between valve openings. Open time The open time of the valve AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 62: Setup Control Of Condenser Fans

    Absolut max Tc Max value for Tc. If this Tc value is exceeded, the EC voltage will be raised to the value in “EC Voltage abs. max. ” Continues Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 63 OFF: Monitoring is cut out. FDD sensitivity Set the sensitivity of error-detection on the condenser’s air flow. Must only be changed by trained staff. Air flow tuning value Actual tuning values for air flow. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 64: Setup Control Of High Pressure

    Warning If the regulation is stopped dur- ing high-pressure regulation, the pressure will rise. The system must be dimen- sioned to the higher pressure; otherwise, there will be a loss of charge. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 65: Setup Control Of Receiver Pressure

    IT controller. IT comp. Sgc min. The temperature limit for operation with IT compressor. Will not start when a lower value is detected, regardless of the opening degree of the Vrec valve. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 66: Setup Control Of Heat Recovery

    - Max heat reclaim. Here the controller must receive a volt- age signal, but the regulation is increased to also control the pump, fans and gas cooler bypass. Press the +-button to go on to the next page Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 67 The function will reserve a relay. The relay will pull in when the signal for the heat removers reaches 95%. Flowswitch delay: Duration of stable signal before the new status is used in the regulation. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 68 BYPASS CONTROL V3gc bypass stop limit: Signal in % at which the gas cooler connects again after completed disconnect. V3gc bypass start limit: Signal in % at which the gas cooler is disconnected. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 69: Setup Display

    Cond. control sensor Pc bar-absolute Pgc bar-absolute Prec bar-absolute Stw8 Shr8 Speed Compressor Unit readout Choose whether readings are to be in SI units (°C and bar) or (US-units °F and psi) AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 70: Setup Functions For General Purpose

    5 thermostats temperature control in the compressor room and one alarm 5 pressostats function for monitoring the liquid 5 voltage signal 10 alarm signals level in the receiver. 3 PI-regulations Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 71: Separate Thermostats

    Indicate alarm text for low alarm Separate pressostats 3 - Pressostats 1. Select pressostats Settings as the thermostats In our example, separate pressostat functions are not used. 2. Select actual pressostat 3. Define the required pressostat functions AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 72: Separate Voltage Signals

    We have subsequently selected a • Show on overview name for the alarm function and • Name for the alarm text. • Delay time for DI alarm (common value for all) • Alarm text Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 73: Separate Pi Functions

    • Start up time: Time at startup at which the output signal is force-controlled • Startup output: The output signal size at the startup time. • Stop output signal. Size of the output signal when regula- tion is off. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 74: Configuration Of Inputs And Outputs

    DI 1 Alarm input as a fault if the signal is interrupted. DI 2-10 ... PI-1 Di ref External DI PI-1 Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 75 Voltage input 1 - 5 • 0 -5 V, • 0 -10 V, • 1 – 5 V, • 2 – 10 V PI-in temp PI-ref temp PI- in voltage PI-in pres. PI-ref pres. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 76: Set Alarm Priorities

    Se also alarm text page 134. 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 Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 77 Press the +-button to go on to the next page 5. Set alarm priorities for thermostat and extra digital signals In our example we select the settings shown here in the display AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 78: Lock Configuration

    The controller will now make a comparison of selected func- tions and define inputs and outputs. The result can be seen in the next section where the setup is controlled. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 79: Check Configuration

    0 and point number to 0. Remember that the setup must be unlocked be- fore you can change module and point numbers. Press the +-button to go on to the next page AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 80 Press the +-button to go on to the next page 6. Check configuration of Analog Inputs The setup of the analog inputs appears as it is supposed to according to the wiring made. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 81: Check Of Connections

    Check that the value of the alarm for the safety monitoring of compres- sor 1 changes to ON. The remaining digital inputs are checked in the same way. Press the +-button to go on to the next page AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 82 • The sensor has not been connected. • The sensor is short-circuited. 7. Check Analog inputs • The point or module number has not been set up correctly. • The configuration is not locked. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 83: Check Of Settings

    – the ones that can only be seen via The last page contains safety limits and restart times. the ”Scroll bar”. 4. Safety limits 5. Go back to the overview 6. Select condenser group AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 84 1 via the "Show in overview display" setting. Check the settings. 11. Then the pressure switch group Check the settings. 12. Proceed with the remaining functions. 13. The controller setup has been completed. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 85: Schedule Function

    3. Setup schedule 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 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 86: Installation In Network

    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 Con- trols” RC8AC. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 87: First Start 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 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 88: Start The Control

    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”. Any external compressor stop breaker must be ON for the compressors to start. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 89: Manual Capacity Control

    See Regulating functions.) Press the blue field against Control mode Select MAN. 4. Set capacity in percent Press in the blue field against Manual capacity. Set the capacity to the required percentage. Press OK. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 90 Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 91: Regulating Functions

    5. Regulating functions This section describes how the different functions work AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 92: Suction Group

    On cascade systems the signal from Pctrl can be used by both the high-pressure and low-pressure controls either for the controlling sensor or high-pressure monitoring. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 93: Reference

    (10 V) and at min. signal. 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. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 94: Capacity Control Of Compressors

    4 compressor of equal size - The capacity curve will look like this Capacity control AK-PC 781A can control up to 10 compressors. Each compressor can have up to 3 unloaders. One or two of the compressors can be equipped with speed regulation.
  • Page 95 The controller calculates the curve, such that regulation is smooth. 1 = Slowest 3 = Slower 5 = Default 7 = Faster 10= Fastest User defined 1.0 - 10.0 10 - 900 1.0 - 10.0 1.0-10.0 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 96: Capacity Distribution Methods

    - The middle column shows (as a percentage) to what extent the individual compressor has been activated within the last 24 hours. - The right column shows the compressor's current operating time. The value should be reset when the compressor is replaced. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 97: Power Pack Types - Compressor Combinations

    *4) When two speed-regulated compressors are used, they must have the same frequency range. For cyclical coupling patterns, the two speed-regulated compressors should be the same size and the subsequent one-step compressors should also be the same size. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 98 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. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 99 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. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 100 The following one-step compressors will be cut in and out in parallel. The following one-step compressors will be cut in and in accordance with First-In-First-Out principle in order to equalise out in accordance with the selected coupling pattern. operating hours. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 101: Compressor Timers

    When engaging and disengaging, the total hours of operation for the compressors is compared, so they are run an equal number of hours. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 102: Load Shedding

    Alarm: When a load shedding digital 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. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 103: Injection Signal To Heat Exchanger Control

    AK-PC 781A allows the injection to begin when the controller is starting. In this way the evaporators will not be filled with liquid ready to run with the first compressor.

  • Page 104: Liquid Injection In Common Suction Line

    The pulse width modulating signal for the AKV valve shall be taken from one of the controller's four solid state outputs. Time delay A time delay can be set which ensures that the injection is delayed during start up. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 105 An alarm limit can be set which will become effective when the suction pressure becomes too high. An alarm will be transmitted when the set time delay has been passed. The regulation continues unchanged. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 106: Oil Management

    This function divides the pulse count by two. The compressor will then stop, after which the remaining pulses will be made. Both high and low pressure and common oil receiver (+ oil separator) Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 107 There is one reset and this applies to all compressors. Upon reset, all the counters are reset. It can also be reconnected via the service tool indicated in the “Safety monitoring” picture. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 108: Condenser

    Cap. Ctrl sensor = Pc / S7 / Sgc If the regulation sensor is selected for media temperature S7, then Pc is still used as the safety function for high condenser pressure Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 109 When the temperature in the tank has reached the set value, the heat recovery is cut-out again. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 110: Capacity Distribution

    If additional capacity is required, the next fan cuts in at the same time as the first fan switches to minimum speed. From here, the first fan can increase speed again, etc. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 111: Condenser Couplings

    This is accomplished by tuning the function when the condenser is clean. The tuning must not be started until the plant has been run in and runs under normal operation conditions. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 112: Co 2 Transcritical System And Heat Recovery

    The Sgc signal must be stable. If this cannot be done using a sys- tem sensor, it may be necessary to use an immersion tube sensor. If the power supply to AK-PC 781A or the high pressure valve Vhp fails, the system cannot be controlled. We recommend installing an emergency supply (UPS) for both the controller and the valve to avoid faults.

  • Page 113: Circuit For Heat Recovery Or Hot Tap Water

    (With a Delta T controller, the reference cannot be displaced using an external signal.) • Stw8 and Stw8a. Here regulation is done using the two tempera- ture sensors in the receiver. Stw8 is placed at the top and Stw8a further down. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 114: Circuit For Recovery For Heating

    The pump can be controlled on/off or variably. For Shr4 or DeltaT regulation it must be controlled variably. During variable opera- tion the pump will stop when the regulation desires a lower capacity than the selected min. speed capacity for the pump. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 115 The pump can be controlled on/off or variably. For Shr4 or DeltaT regulation it must be variably controlled. During variable opera- tion the pump will stop when the regulation request a lower capacity than the selected min. speed capacity for the pump. . AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 116 The pressure is measured using the pressure transmitter Pgc and the controller at the valve Vhp. If necessary, the pressure will be kept at a value between Pgc HR min. and Pg HR offset. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 117: Circuits For Control Of Co2 Gas Pressure

    Regulation will now follow the set reference curve, but will never go above the set permitted max. pressure for the gas cooler. The current reference can be read from the controller's overview screen. Subcooling Subcooling can be used in the subcritical range. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 118 • From ON at 0%: Here the reference is changed to "Pgc HR Min." • To ON at 100%: Here the reference will increase further using the setting "Pgc HR offset". • Between 0 and 100% the reference is variable. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...

  • Page 119: Receiver Control

    Stop of compressors If the compressors are stopped via the function "External com- pressor stop", the reference for the receiver control will be to the setting "Max. receiver pressure". AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 120: Parallel Compression

    IT compressor is running. The parallel compression (intermediate temperature, ‘IT’) is con- trolled by the third AK-PC 781A. It receives signals from two pres- When the IT capacity’s need drops to min. capacity, the compres- sure transmitters and from the controller on the MT circuit, and it...
  • Page 121 The reference for the receiver pres- sure is set in relative bar. Signal from MT (The “IT comp. state” read-out is the Signal to MT signal received from the IT control- ler.) AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 122: General Monitoring Functions

    Alarm limits can be set for low and high pressure, respectively, including separate alarm delays. The individual pressure control function can be adapted to the relevant application as it is possible to give the pressure control a name and indicate alarm texts. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 123 - Adjust Kp until the process starts fluctuating and is constantly fluctuating - Adjust Kp to half the value - Adjust Tn down until the process starts fluctuating again - Adjust Tn to double values AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 124: Miscellaneous

    • “High’ – Alarm relay is activated only with alarms with high the sensor alarm deactivates. priority • “Low - High’ – Alarm relay is activated only with alarms with “low” priority, “medium” or “high” priority. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 125 State a password whether these are correctly attached. c) Select user level d) Select units – either US (e.g. °F and PSI) or Danfoss SI (°C and Note: There is no monitoring when the outlets are overridden. Bar) e) Select language...
  • Page 126 0: Controller stopped After a short time, the display will return automatically to the 1: Regulating Set point suction pressure "Read out display". Setting of required suction pressure reference in °C Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 127 Stepper Motor Valves Overdrive at Valve Init When selecting a Danfoss stepper motor valve, all settings are fac- During valve initialization, the amount to overdrive the valve, tory set. Here, it is only necessary to select the type of valve.

  • Page 128: Appendix A - Compressor Combinations And Coupling Patterns

    - The capacity controlled compressor is the first to start and the last to stop. - Unloader valves are used to close capacity holes - There is operating time equalizing between the compressors 2 and 3 (same size in example). Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 129 The speed-regulated compressor is always the first 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. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 130 (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. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 131 For more information on the general handling of the speed-regu- lated compressors, refer to section "Power pack types". Cyclical operation - example Here the speed-regulated compressors are the same size The one-step compressors should also be the same size. AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 132 (50 Hz), corresponding to the cut out capacity Example 2: In this example, the speed-regulated compressors are of different sizes and the following one-step compressors are also of different sizes. Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 133 AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 134: Appendix B - Alarm Texts

    Oil level is too low in receiver Recv. High pressure alarm Pressure too high in receiver Rec. high pressure Medium Recv. Low pressure alarm Pressure too low in receiver Rec. low pressure Medium Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 135 The output in question has been put in manual control mode via the AK-ST 500 service tool software Man control ..The output in question has been put in manual control mode via the AK-ST 500 service tool software AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...

  • Page 136: Appendix C - Recommended Connection

    Request recovery 3 single Modul 2 - Comp. 1 Comp. 2 Comp. 3 Comp. 4 VSD C.1 4 fans AK-XM 102B safety safety safety safety safety Cascade Modul 3 - AK-XM 205A Capacity controller RS8HE202 © Danfoss 2017-07 AK-PC 781A...
  • Page 137 Comp. 3 Comp. 4 Fan 1 Fan 2 Fan 3 Fan 4 Comp. speed Volt Saux 1 Volt input MT Comp. Liq. Inject Thermost. Heat input 1 1 (DO) Release Heat Ex. recovery AK-PC 781A Capacity controller RS8HE202 © Danfoss 2017-07...
  • Page 138 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 specifications already agreed.

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