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Danfoss AK-PC 781A User Manual Download Page 115

AK-PC 781A 

Capacity 

controller RS8HE202 © Danfoss 2017-07 

115

2. Offset of the condensing pressure

Reference
Regulation is done using a heat exchanger temperature/receiver 
temperature of e.g. 40°C, the value is adjustable. A temperature 
sensor Shr is installed in the receiver and the temperature is main-
tained in a band around the selected value.

When the temperature goes above the reference plus the half 
band, the gas is routed around the heat exchanger.
The reference can be displaced variably using an external 0-10 V 
signal. 0 V results in no displacement. 10 V results in a displace-
ment indicated by the set value.  

Regulation
The following can be used as a regulation sensor:
- Shr8
- Shr4
- Delta T via the heat exchanger (Shr4-Shr3) of e.g. 4K, but still us-

ing Shr8 as the thermostat sensor.

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. . 

Increasing the condensing pressure
When the temperature is below the reference and heat recovery is 
carried out, the condensation pressure may be increased. 
The pressure is measured using the pressure transmitter Pgc and 
the controller at the valve Vhp.
How much the pressure shall be increased by is determined using 
a setting and an analogue voltage signal. The signal must be a 
0-10 V signal or a 0-5 V signal. 

During heat recovery and a signal of 0 V, the pressure is increased 
to "Pgc HR min." 
At max. signal (e.g. 10 V) the pressure will increase according to 
the setting "Pgc HR offset". 
. 

Up to 5 signals can be received from external regulations. They 
can all increase the pressure, and the controller will use the signal 
that requires the largest offset.  The signal employed is filtered 
over a time period. The length of the period can be set.

Relay output
A relay can be reserved that will pull in if the received signal ex-
ceeds 9.5 V (4.75 V) for more than 10 minutes.
The relay is defined in the function: "Additional heat output".

Remember the isolation amplifier
If signals are received from different controls, e.g. heat recovery 
for one of the inputs, a galvanically insulated module should be 
inserted.

Reference

Band

Summary of Contents for AK-PC 781A

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

Page 2: ...iver pressure 65 Setup control of heat recovery 66 Setup Display 69 Setup Functions for General purpose 70 Separate thermostats 71 Separate pressostats 71 Separate voltage signals 72 Separate alarm inputs 72 Separate PI functions 73 Configuration of inputs and outputs 74 Set alarm priorities 76 Lock configuration 78 Check configuration 79 Check of connections 81 Check of settings 83 Schedule funct...

Page 3: ...ze consumption peaks When the compressor does not start signals can be transmitted to other controllers so that the electronic expansion valves will be closed Regulation of liquid injection into suction line Start stop of liquid injection in heat exchanger cascade MT LT coordination between controllers in cascade control Safety monitoring of high pressure low pressure discharge temperature Capacit...

Page 4: ...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 Controller Top part Extension modules A regulation with few connections can be performed with the controller module alone If there are many connections one ...

Page 5: ...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 a...

Page 6: ...ation 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 Trouble shooting The controller contains a function that continuously follows a number of measurements and deals with them The result indicates whether the function is OK or whether an error may be expected within a given period of ti...

Page 7: ...rt with a specific software and by which input and output signals the relevant application will require If it is an application with few connections the controller module top part with belonging bottom part may be sufficient If it is an application with many connections it will be necessary to use the controller module plus one or more extension modules This section will give you a survey of possi...

Page 8: ... data communication is connected to other controllers in a big ger network 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 Optional connection When a regulation is planned set up it w...

Page 9: ... to 24 V d c AK PS 075 18 VA Supply for controller AK PS 150 36 VA AK PS 250 60 VA 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 for function cut in MMIGRS2 Graphic display with operation Cable between EKA display and controller ...

Page 10: ...U Min 24 V Max 230 V Low and high voltage must not be connected to the same output group Solid state outputs Can be used for loads that are cut in and out frequently e g Oil valves fans and AKV valves Max 240 V a c Min 48 V a c Max 0 5 A Leak 1 mA Max 1 AKV Stepper outputs Used for valves with stepper input 20 500 step s Separate supply to stepper outputs 24 a c d c 13 VA Ambient temperature Durin...

Page 11: ...202 Danfoss 2017 07 11 Dimensions The module dimension is 72 mm 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 ...

Page 12: ...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 flash when the gateway sends an acceptance message Operation The configuration operat...

Page 13: ...ctive at 1 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 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 15 12 V Terminal 16 5 V Terminal 27 12 V Terminal 28 5 V Terminal 17 18 29 30 Cable screen Solid state outputs on 1...

Page 14: ...t signals Supply voltage The supply voltage to the module comes from the previous mod ule in the row Supply voltage to a pressure transmitter can be taken from either the 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 ...

Page 15: ...0A P0B PcA PcB Paux Pgc Prec AKS 32R AKS 2050 MBS 8250 1 xx bar AKS 32 1 zz bar U 0 5 V 0 10 V On Off Ext Main switch Day Night Door Level switch Active at Closed Open Point 5 6 7 8 Type AI5 AI6 AI7 AI8 Point 1 2 3 4 Type AI1 AI2 AI3 AI4 Terminal 9 12 V Terminal 10 5 V Terminal 15 5 V Terminal 16 12 V Terminal 11 12 13 14 Cable screen At the top the signal input is the left of the two terminals At...

Page 16: ... Function The module contains 8 inputs for on off 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 wh...

Page 17: ...9 10 6 DI 6 11 12 7 DI 7 13 14 8 DI 8 15 16 Point Signal Active at DI Ext Main switch Day Night Comp safety 1 Comp safety 2 Level switch Closed voltage on Open voltage off Point 5 6 7 8 Type DI5 DI6 DI7 DI8 Point 1 2 3 4 Type DI1 DI2 DI3 DI4 AK XM 102A Max 24 V AK XM 102B Max 230 V The module can not register a pulse signal from e g a reset function ...

Page 18: ...om the previous module in the row Supply voltage to a pressure transmitter can be taken from either the 5 V output or the 12 V output depending on transmitter type Galvanic isolation The inputs are galvanically separated from the outlets The outlets AO1 and AO2 are galvanically separated from AO3 and AO4 Light emitting diodes Only the two top LED s are used They indicate the following Voltage supp...

Page 19: ...B PcA PcB Paux Pgc Prec AKS 32R AKS 2050 MBS 8250 1 xx bar AKS 32 1 zz bar U 0 5 V 0 10 V On Off Ext Main switch Day Night Door Level switch Active at Closed Open AO 0 10 V Terminal 9 12 V Terminal 10 5 V Terminal 11 12 Cable screen Galvanic isolation AI 1 4 AO 1 2 AO 3 4 Point 5 6 7 8 Type AO1 AO2 AO3 AO4 Point 1 2 3 4 Type AI1 AI2 AI3 AI4 3 Brown 2 Blue 1 Black 3 Brown 2 Black 1 Red At the top t...

Page 20: ...l 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 AK XM 204B only Override of relays ON override OFF no override Fuses Behind the upper part there is a fuse for each output Keep the safety distance Low and high voltage must not be connected to the s...

Page 21: ... 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 8 DO 8 46 47 48 Signal Active at DO Comp 1 Comp 2 Fan 1 Alarm Solenoid valve On Off Point 1 2 3 4 5 6 7 8 Type DO1 DO2 DO3 DO4 DO5 DO6 DO7 DO8 ...

Page 22: ...ition Auto the controller carries out the control 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 AK XM 205B only Override of relays ON override OFF no override Fuses Behind the upper part there is a fuse for each output Keep the safety distance Low...

Page 23: ...C S1 S2 Saux SsA SdA Shr Stw Sgc Pt 1000 P AKS 32R AKS 32 P0A P0B PcA PcB Paux Pgc Prec AKS 32R AKS 2050 MBS 8250 1 xx bar AKS 32 1 zz bar U 0 5 V 0 10 V On Off Ext Main switch Day Night Door Level switch Active at Closed Open DO Comp 1 Comp 2 Fan 1 Alarm Light Rail heat Defrost Solenoid valve Active at on Off Terminal 9 12 V Terminal 10 5 V Terminal 21 12 V Terminal 22 5 V Terminal 11 12 23 24 Ca...

Page 24: ... for controller xx VA per valve A UPS may be necessary if the valves need to open close during a power failure Light emitting diodes There is one row with LED s It indicate the following Voltage supply to the module Communication active with the bottom PC board red error Step1 to step4 OPEN Green Open Step1 to step4 CLOSE Green Close Red flash Error on motor or connection Output 24 V d c 20 500 st...

Page 25: ...40 ETS White Black Red Green CCM CCMT KVS 15 White Black Green Red KVS 42 54 CCMT Valve Module Step Terminal 1 point 9 25 28 2 point 10 29 32 3 point 11 33 36 4 point 12 37 40 Point 1 2 3 4 5 6 7 8 Type AI1 AI2 AI3 AI4 AI5 AI6 AI7 AI8 Terminal 17 12 V Terminal 18 5 V Terminal 19 20 Cable screen Point 9 10 11 12 Step 1 2 3 4 Type AO ...

Page 26: ...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 ...

Page 27: ...ensing pressure in C When the controller starts up the display will show the output that 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 Point No point has to be defined for a display module you simply con nect it EKA 163B EKA 164B EKA 166 Graphic display MMIGRS2 Function Setting and display of values in the c...

Page 28: ...om 100 V a c to 240 V a c Placing On DIN rail Effect Type Output tension Output current Power AK PS 075 24 V d c 0 75 A 18 VA AK PS 150 24 V d c adjustable 1 5 A 36 VA AK PS 250 24 V d c adjustable 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 Supply to a controller Class II ...

Page 29: ... DC should be connected to the communication module The 24 V can be sourced from the same supply that supplies the controller The supply for the communication module is galvani cally separated from the connected extension modules The terminals must not be earthed The power consumption is determined by the power consump tion of the total number of modules The controller strand load must not exceed ...

Page 30: ... the controller is linked up in a network with a system manager Start stop of regulation Regulation can be started and stopped via the software External start stop can also be connected Warning The function stops all regulation including any high pressure regulation Excess pressure can lead to a loss of charge Start stop of compressors External start stop can be connected Alarm function If the ala...

Page 31: ...must be set ON OFF voltage inputs DI This signal must be connected to two terminals The signal must have two levels either 0 V or voltage on the input There are two different extension modules for this signal type low voltage signals e g 24 V high voltage signals e g 230 V When programming the function must be set Active when the input is without voltage Active when voltage is applied to the input...

Page 32: ...er P0 S4 or Pctrl x PI regulation x Max number of compressor steps 10 Max number of unloaders each compressor 3 Identical compressor capacities x Different compressor capacities x Speed regulation of 1 or 2 compressors x Run time equalisation x Min restart time x Min On time x Liquid injection in suction line x Liquid injection in cascade heat exchanger x External start stop of compressors x Oil m...

Page 33: ...outputs in the controller Heat recovery There are adjustment options for hot water and heat containers for heating The controller manages in order of priority 1 tap water 2 heating 3 gas cooler which removes the remaining excess heat Safety circuit If signals are to be received from one or more parts of a safety circuit each signal must be connected to an ON OFF input Day night signal for raising ...

Page 34: ...rature 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 Data from this example is used on the next page The result is that the following modules should be used AK PC 781A controller AK XM 205A input and output module AK XM 208C stepper output...

Page 35: ...k of suction pressure Separate alarm functions via DI 1 Load shedding Start of Heat recovery 1 1 Liquid level Oil level 8 Pulse reset of oil management 1 On off outputs Compressors motors 4 Unloaders Fan motors circulation pumps 3 Alarm relay I m alive relay Inject ON Max 1 Separate thermostat and pressostat functions and voltage measure ments 1 Max 5 5 5 Heat recovery function via thermostat Max ...

Page 36: ...onnection to the connected modules This status can be followed by the light emitting diode When the two catches for the DIN rail mounting are in open posi tion the module can be pushed into place on the 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 8 9 Example continued Length If you use many extension modules the ...

Page 37: ...23 24 Closed Level switch oil comp 4 11 AI 11 25 26 Closed Solenoid valve oil comp 1 12 DO 1 31 32 ON Solenoid valve oil comp 2 13 DO 2 33 34 ON Solenoid valve oil comp 3 14 DO 3 35 36 ON Solenoid valve oil comp 4 15 DO 4 37 38 ON Solenoid valve oil Separator 16 DO 5 39 40 41 ON Circulation pump tw 17 DO6 42 43 44 ON Circulation pump hr 18 DO7 45 46 47 ON Room fan 19 DO8 48 49 50 ON Voltage signal...

Page 38: ...mp gas cooler outlet Sgc 5 1 AI 1 1 2 Pt 1000 Temp by pased gas Shp 2 AI 2 3 4 Pt 1000 Start stop heat recovery tw 3 AI 3 5 6 Closed Gas cooler pressure Pgc 4 AI 4 7 8 AKS 2050 159 Speed control compressor 5 AO 1 9 10 0 10 V Speed control gas cooler fan 6 AO 2 11 12 0 10 V Speed control pump tw 7 AO 3 13 14 0 10 V Speed control pump hr 8 AO 4 15 16 0 10 V Connection diagram Drawings of the individ...

Page 39: ...AK PC 781A Capacity controller RS8HE202 Danfoss 2017 07 39 Example continued ...

Page 40: ...ssary to safeguard the voltage to the controller and valves using UPS Power supply size The power consumption grows with the number of modules used Module Type Number á Effect Controller 1 x 8 8 VA Extension module 200 series _ x 5 __ VA Extension module 100 series _ x 2 __ VA Total ___ VA 12 Example continued Controller module 8 VA 2 extension modules in 200 series 10 VA 2 extension modules in 10...

Page 41: ...ply module 230 V 115 V to 24 V d c AK PS 075 18 VA Supply for controller 080Z0053 AK PS 150 36 VA 080Z0054 x AK PS 250 60 VA 080Z0055 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 084B8578 MMIGRS2 Graphic disp...

Page 42: ...42 Capacity controller RS8HE202 Danfoss 2017 07 AK PC 781A ...

Page 43: ... connected 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 AK XM 102B digital input module AK XM 103B analog input and output module AK OB 110 analog output module ...

Page 44: ...nected 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 off the basic module 2 Mount the extension module in the basic module 3 Put the top part back on the basic module The analog extension module will supply a signal to the ICMTS valve There are two outputs ...

Page 45: ...e The basic module must not be connected to voltage Mounting and wiring continued 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 regard less of where the module is on the row Disassembly is thus done with the two snap catches in the open posi tion In our example four extension modules are to be fitted to the basic mo...

Page 46: ...witch oil comp 4 11 AI 11 25 26 closed Solenoid valve oil Comp 1 12 DO 1 31 32 ON Solenoid valve oil Comp 2 13 DO 2 33 34 ON Solenoid valve oil Comp 3 14 DO 3 35 36 ON Solenoid valve oil Comp 4 15 DO 4 37 38 ON Solenoid valve oil Separator 16 DO 5 39 40 41 ON Circulation pump tw 17 DO6 42 43 44 ON Circulation pump hr 18 DO7 45 46 47 ON Room fan 19 DO8 48 49 50 ON Voltage signal to high pressure va...

Page 47: ...ounting and wiring continued 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 Warning Keep signal cables separate from cables with high voltage ...

Page 48: ... in just under one minute when the light emitting diode Status starts flashing slowly 5 When there is a network Set the address and activate the Service Pin 6 The controller is now ready to be configured Power Comm DO1 Status DO2 Service Tool DO3 LON DO4 I O extension DO5 Alarm DO6 DO7 Display DO8 Service Pin Internal communication between the modules Quick flash error Constantly On error Status o...

Page 49: ...ion This section describes how the controller Is configured Is operated 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 ...

Page 50: ...er an overview of it will always appear In 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 For connecting and operating the AK service tool software please see the manual for ...

Page 51: ...mpressor Common high pressure monitoring Po setting 15 C night displacement 5 K Oil management of each compressor High pressure control Gas cooler with speed controlled fans Pgc Max 100 bar High pressure control with signal from Sgc and Shp Pc regulates floating based on outdoor temperature sensor Sc3 Control of high pressure valve ICMTS Heat recovery for hot tap water Relay and 0 10 V Heat recove...

Page 52: ... for the specific system and a corresponding access code for this person 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 When the controller is supplied it has been set with standard authoriza tion for different u...

Page 53: ... 2 Select Lock Unlock configuration 3 Select Configuration lock Press the blue field with the text Locked 4 Select Unlocked Select Unlocked Configuration continued The controller can only be configured when it is unlocked The values can be changed when it is locked but only for those settings that do not affect the configuration ...

Page 54: ...In the first field you enter a name for what the controller will be controlling The text written in this field can be viewed at the top of all screens together with the controller s address When the time is set the PC s time can be transferred to the controller When the controller is connected to a net work date and time will automatically be set by the system unit in the network This also applies...

Page 55: ...trol enabled To be adjusted later on Show advanced settings This function opens the advanced settings in the various menus Show Tc If selecting yes the Pc pressure will also be shown as temperature External main switch A switch may be connected for starting and stopping the regulation Also opens UPS selection Mon Ext Power loss signal from an UPS Monitoring of external voltage When selecting yes a...

Page 56: ...external switch can be connected which will start and stop the compressor control Control sensor Po Suction pressure Po is used for control S4 Media temperature S4 is used for control 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 infor...

Page 57: ...capacity Minimum capacity at which the compressor will start must be set to a higher value than PWM Min capacity Load shed limits Select which signal is to be used for load limitation only via network a DI network or two DI network Load limitation period Set the maximum time permitted for load limitation Load shed limit 1 Set max capacity limit for load shed input 1 Load shed limit 2 Set max capac...

Page 58: ...ions 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 pres sure 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 cond...

Page 59: ... start Injection Off delay Delay time for Injection off Liq inj suction line Select the function if a liquid injection is required in the suction line in order to keep the discharge gas temperature down Regulation can be done either using a solenoid valve and a TEV or using an AKV valve AKV OD suction line Opening degree of the valve in Inject start SH Superheat value where the liquid injection st...

Page 60: ...n 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 LT sync to MT Select this if the controller is on low pressure control and should be synchronised with high pressure regulation Oil receiver Select whether you wish to activate pressure regulation in one of the oil receiv...

Page 61: ... Yes means pulses will be allowed following compressor stop Oil cycle pre delay Delay time before oil pulses commence Oil cycle post delay Delay time for signal that will stop oil pulses High oil alarm delay If an activation of the level switch is not registered before the time has expired an alarm will be given the compressor not use the oil No of periods No of pulses that are to be enabled in a ...

Page 62: ...tep 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 Speed 1 step First fan speed controlled rest step coupling No of fans Set number of fans Monitoring fan safety Safety monitoring of fans A digital input is used to monitor each fan Fan...

Page 63: ... are not available when the refrigerant selected is CO2 Monitor Air flow Choose whether monitoring is required of the condenser s air flow via an intelligent error detection method Monitoring requires the use of a Sc3 outer temperature sen sor which must be fitted by the condenser s air inlet FDD setting Set error detection function Tuning The controller makes an adjustment to the con denser conce...

Page 64: ...ree of closing Valve max OD Restriction of the ICMTS valve s degree of opening Pgc HR min Read the min acceptable pressure in the high pressure circuit during heat recovery Pgc HR offset Read the pressure increase during heat recovery Ramp down bar min Here you may select how quickly the reference must be changed after a completed heat recovery Temp at 100 bar Temperature at 100 bar Here you may d...

Page 65: ... in the receiver Also becomes regulation reference if the compressors are stopped with the External compressor stop function Prec min limit P band P band under Prec min where the ICMTS valve s degree of opening is increased Prec max limit P band P band over Prec max where the ICMTS valve s degree of opening is decreased Use hot gas dump Select whether hot gas should be supplied if the receiver pre...

Page 66: ...tivated Heat recovery ramp down Configure how quickly the reference for the condenser pressure should be ramped down to normal level after heat recovery Configure in Kelvin per minute Heat recovery cutout Temperature value where the thermostat cuts out the heat recovery Heat recovery cutin Temperature value where the thermostat cuts out the heat recovery Heat recovery circuit applies only when the...

Page 67: ...nal before the new status is used in the regulation 6 Heat reclaim circuits settings are available only when the refrigerant chosen is CO2 and regulation shall be done using a circuit for heating Control mode Here the regulation of the circuit can be started auto and stopped off Setpoint Here the required temperature of sensor Shr8 or Shr4 is set Use ext ref offset A 0 10 V signal must displace th...

Page 68: ...tarted HP CONTROL Pgc HR min Basic reference for the pressure when exter nal voltage signal is received Pgc HR offset Pressure displacement at max voltage signal HP low limit Signal in at which Pgc HR min comes into force HP high limit Signal in at which Pgc HR offset value is used FAN CONTROL Fan Max Cond Ref offset Set the displacement at which the fans shall fully stop Fan low limit Signal in a...

Page 69: ... used The setting is included here for information 3 Display setup Display The following can be read for the four outputs Comp control sensor P0 in temperature P0 i bar absolute Pctrl bar absolute S4 Ss Sd Cond control sensor Tc Pc bar absolute S7 Sgc Shp 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...

Page 70: ...number of required functions In our example we select one thermostat function for temperature control in the compressor room and one alarm function for monitoring the liquid level in the receiver The following number of different functions can be defined 5 thermostats 5 pressostats 5 voltage signal 10 alarm signals 3 PI regulations Configuration continued ...

Page 71: ... each thermostat adjust Whether the thermostat should also be shown in overview display 1 The function is always shown in overview display 2 Name Which of the sensors is used Actual temp Temperature measurement on the sensor that is attached to the thermostat Actual state Actual status on the thermostat outlet Cut out temp Cut out value for the thermostat Cut in temp Cut in value for the thermosta...

Page 72: ... monitor external volt age signals Each volt inlet has a separate outlet to control external automatic controls Set the number of general voltage inputs specify 1 5 Show on overview Name Actual value read out of the measurement Actual state read out of outlet status Min readout State read out values at minimum voltage signal Max readout State read out values at maximum voltage signal Cutout Cut ou...

Page 73: ...erature pressure pressure converted to temperature voltage signal Tc Pc Ss DI etc Setpoint If fixed reference is choosen Reading the total reference Output Here you select the outlet function PWM pulse width modulated fx AKV valve Stepper signal for a step per motor or voltage signal Alarm mode Choose whether an alarm shall be attached to the function If it is set to ON alarm texts and alarm limit...

Page 74: ...tive when the output 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 Load Output Module Point Active at Solenoid valve oil Comp 1 DO1 1 12 ON Solenoid valve oil Comp 2 DO2 1 13 ON Solenoid valve oil Comp 3 DO3 1 14 ON Solenoid valve oil ...

Page 75: ...ery Saux 1 4 Paux 1 3 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 Function Output Module Point Type Voltage signal for high pressure valve ICMTS AO1 1 24 0 10 V Stepper signal for by pass valve CCMT Step 1 3 9 CCMT Speed control compressor AO1 5 5 0 10 V Speed control gas cooler fan AO2 5 6 0 10 V Speed control pump tw AO3 5 7 0 10 V Spee...

Page 76: ...nt 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 Log Alarm relay selection Net work AKM dest Non High Low High High X X X X 1 Medium X ...

Page 77: ...ller RS8HE202 Danfoss 2017 07 77 Press the button to go on to the next page 5 Set alarm priorities for thermostat and extra digital signals Configuration continued In our example we select the settings shown here in the display ...

Page 78: ...ake 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 Configuration continued Press in the field against Configuration lock Select Locked The setup of the controller has now been locked If you subsequently want to make any changes in the controller s setup remember first to unlock the configuration ...

Page 79: ...number and point number that does not exist The selected point number on the selected mod ule had been set up for something different The error is corrected by setting up the output correctly Remember that the setup must be unlocked be fore you can change module and point numbers The settings are shown on a RED background If a setting has turned red you must control the setup again This may be due...

Page 80: ...Outputs Press the button to go on to the next page 6 Check configuration of Analog Inputs Configuration continued The setup of the analog outputs appears as it is supposed to according to the wiring made The setup of the analog inputs appears as it is supposed to according to the wiring made ...

Page 81: ...s OFF MAN ON The output is forced to pos ON 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 By means of the manual control of each output it can be checked whether the output has been correctly connected Cut out the safety circuit for compressor 1 Check that LED DI1 on the extension module module 2 g...

Page 82: ...5 0 V 5 V 2 5 V 0 V Example of the connection between a defined output signal and a manual set value Check that all sensors show sensible values In our case we have no values 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 configuration is not locked Set Control of output voltage to manual...

Page 83: ...the pages the ones that can only be seen via the Scroll bar 4 Safety limits 5 Go back to the overview 6 Select condenser 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 different settings It is all these settings that have to be ...

Page 84: ...it is time to look at the General functions in overview display 2 Press the button to access The first is the thermostat group 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 Check of settings continued The last page contains safety limits and restart times All the defined general functions a...

Page 85: ... schedule function for the night setback of the suction pressure 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 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 ...

Page 86: ...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 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...

Page 87: ... list Press the red cross to remove cancelled alarms from the alarm list 5 Check active alarm again In our case we have a series of alarms We will tidy them up so that we only have those that are relevant 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 plan...

Page 88: ...e bottom of the display 2 Start control First start of control continued Press in the field against Main switch Select ON 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 ...

Page 89: ...apacity in percent Press in the blue field against Manual capacity If you need to manually adjust the capacity of the compressors you can use the following procedure WARNING If you force control the compressors the oil management will be shut down This could cause compressor damages If the wiring of the compressors includes safety relays monitoring will continue See Regulating functions Press the ...

Page 90: ...90 Capacity controller RS8HE202 Danfoss 2017 07 AK PC 781A ...

Page 91: ...AK PC 781A Capacity controller RS8HE202 Danfoss 2017 07 91 5 Regulating functions This section describes how the different functions work ...

Page 92: ...the controller is to control an IT compressor for parallel compres sion the following regulation settings will be required The system type must be set to LT The regulation sensor must be set to Po the signal received from the receiver Prec Handling of sensor error Cap Ctrl Sensor P0 When P0 is used as the regulating sensor an error in the signal will mean that regulation continues with 50 cutin in...

Page 93: ...nction 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 com pensate for the change Override with a 0 10 V signal When a voltage signal is connec...

Page 94: ...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...

Page 95: ...divided by the A value The controller calculates the curve such that regulation is smooth Easy Settings Regulation parameters Kp Tn A A 1 Slowest 1 0 200 3 5 5 0 2 1 3 185 3 5 4 8 3 Slower 1 7 170 3 5 4 7 4 2 1 155 3 5 4 6 5 Default 2 8 140 3 5 4 4 6 3 6 125 3 5 4 2 7 Faster 4 6 110 3 5 4 1 8 5 9 95 3 5 4 0 9 7 7 80 3 5 3 8 10 Fastest 9 9 65 3 5 3 5 User defined 1 0 10 0 10 900 1 0 10 0 1 0 10 0 R...

Page 96: ...hours will be started first At the different stops the compressor with the highest number of operating hours will be stopped first For compressors with several steps the operating time equalizing is carried out between the compressors main steps The left column shows the operating hours according to which the controller equalises The middle column shows as a percentage to what extent the individua...

Page 97: ...s in relation to subsequent compressors 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 In appendix A there is a more detailed description of the coupling patterns for the individual compressor applic...

Page 98: ...t 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 Controlling increasing capacity If the need for capacity becomes larger than Max Speed then the subsequent compres...

Page 99: ...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 capaci...

Page 100: ...d capacity has reached a value that allows the cut in of the next speed regulated compressor at start speed Afterwards both compressors will be cut in together and will run in parallel The following one step compressors will be cut in and out in accordance with the selected coupling pattern Controlling decreasing capacity The speed regulated compressors will always be the last compres sors running...

Page 101: ...led in accordance with the best fit coupling pattern Example Two speed regulated compressors with a nominal capacity of 10 kW and 20 kW respectively Frequency range of 25 60 Hz Two one step compressors of 20 and 40 kW respectively Two independent speed regulated compressors If the two speed regulated compressors need to be controlled asynchronously they must each have their own analogue voltage si...

Page 102: ...ttached delay times for the two digital inlets 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 a load shedding digital inlet is activated an alarm will be activated to inform that the normal control has been bypassed This ala...

Page 103: ...irement signal and the last MT compressor stops MT compressor LT compressor LT inj heat excha MT comp request input Injec heat exchanger output Injec heat exchanger output Injection ON The electronic expansion valves in the refrigeration appliances must be closed when all the compressors are prevented from starting In this way the evaporators will not be filled with liquid which is subsequently pa...

Page 104: ... cuts out Direct using an electrically operated expansion valve of the type AKV Four values are adjusted a start value for the Sd temperature min and max values for overheating and a period time for the AKV valve 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 injectio...

Page 105: ...nnect value for this temperature will always remain at 130 C and the reconnect value at 120 C 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 defined in the range from 120 to 30 C The suction is measured with pressure transmitter P0 At cutout the alarm function is activa...

Page 106: ...pressor that is shut down does not receive any oil When the compressor is in operation a signal from the compres sors oil level switch is expected When the signal is given the following process is carried out Adjustable delay time re started in case of chatter Oil injection commences after delay time sequence The solenoid valve follows the pulse process and the oil is injected Pulse time period ti...

Page 107: ...ls out due to lack of oil it can be reconnected manually in the plant itself This can be done via a pulse signal on a defined analogue input 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 Control principle for emptying the oil separator in the receiver The system...

Page 108: ...Pc is used as the regulation sensor an error in the signal will result in condensator capacity being controlled as a function of the connected compressor capacity The compressor regulation will remain normal Cap Ctrl Sensor S7 If S7 is used as the regulation sensor an error in this sensor will result in further regulation that follows the Pc signal but in ac cordance with a reference that is 5K ov...

Page 109: ...id valve 2 Use of a thermostat for the function This function can be used with advantage where the heat recovery is used to warm up a water tank A temperature sensor is used to activate deactivate the heat recovery function When the temperature sensor becomes lower than the set cut in limit the heat recovery function is activated and the reference for the condenser temperature will be raised to a ...

Page 110: ...he capacity requirement becomes lower than the set minimum speed Start Min Speed regulation step regulation The controller starts the frequency converter and the first fan 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 w...

Page 111: ...lant has been run in and runs under normal operation conditions Capacity limitation during night operation The function is used to reduce the noise from the fans to a minimum It is primarily used in conjunction with a speed control but it will also be active when steps are cut in and out The setting is arranged as a percentage of the max capacity The limitation will be disregarded when safety func...

Page 112: ...d 70 C depending on whether it is winter or summer If the Heat reclaim function is to raise the condensing pressure the temperature may increase to 90 or higher The Sc3 sensor should be positioned so that it measures the air intake temperature for the gas cooler If it measures a temperature that is too high the system s COP will become impaired The Sgc signal must be stable If this cannot be done ...

Page 113: ...f thermo stat The pump has to be variably controlled Stw4 Stw3 Here Delta T over the heat exchanger is used for regulation Here the pump must be controlled using variable speed When the Stw8 temperature has been achieved the gas is routed outside of the heat exchanger With a Delta T controller the reference cannot be displaced using an external signal Stw8 and Stw8a Here regulation is done using t...

Page 114: ...st be installed due to safety reasons Shr2 The controller must know the temperature of the gas that is sent for condensation Shr3 Heat exchanger cold access Used for temperature regulation Shr4 Heat exchanger hot outlet Used for temperature regulation Shr8 Receiver temperature and in relation to the reference Stw2 or Sd The regulation must know the temperature of the gas that is sent into the heat...

Page 115: ... for the pump Increasing the condensing pressure When the temperature is below the reference and heat recovery is carried out the condensation pressure may be increased The pressure is measured using the pressure transmitter Pgc and the controller at the valve Vhp How much the pressure shall be increased by is determined using a setting and an analogue voltage signal The signal must be a 0 10 V si...

Page 116: ...igher the value the greater the need for heat The signal must be a 0 10 V signal or a 0 5 V signal The signal is converted by the controller to 0 100 capacity and will have the following impact a Control of the pump The pump is released to operation The valve is coupled up b Pressure increase The pressure is measured using the pressure transmitter Pgc and the controller at the valve Vhp If necessa...

Page 117: ...ecially developed for the pressure conditions that exist in a transcritical CO2 system The motor section of the valve is an ICAD actuator and is control led by a 0 10 V signal from the controller The valve s degree of opening can be restricted both at the clos ing point and in the entire open point The settings OD Min and OD max are adjusted as of the degree of opening and will restrict the voltag...

Page 118: ...s activated by a signal from the heat recovery 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 Start up at a very low temperature It will be necessary to route the gas outside of the gas cooler if the gas temperature is too low Temperature limits are set under ...

Page 119: ...P belt must be installed to be able to regulate the function but both are standard set to zero which makes the function inactive Receiver pressure s max limit Set a max receiver pressure that will typically be the maximum receiver pressure If the controller records that the receiver pres sure slips into the P band shutdown of the high pressure valve Vhp commences The opening degree will be linear ...

Page 120: ...he desired level The compressor capacity will be vari able and the controller will emit a 0 10 V signal that indicates the desired capacity The function is activated by the MT controller which regularly records the opening degree of the Vrec valve When the opening degree is greater than the set value the MT controller will pull a relay This signal is recorded by the IT controller which starts the ...

Page 121: ...ect IT Select IT compressor From where the coordination with the MT controller is initiated DI input which receives signals when the IT compressor is to begin Relay output which emits signals when the compressor is running The Vrec valve s opening degree when the parallel compression is to start The start signal is first emitted when the opening degree is higher during the entire delay period The ...

Page 122: ...utput will be based on the actual pressure 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 General voltage input with ancillary relay 5 units 5 general voltage inputs are accessible for moni...

Page 123: ...e setting of P part and I part However if the process is quick more careful setup is required A general balancing might be Check max and min settings Increase the integration time so that it is not mixed up with the balancing Reduce Kp to start with Start the process Adjust Kp until the process starts fluctuating and is constantly fluctuating Adjust Kp to half the value Adjust Tn down until the pr...

Page 124: ...ng the Shp signal 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 reflect the corrected value Clock function The controller contains a clock f...

Page 125: ...uently read the historical values in the form of graph presentations The log only works when the clock has been set Forced operation via network The controller contains settings that can be operated from the system units 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 ...

Page 126: ...predefined combina tions which at the same time establish the connections points At the end of the manual an overview of options and connection points is shown After the configuration of this function the controller will shut down and restart x x x o93 Lock of configuration It is only possible to select a predefined configuration or change refrigerant when the configuration lock is open 0 Configur...

Page 127: ...If required this current ensures that the valve main tains its last programmed position This value is limited to a range of 0 70 given in 10 steps Overdrive at Valve Init During valve initialization the amount to overdrive the valve beyond the 0 position to ensure that the valve has fully closed This value is limited to a range of 0 31 Phase Current The current applied to each phase of the stepper...

Page 128: ...s via few compressors Preconditions for using this compressor application are All compressors are the same size The capacity regulated compressor can have up to three unload valves The main step and the unload valves can be different sizes i e 50 25 and 25 This compressor combination can be handled in the following coupling patterns Cyclical General regarding Handling Cutin The capacity regulated ...

Page 129: ...ed to fill capacity gaps Operating hours are equalised between the one step compres sors 3 and 4 Compressor application 4 Only capacity controlled compres sors The controller is capable of controlling capacity regulated piston compressors of the same size with up to 3 unload valves Preconditions for using this compressor application are All compressors are the same size The capacity regulated comp...

Page 130: ...n capacity Decreasing capacity The small one step compressor is cut out when the speed regu lated 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 C...

Page 131: ... of coupling pattern The same frequency band for both speed regulated compressors One step compressors of the same or different sizes depending on the choice of coupling pattern This compressor combination can be handled in accordance with the following coupling patterns Cyclical Best fit Handling the speed regulated compressor For more information on the general handling of the speed regu lated c...

Page 132: ...Example 2 In this example the speed regulated compressors are of different sizes and the following one step compressors are also of different sizes Increasing capacity The smallest speed regulated compressor C1 starts when the desired capacity equals the start speed When the smallest speed regulated compressor C1 has reached max speed 90 Hz the large speed regulated com pressor C2 cuts in and the ...

Page 133: ...AK PC 781A Capacity controller RS8HE202 Danfoss 2017 07 133 ...

Page 134: ...rcuit is defective Saux_ sensor error Signal from extra Temp sensor Saux_ is defective Paux_ sensor error Signal from extra pressure sensor Paux_ is defective All compressors Common safety High Common compr Safety cutout All compressors have been cut out on common safety input Comp 1 safety Comp 2 safety Comp 3 safety _________________ Comp 10 safety Medium Comp X oil pressure cut out Compressor n...

Page 135: ...it is too high Receiver alarm High Prec Alarm from the receiver External power loss High External power loss Supply is interrupted A message alert All other alarms stopped Steppervalve High Stepper Vhp Vrec PI Vliq Open coil Shorted output Error Power failure Check the supply to the current valve In the event of an error or power failure check the supply to the stepper module System alarms The ala...

Page 136: ...uest Loadshed 1 Loadshed 2 Sgc Shp Main Sw Modul 2 AK XM 102B Comp 1 safety Comp 2 safety Comp 3 safety Comp 4 safety VSD C 1 safety Fan 1 safety Modul 3 AK XM 103A Power loss Modul 4 AK XM 208C TW Stw2 TW Stw3 TW Stw4 TW Stw8 HR Shr2 HR Shr3 Modul 5 AK XM 205A TW enable Flow Sw TW HR enable Flow Sw HR Volt input 1 Saux 1 d MT 1 vsd comp 3 single vsd fans Boost Gas cooler Receiver Oil sep Oil rece...

Page 137: ... tw Pump tw HR V3hr HR pump hr GasCool V3gc Thermost 1 Alarm d Sc3 Sd Ss P0 Pc Comp 1 Comp 2 Comp 3 Liq Inject suction Fan 1 Fan 2 Comp 4 MT Comp Release Comp speed Fan speed Fan 2 safety VSD cond safety Speed tw Speed hr HR Shr4 HR Shr8 Vrec CCM Vhp CCMT GasCool Pgc Receiver Prec HR tw V3tw HR tw Pump tw HR V3hr HR pump hr Oil valve Separat 1 GasCool V3gc Thermost 1 Alarm Poil rec Oil Valve C1 Oi...

Page 138: ...tallation or site conditions can give rise to malfunctions of the control system and ultimately lead to a plant breakdown Every possible safeguard is incorporated into our products to prevent this However a wrong installation for example could still present problems Electronic controls are no substitute for normal good engineering practice Danfoss will not be responsible for any goods or plant com...

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