Controller for capacity regulation - AKC 24W3 - …files.danfoss.com/TechnicalInfo/Dila/01/rc8aj302.pdf · Controller for capacity regulation - AKC 24W3 ... High pressure cut out

R E F R I G E R A T I O N A N D A I R C O N D I T I O N I N G

Controller for capacity regulation- AKC 24W3

Refrigeration and Air Conditioning Controls

2 Manual RC.8A.J3.02 © Danfoss 04/2002 AKC 24W3

Contents Introduction .............................................................................................................................. 4

Scope .............................................................................................................................. 5

System information .................................................................................................................. 6

Operation .............................................................................................................................. 6

AKA 21 operation ............................................................................................................. 6

PC Operation ................................................................................................................... 6

Capacity regulation of compressor ......................................................................................... 7

Regulation ....................................................................................................................... 7

Measured values ............................................................................................................. 8

Regulation reference and external displacement ......................................................... 10

Neutral zone and regulation band ................................................................................ 10

Neutral Zone ....................................................................................................... 10

+Zone ................................................................................................................. 10

++Zone ............................................................................................................... 10

-Zone .................................................................................................................. 10

- -Zone ................................................................................................................ 10

++Rate (Applied to Reciprocating Compressors) ............................................ 10

+Rate (Applied to Reciprocating Compressors) ............................................... 10-Rate (Applied to all types of Compressors) ..................................................... 10++Rate (Applied to Screw Compressors) ......................................................... 11+Rate (Applied to Screw Compressors) ........................................................... 11

An Overview of the parameters connected with Capacity Regulation ........................ 11

Time delays for cut ins and cut outs (Reciprocating Compressor) ............................... 11

Pulse time and pulse period (Screw Compressor) ....................................................... 12

HiPreSet and LoPreSet bar (Screw Compressor) ........................................................ 12

Lead lag sequence (Screw compressor) ...................................................................... 13

LagOn min .......................................................................................................... 13

Fst.Pulse seconds, Fst.Period seconds and Trans.Dly ...................................... 13

LagStopRng and COP Timer ............................................................................. 14

Motor current limitation (Screw Compressor) ................................................................ 15

DO9 Extra Capacity Output ............................................................................................ 16

Capacity regulation of condenser ......................................................................................... 17

Measured values ........................................................................................................... 17

Discharge temperature set point - Dsc SP °C .................................................... 17

+Zone K .............................................................................................................. 17

-Zone K ............................................................................................................... 17

Slope Td s ........................................................................................................... 17

Speed regulation ..................................................................................................................... 18

Expansion valve operation ..................................................................................................... 19

Setting the superheat Parameters. ................................................................................ 19

Setting the regulation Parameters ................................................................................. 20

Binding between the Compressors and Injection Control ........................................... 20

Monitoring ............................................................................................................................ 21

Compressor safety controls ........................................................................................... 21

No Stop Error - NoStop Amp and NoStop sec ................................................... 21

No Run Error - NoRun sec ................................................................................. 21

Anti-recycle time RTimeA/B min ......................................................................... 21

Time between STOP and START - MinOffA/B min ............................................. 22

Pump Down On Start - PO OS bar and PO OnStart switch ................................ 22

Low Pressure Hold - LPHold bar ....................................................................... 22

Time Delayed Low Pressure - TDLP bar and delay LPDly seconds ................. 22

The permitted number of TDLP trips - TDLPOFF ............................................... 22

Multiplying factor for LPDly time - EntAirMult ..................................................... 22

Low Pressure Cut Out - LP Cut bar .................................................................... 22

AKC 24W3 Manual RC.8A.J3.02 © Danfoss 04/2002 3

Discharge/Suction Differential minimum value - DisSucA/Bbar (Screw ...............

Compressor) ....................................................................................................... 22

Condenser pressure safety controls ............................................................................. 23

High pressure cut out point - HPCOutA/B °C ..................................................... 23

High pressure hold point - HPUnLdA/B K .......................................................... 23

High pressure cut out point - HPHOldA/B K ....................................................... 23

Main Switch ............................................................................................................................ 24

Internal ........................................................................................................................... 24

External .......................................................................................................................... 24

Input Configuration .................................................................................................................. 25

Rfg. Type R ..................................................................................................................... 25

Rfg. Type ......................................................................................................................... 25

Limit Sens ...................................................................................................................... 25

Ext.Ref ............................................................................................................................ 25

Ext.Max K. ...................................................................................................................... 26

Amp.Inp A/B ................................................................................................................... 26

MaxAmp A/B .................................................................................................................. 26

S7 Mode ......................................................................................................................... 26

Filtering of pressure signals - Tau sec ........................................................................... 26

Output Configuration ............................................................................................................... 27

The Compressor configuration ...................................................................................... 27

Reciprocating / Screw selection ......................................................................... 27

Maximum number of steps for each compressor - Max Step A/B ...................... 27

Output Mode - Output ......................................................................................... 27

Time Share ......................................................................................................... 27

Step Mode .......................................................................................................... 28

Pulse Mode ........................................................................................................ 28

Configuration of the DO1 to DO6 outputs for screw compressors ..................... 29

Service Menu ........................................................................................................................... 30

Measurement of Inputs .................................................................................................. 30

Measurement of Inputs .................................................................................................. 30

Force Control of Outputs ................................................................................................ 31

Man.Ctrl .............................................................................................................. 31

AKV A% .............................................................................................................. 31

AKV B% .............................................................................................................. 31

DO 1 .................................................................................................................... 31

DO 2 .................................................................................................................... 31

DO 3.....DO9 ........................................................................................................ 31

AlarmRel.1 .......................................................................................................... 31

AlarmRel.2 .......................................................................................................... 31

Analogue A ......................................................................................................... 32

Analogue B ......................................................................................................... 32

System Measurements/data .................................................................................................. 33

Alarms and messages ........................................................................................................... 34

Access code ............................................................................................................................ 37

AKM Menu description ........................................................................................................... 38

AKA 21 Menu description for Screw Compressors ............................................................ 43

AKA 21 Menu description for Reciprocating Compressors .............................................. 53


Introduction The AKC 24W3 is a complete control unit for capacity regulation of compressors, condensersand controls the evaporator expansion valves in water chiller applications.The controller can be used in combination with other controllers in the Danfoss ADAP-KOOL

refrigeration controls.All status and alarm reporting, set point changing, and configuration is via the AKA 21 SettingModule, with membrane keypad and liquid crystal display screen. Many important parametersare available via the F1, F2 and F3 touch keys, while more advanced configuration is possibleusing the built in circular menu system. Alternatively, configuration and monitoring may becarried out via the built in RS485 DANBUSS link, which can be accessed from a laptopcomputer via a modem or PC gateway using the Danfoss system software type AKM.Pressure, temperature and amperage signals are measured by pressure transmitters, Pt1000temperature sensors and current transducers. These signals are used to calculate the amountof adjustment of applied compressor capacity, to cycle or vary the speed of the condenser fansin the case of air cooled chillers, to pulse width modulate electronic expansion valves, and toprovide unit status, alarm, and setting reports.Reciprocating scroll or screw chillers, having up to two refrigerant circuits, six stages ofreciprocating or scroll compressor capacity, or two step-less controlled screw compressors,can be fitted with the AKC 24W3 controller.The system is suited to the control of either air or water cooled twin circuit chillers fitted withdirect expansion evaporator(s), operating with any of a selection of 23 refrigerants includingR22, R134a, R404A, R407C or R410A, among others. It can be used with other refrigerants forwhich the three Antoine Equation coefficients can be provided by the refrigerant manufacturer.

The application below shows water chiller control of a two circuit shell and tube evaporator,with screw compressors. The second example is with VLT control of the fan motors.

In the diagram above, the water leaving the chiller is measured by S4, and water entering thechiller is measured by S3.

S3

S4


The control of evaporator chilled media temperature and condenser head pressure is handledby neutral zone algorithms, which include a rate of change control facility and time basedswitching logic. When the media to be controlled is within the neutral zone, no changes toapplied compressor or fan stages are made. When the media to be controlled is outside theneutral zone, then the rate of change of controlled media, and the zone in which the controlledmedia actual value falls determine how much change to the applied compressor and/or fanstages is made. The AKC 24W3 controller permits the chilled media temperature to fall fasterwhen the actual temperature is bounded in a “temperature zone” further from the temperaturesetpoint than when it is closer to it, via logic known as “descent rate control”. Similarly, thecontroller causes more fan capacity to be applied when the discharge pressure is further fromthe saturation temperature-equivalent of the condensing pressure, than when it is near it. Thiszonal control allows the controlled media value to approach its setpoint at a desired rate,allowing AKC 24W3 equipped chillers to offer good levels of media control.The facilities also featured in the AKC 24W3 software include high head pressure hold, highhead pressure unloading, low evaporator pressure hold, low suction superheat hold, andcompressor current limiting.

Scope

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System information

Controller type AKC 24W3 is a unit in the ADAP-KOOL refrigeration control system. Thecontroller can be linked up with up with other controllers in the system via a two-core connec-tion - the DANBUSS Data Communication. Through this connection information can betransmitted between the units, like settings, measurements, alarms etc.

Remote serviceThe different messages and alarms can, via telephone network, be transmitted by modems.

Address codingAn address code must be set by means of a number of switches on the controllers front plate.There seven switches for coding. How coding is performed is explained in the installationinstructions for data communication cable (literature No. RC.0X.A).

Connection of control panel type AKA 21DANBUSS connections consist of the following five terminals:

K1 = ScreenK2 = 0VdcK3 = LK4 = HK5 = +5Vdc

The two supply terminals K2 and K5 are only for the connection to an AKA 21 setting module.Terminals K3 and K4 are connected to the data communications bus line. If the bus should beconnected to other units, then the connection is relayed from terminals K3 and K4.

Operation The controller can operate in two different ways. Either by using control panel AKA 21 or bymeans of a PC with system software type AKM.

Setting of the different functions is performed via a menu system. The menu system is built upon several levels where the specific menu is done via the arrow keys.

The complete list of menus is contained in the document “Menu operation via AKA 21”.

Operation takes place from a PC where Microsoft-Windows and System Software type AKM isinstalled. (The PC is connected to the system via Gateway type AKA 243/244)

Setting of the different functions is performed by means of rolling menus and dialogue boxes.Settings can either be made via the keyboard or by using a mouse.

For users of AKM system software the complete list of menus is found in the document “Menuoperation via AKM”.

AKA 21 operation

PC operation


Capacity regulation of compressor

Regulation The AKC 24W3 controller is a neutral zone controller. It will load or unload compressorcapacity until the chilled media temperature is bounded within a neutral zone around thechilled media setpoint. It calculates the chilled media temperature descent/ascent rate, andwill allow a certain rate to occur, which if exceeded, will cause compressor loading/unloadingto be stopped.During chilled media temperature pull-down, two temperature zones are present above theneutral zone, known as the +Zone, and the ++Zone. The chilled media temperature can bepermitted to fall faster in the ++Zone, and when the media temperature falls into the +Zone, aslower descent rate is possible. The two rates are termed the +Rate and the ++Rate respec-tively.The diagram below illustrates the action of Rate control where LvgMedia is in the +Zone or++Zone.

This dual descent rate control method allows the benefits of Proportional + Differential controlto be implemented in an easy to understand and effective manner. The end result is that it ispossible to complete chilled media temperature pull-down quickly, and with the minimum oftemperature undershoot below the target media temperature.When the chilled media does descend below the neutral zone (NZ), it becomes bounded bytwo further zones, the - Zone and the - - Zone. In the - Zone, the applied compressor capacitywill be unloaded until the chilled media is falling at a rate less than the set - Rate. If the chilledmedia does fall into the - - Zone, the applied compressor capacity will be unloaded after a timedelay, irrespective of the Rate at which it is falling/rising. If it continues to fall, the lag compres-sor, or all compressors, will be shut down to prevent the chilled media temperature fromreaching the “Limit” or freeze alarm setpoint, which would cause the unit to be in an alarmcondition. By adjusting the timers that prevent any action as a Zone boundary is crossed, byadjusting the Rates, and by adjusting the individually adjustable +NZ and -NZ components ofthe total neutral zone, it is possible to tune a chillers capacity control behaviour to match thedegree of thermal inertia present in the building cooling load.

T d_s lope T d_s lope

LvgMedia_s lope

LvgMedia_s lope

S 4 - LvgMedia

Rate K/m

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Screw chillers require more finesse from the control scheme than step controlled chillers thathave scroll or reciprocating compressors. To ensure that the slide valve of each compressor ispulsed in the loading or unloading direction by just the right amount to bring about smoothcapacity control, the AKC 24W3 controller offers either fixed pulse width control, where theduration of the loading/unloading pulse is fixed at all times, or variable pulse width control,where the pulse width is determined by the actual values of discharge and suction pressure fora particular System.Two adjustable values are used to set up the necessary pulse width variation, HiPreSet andLoPreSet. The function of these setpoints is described in the appropriate sub-section below.

Measured values The menus belonging to Capacity Control give access to selecting and adjusting the settingswhich give optimum performance for the of the LvgMedia C control. The readings relevant tothe Capacity Control are the following measured menu parameters:

LvgMedia C The temperature of the leaving chilled water/glycol solution (sensor S4)MediaSlope The rate of change of the leaving chilled water temperature (S4) in K/m.EntMedia The temperature of the entering chilled water/glycol solution (sensor

S3).EvapAppA/B K The difference between the leaving chilled water temperature and

evaporator temperature (converted from suction pressure value).Ref °C The leaving chilled water set point, including the effect of the external

reference signal if being used.Limit °C The value of the freeze protection value.S7 °C The temperature of the S7 sensor. This sensor is used only for tem

perature readings and is not connected to the controlling function. Thetext of this sensor can be configured.

A/B Compr. % When the controller is configured for reciprocating compressors(Recip/Screw = 1), these readings display the actual capacity forcompressor A and B.

Safety A/B The external safety digital inputs, that monitor the integrity for circuits Aand B

Run A/B h/10 Displays the hours run by compressors A and B, divided by 10. Thesevalues are settings as well as the updated readings.

A/B Compr. A The current drawn by compressors A and B. The current values areused in the controlling function when the regulator is configured forscrew compressors. The values are used only as readings whenreciprocating compressor are used.

SuctPres A/B b The suction pressure for circuits A and B.

There is also an additional reading that indicate state of the water temperature and thecapacity control. This parameter is called Condition and give a simple but clear indication ofthe controlling status and is based on three character coded message as explained below (zpresents the first digit, y the second and x the third):

Circuit Az7x High Pressure override of Compressor A – The compressor is put on hold, or is

unloading by the cut-out steps or alteration of the slide valve position.z6x Low Suction Pressure conditions in circuit A - No further loading of the Compres

sor A takes place until the pressure increases.z5x Superheat Hold – No further loading of Compressor A.z4x Maximum Motor Current Limitation for Compressor A – See section Motor Current

Limitation.z3x Compressor A inhibited from starting because of restart timer has not elapsed or

safety input is off.z2x Compressor A is on hold because of excessive rate of increase/decrease of

LvgMedia temperature – See section Regulation.z1x Normal operation of Circuit A.z0x Compressors stopped by Main Switch or Capacity ctrl switch.


Circuit Bzy7 High Pressure override of Compressor B – The compressor is put on hold, or is

unloading by the cut-out steps or alteration of the slide valve position.zy6 Low Suction Pressure conditions in circuit B - No further loading of the Compres

sor A takes place until the pressure increases.zy5 Superheat Hold – No further loading of Compressor B.zy4 Maximum Motor Current Limitation for Compressor B – See section Motor Current

Limitation.zy3 Compressor B inhibited from starting because of restart timer has not elapsed or

safety input is off.zy2 Compressor B is on hold because of excessive rate of increase/decrease of

LvgMedia temperature – See section Regulation.zy1 Normal operation of Circuit B.zy0 Compressors stopped by Main Switch or Capacity ctrl switch.

LvgMedia value2yx LvgMedia temperature (S4) is in the ++Zone (high).1yx LvgMedia temperature (S4) is in the +Zone (high).Blank yx LvgMedia temperature (S4) is in the NZ Zone.-1yx LvgMedia temperature (S4) is in the –Zone (low).-2yx LvgMedia temperature (S4) is in the - -Zone (low).

Some examples below illustrate the different values for Condition for various operatingconditions.

Example 1:In this example, the capacity regulation is operating normally within the various zones.

Example 2:In this example, the LvgMedia is initially decreasing more than +Rate within the +Zone.

Example 3:In this example, the LvgMedia is in the ++Zone and there is low pressure conditions in circuit A.

Condition 261

T d_s lope T d_s lope

LvgMedia_s lope

S 4 - LvgMedia

Rate K/m

Loadingstopped

Loadingcontinued

Condition 111Condition 122

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Condition 211

Condition 111

Condition 11

Condition -111

Condition -211


Neutral zone andregulation band

Neutral ZoneThe Neutral Zone for convenience is spilt up into two components +NZ and -NZThe +NZ setting is the temperature range above the LvgMedia setpoint above which the+Zone starts, and in which no control actions are carried out, the latter region forming thepositive temperature dead band.The -NZ setpoint is the temperature range below the LvgMedia set point below which the -Zone starts, and in which no control actions are carried out, the latter region forming thenegative temperature dead band.

+ZoneThe Plus Zone (+Zone) is the temperature range above the positive neutral zone limit (+NZ ).If the LvgMedia is in this range, the normal time delay for the cut-in of reciprocatingcompressor steps is the set value +Time secs.

++ZoneThe ++Zone is defined as the area above the +Zone. If the LvgMedia is in this range, thenormal time delay for the cut-in of reciprocating compressor steps is the set value ++Timesecs.

-ZoneThe Minus Zone (- Zone) is the temperature range below the negative neutral zone limit (-NZ). If the LvgMedia is in this range, the normal time delay for the cut-out of reciprocatingcompressor steps or switching off the screw compressor(s), is the set value -Time secs.

- -ZoneThe - - Zone is defined as the area below the -Zone. If the LvgMedia is in this range, thenormal time delay for the cut-out of reciprocating compressor steps or switching off the screwcompressor(s), is the set value - - Time secs.

++Rate (Applied to Reciprocating Compressors)If the LvgMedia is falling at rate greater than ++Rate (K/m) in ++Zone, then there will be nofurther cut-in compressor steps. The continuation of the cut–in of compressor steps willhappen after rate of descent is less than ++Rate.

+Rate (Applied to Reciprocating Compressors)If the LvgMedia is falling at rate greater than +Rate (K/m) in +Zone, then there will be nofurther cut-in compressor steps. The continuation of the cut–in of compressor steps willhappen after rate of descent is less than +Rate.

-Rate (Applied to all types of Compressors)If the LvgMedia is increasing at rate greater than -Rate (K/m) in –Zone, then there will be nofurther cut-out compressor steps. The continuation of the cut-out of compressor steps willhappen after rate of increase is less than -Rate.

Regulation reference andexternal displacement

The leaving chilled media temperature reference set point is called LvgMedia C. This refer-ence can be displaced by sending an external voltage signal to terminal marked “REF”. Thevoltage must be either 0 - 10 V or 2 - 10 V. The later range has fault detection and will give analarm if voltages falls below 2 V.With the external signal , the reference can be displaced by up to 50 K in positive or negativedirection. The 10 V gives the maximum displacement.See the input configuration section for settings.


Time delays for cut ins andcut outs (ReciprocatingCompressor)

The ++Time, +Time for the time delay of cut in of compressor steps, and -Time, - -Time the timedelay of the cut out of steps apply generally to reciprocating compressors. The delay time -Time and - -Time is also use as the delay time for stopping lag and lead screw compressors.

NOTE:The cut in or cut out of compressor steps can be delayed if the rate of change of the Mediatemperature exceeds the descent/ascent for the respective Zone.

++Rate (Applied to Screw Compressors)If the LvgMedia is falling at rate greater than ++Rate (K/m) in the total positive Zone, then thecompressor capacity will decrease with the normal unloading pulses. The increase incompressor capacity will happen after rate of descent is less than ++Rate and +Rate.

+Rate (Applied to Screw Compressors)If the LvgMedia is falling at rate greater than +Rate (K/m) in the total positive Zone, thenthere will be no further increase in the compressor capacity (compressor on Hold position).The increase in compressor capacity will happen after rate of descent is less than +Rate.

NOTE:1. There is no - -Rate. The cut out of steps or reduction of compressor capacity is

decided irrespective of whether the chilled media temperature is rising or failing inthe - - Zone K.

2. The –Rate applies to the screw compressors in the same way as reciprocatingcompressors in the - Zone.

An Overview of theparameters connectedwith Capacity Regulation

The following table indicates which settings are relevant for the reciprocating and screwcompressors.

retemaraP rosserpmoCgnitacorpiceR rosserpmoCwercS

enoZ++ elbacilppA *elbacilppA

enoZ+ elbacilppA *elbacilppA

enoZ- elbacilppA elbacilppA

enoZ-- elbacilppA elbacilppA

ZN+ elbacilppA elbacilppA

ZN- elbacilppA elbacilppA

emiT++ elbacilppA elbacilppatoN

emiT+ elbacilppA elbacilppatoN

emiT- elbacilppA --elbacilppA

emiT-- elbacilppA elbacilppA

etaR++ )etaR++noitcesees(elbacilppA )etaR++noitcesees(elbacilppA

etaR+ )etaR+noitcesees(elbacilppA )etaR+noitcesees(elbacilppA

etaR- )etaR-noitcesees(elbacilppA )etaR-noitcesees(elbacilppA

* Only applies to the readout of Condition (see section Measured Values)


Pulse time and pulseperiod (Screw Compressoronly)

The set values t1 Pulse and t2 Pulse (secs) for System A and System B are the pulse width ofthe loading and unloading pulses. The smallest possible pulse is one of 0.1 seconds ONduration, the largest possible pulse is 3.0 second in duration. This may be a fixed setting, ormay be varied automatically by the controller to compensate for the effect of ambient tempera-ture conditions on the suction-discharge pressure differential across each compressorunloader block.See Output Configuration for pulse mode setting.

The operation of the outputs for screw compressor is shown below:

The time spacing between load and unload pulses is the set value Period (seconds). This is afixed value, but another Period can be used during unloading pulses that occur when the lagcompressor starts - see Sequence for lead lag.

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HiPreSet and LoPreSet bar(Screw Compressor only)

As mentioned, it is possible to cause the pulse width sent during loading or unloading pulsesto a fixed value. However, if a variable pulse width is chosen, then the pulse width will bevaried in proportion to the differential pressure across the compressor, from discharge tosuction. Two setpoints are provided, HiPreSet and LoPreSet, which are intended to equate tothe discharge and suction pressure respectively during MIDSUMMER operating conditions.Hence, a typical value of HiPreSet might be 20 bar gauge, while that for LoPreSet might be 4bar gauge. (This assumes the refrigerant is R22 or R407C. Values of 12 bar gauge and 2.0 bargauge might be used for R134a systems).

The actual width used for t1 Pulse and t2 Pulse can be calculated by the controller which usesthe equation:

t1 Pulse = 1.0 - (Actual Discharge Pressure - Actual Suction Pressure)/(HiPreSet - LoPreSet)

The same equation applies for the t2 Pulse.

NOTE:The minimum pulse width is 0.1 seconds. The maximum pulse width at any time is 1.0 second.(Higher pulse widths than 1.0 second lead to too rapid an unloading cycle).


Lead lag sequence (Screwcompressor only)

LagOn minThe LagOn timer, calibrated in minutes, prevents a lag compressor from being started until theduration LagOn timer has elapsed. If the chilled media temperature descent rate is less thanthe appropriate Rate for the zone which currently bounds the chilled media temperature, thenthe controller will look to start the lag compressor as soon as the LagOn duration has elapsed.However, if the chilled media temperature descent rate exceeds the appropriate zonal Rateduring the LagOn time duration, then the LagOn timer will be reset to zero, preventing the lagcompressor from starting. This timer is intended to prevent temperature undershoot during pull-down, by preventing a lag compressor from starting when the chilled media temperature isalready falling at a rate necessary to achieve the set leaving media temperature LvgMediawithin the appropriate time-scale.

Fst.Pulse seconds, Fst.Period seconds and Trans.DlyDuring normal capacity control operation of screw compressor(s), the capacity control loadand unload pulses are provided by the t1pulse or t2 pulse, with a Period s between eachpulse. However, during the transition between only the lead compressor running, and thestarting of the lag compressor, a larger Pulse Width and a Shorter Period between pulses isused.The reason for this is that the controller will always attempt to fully unload the lead compressorprior to starting the lag compressor, to minimise total chiller current draw during lag compres-sor starting. The extent to which it is able to do this depends on the length of the Fst.Periodtimer. If this is set too short, then the lead compressor is able to fully unload very quickly, (if Fst.Pulseis large - see below), which risks liquid carryover from the evaporator, and unstable waterconditions. If Fst.Period is set too long, the lead compressor will hardly unload at all before thelag compressor starts.

The intention of using different pulse widths and periods between pulses during lag compres-sor starting is to permit any lead compressor to fully unload quickly, but not too quickly, so thatthe lead and lag compressors can then load at the same rate in a balanced way.The AKC 24W3 controller does not attempt to determine what operating percent capacity acompressor has achieved at any instant, it merely applies a number of simple criteria to decideon whether compressor loading is required.These are:

Is the leaving chilled media temperature in the ++Zone or +Zone zones ?And, is the leaving chilled media temperature falling at the desired rate ?

The controller will pulse load the lead compressor to add capacity until it sees that the chilledmedia temperature is falling at the desired rate, but if it cannot achieve this rate with the leadcompressor alone, it will decide to start the lag compressor.It will then fast unload the lead compressor, so that it knows both the lead and lag compressorsare loaded to about the same percentage load, and then will return to using t1Pulse or t2Pulse for each circuit, and Period s to control pulsed capacity control.

NOTE:It is not detrimental to fully unload the lead compressor for a short while, because while theleaving chilled media temperature may rise for a short while, this will cause the compressorsto be loaded alternately, first Compressor A, then Compressor B, which will ensure balancedloading, and smooth chiller operation.

The length of the transitional period during which the lag compressor is started is determinedby the setting Trans.Dly, the transitional delay timer. If this is set too short, the lead compressorwill not have unloaded sufficiently. If set too long, the lead compressor will continue to run fullyunloaded for an extended period, and proper chilled media temperature control will not beachieved.


NOTE:

1. Ideally, the chiller should be monitored during start up, and each compressor amperagedisplayed using AKM software, or equivalent. The Trans.Dly setting would be adjusted sothat as the lead compressor unloads and the lag compressor starts and loads, the twoamperages reach an equal value via two parabolic curves on the screen, and then risetogether to their respective full load values.

2. That while the Trans.Dly timer is timing, the capacity control parameters t1Pulse, t2 Pulse,and Period s, are replaced by Fst.Pulse and Fst.Period.

LagStopRng and COP TimerThe LagStopRng setting, or Lag Stop Range to describe the setpoint in full, is the chilledmedia range in Kelvin i.e. ( EntMedia - LvgMedia), at which the controller will begin to stop thelag compressor. Normally, a chiller will be required to cool the media to be chilled by about sixKelvin, say from 12 °C to 6 °C. After pull-down, and when the load is around 50% of the totalchiller capacity, the entering chilled media temperature (EntMedia) will fall to approximately 9°C under these conditions, giving a chilled media range across the evaporator of 3K.If the load falls further to 40%, the evaporator range will fall to 2.4K. It is desirable not to run thelag compressor at this point, as the compressor motors of both lead and lag compressors willbecome lightly loaded and therefore in all probability not very efficient.If LagStopRng is set to 2.4K, then when the evaporator range falls to 2.4K, the controller willdecide to stop the lag compressor, after a delay time. By using a value of approximately 40%,the possibility of continual stopping and starting of the lag compressor, and repeated transi-tional fast unloading behaviour, will be avoided.

NOTE:This function is active in the Neutral Zone, -Zone and - -Zone.

The COP Timer is the delay time effective between the instant that the chilled media range fallsto the LagStopRng setpoint, and the instant when the lag compressor is shutdown for capacitycontrol reasons.

NOTE:As soon as the lag compressor has stopped, the lead compressor will be pulse loaded andwill reach around 80% load, as the LagStopRng setting is always set at approximately tenpercent below the chilled media range that would equate to 50% of the chillers full loadcapacity. (This must be adjusted slightly to cope with unequal compressor sizes within onemachine).


Motor current limitation(Screw Compressor)

When a compressor draws sufficient current to exceed ImaxA or ImaxB, the affected compres-sor will be unloaded (using the normal pulse time) by a certain percent of Imax amps definedas deltaA% or deltaB% (depending on the affected compressor), to prevent compressor motoroverload, and spurious nuisance trips. This may be considered to be an “Adaptive” control - itis intended to keep a chiller operating at the highest capacity that is possible, without damageto a compressor due to operation outside operating limits.Imax is therefore normally set to the maximum amperage allowed for the compressor motor, aslisted in the chiller Submittal Data for that machine model, or at a lesser figure if current limitingis to be used to reduce for the cooling capacity of a circuit due to other problems, such as anundersized or faulty circuit breaker etc.

The set values deltaA% or deltaB% are the independent percentages for compressors A andB by which a compressor experiencing amperage exceeding Imax amps, would be unloadedby in order to reduce the amperage drawn to levels within operating limits.

I Delay is the time in seconds from the instant immediately after a current limiting function hasoperated to reduce the compressor current below (Imax - delta%), until a compressor will nextbe permitted to load up if the capacity control algorithm requires a load sequence to takeplace.I Delay is normally set at 30 seconds, but could be set as long as five minutes if desired.

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DO9 Extra Capacity Output The DO9 output is generally used for requesting extra external capacity in the event of chillerfailure or the existing chiller capacity is not sufficient.

The way in which DO9 operates depends on compressor type i.e. screw or reciprocating. Thetable below describes the condition for the DO9 output to be ON.

noitautiS epytrosserpmoC sutatS0OD

)NO(nituc6ODot1ODspetsllA gnitacorpiceR sdnoces06retfaNOsehctiws9OD

NOsrosserpmoCgaLdnadaeL wercS tatsomrehtybdellortnocsi9OD

*NOtonBdnaAsrosserpmoC gnitacorpiceR **sdnoces06retfaNOhctiws9OD

*NOtonBdnaAsrosserpmoC wercS **sdnoces06retfanNOhctiws9OD

Notes:(*) This can be due to an external fault registered by DI1 and/or DI2.(**) This is after anti-recycle has timed out.

When the controller operates with a screw compressor a thermostat can be set to bring in extracapacity if the Media temperature remains high, after the lead and lag screw compressors areoperating. The diagram below illustrates how the thermostat function operates.

Description of Function:The parameter DO9 set C is the set temperature for the LvgMedia water temperature. After thispoint has been exceeded and delay time has elapsed, the DO9 output is switch ON. If thetemperature falls belowDO9 set C before the delay time has elapsed then this timer is reset.The output DO9 will remain ON until the LvgMedia falls below (DO9 set - DO9 diff).The thermostat will only operate when the LvgMedia is in the +Zone or ++Zone, and onlyapplies to screw compressors.

The new parameters which can be set by the AKA 21 setting module or by AKM via a PC are:

Setting Parameters Maximum and Minimum Setting RangeDO9 set C -99.9 to 99.9DO9 diff K 1 to 10

The delay time is fixed (cannot be changed by setting module), but you are welcome to specifythe amount.

DO9 set C

DO9 set C - DO9 diff K

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LvgMedia C

LvgMedia C

DO9 diff K

DO9 OFF DO9 ON DO9 OFF

Time


Capacity regulation of condenser

The discharge pressure of air-cooled chillers, is done by the variable speed control of fansvia a variable speed drives e.g. VLTâ.

The measured pressure DscPres b is the saturated discharge pressure in bar of the dischargegas leaving the compressor, before it enters the condenser.CondTempA/B is the calculated saturated discharge temperature equivalent (in Celsius) of thecondensing pressure measured in bar, for refrigerant gas leaving the compressor, before itenters the condenser.CondSlopeA/B is the rate of change of the rising or falling of the temperature CondTemp. It is auseful parameter in determining the Proportional and Integral settings.

Discharge temperature set point - Dsc SP �CThis setting is the desired value of condensing temperature to be achieved by the condensercontrol algorithm. This should be calculated as the saturation pressure equivalent of thecondenser entry temperature, before any temperature glide effects have been accounted for, ifany are appropriate.A typical value for this setting might be 40°C, even if the chiller was designed to condense at ahigher discharge temperature at full load midsummer conditions. The reason for this is that thefans run for longer, and maintain a more stable LOWER head pressure during periods ofpartial loading, increasing the overall efficiency and stability of the plant all year round.

NOTE:A lower figure may be appropriate, especially for low pressure refrigerants such as R134a, butcare must be taken to ensure that the discharge pressure is not permitted to fall too low inwinter, when there may be insufficient discharge-suction pressure differential to maintainadequate compressor lubricity at start-up, or capacity control due to insufficient hydraulicpressure during loading/unloading.

+Zone KThe +Zone sets the proportional band-width (in Kelvin) for the CondTemp for values greaterthan Dsc SP °C.

-Zone KThe -Zone sets the proportional band-width (in Kelvin) for the CondTemp for values less thanDsc SP °C.

Slope Td sThe rate of change of CondTemp is calculated over period of time defined by Slope Td setting.This parameter is normally set to 5 seconds.

TnIntegration factor given in seconds.

Measured values


Speed regulation

The condenser pressure control operates with fan speed control via the analogue outputsAO 1 for circuit A and AO 2 for circuit B. These outputs can be connected to a frequencyconverter type VLTâ that regulate the speed of the fans.A simple Proportional and Integral controller does the regulation of the condenser fan speedwhere the +Zone and -Zone define the proportional area. The calculated condensertemperature CondTemp is compared with the set point Dsc SP °C and the correspondinganalogue voltage at AO will control the condenser fans so that CondTemp will approach theset point. The Proportional gain factor Kp is equal to:

Kp = 10/(+Zone) + (-Zone)

Example:

If +Zone = 2.5 K and -Zone = 2.5 K

then Kp = 10/2.5+2.5 = 10/5 = 2

i.e. if the CondTemp increases by 2 K, then the analogue outputincreases by 4.0 Volts (2x2 Volts or 40%)

The Integration factor Tn is the standard definition and the range is 20 to 300 seconds.


The control operates the expansion valve so that evaporator has a defined superheat at allload conditions.The function is “adaptive” in a way that a minimum permissible superheat (MSS) is achievedunder varying load conditions. The injection control can be switched either to normal or MOPmode. The latter mode limits the suction pressure to a maximum set value.

The menus belonging to Injection Control give access to selecting and adjusting the settingswhich give optimum performance of the pulse modulated AKV expansion valve. The perform-ance of the Injection Control can be observed from the following measured menu parameters:

SucPres bar ......... The saturated suction pressure transmitter reading at evaporatoroutlet, called Po

EvapTemp C ........ The evaporator temperature converted from saturated suction pressure, called S1

SucTemp C .......... The suction temperature, including superheat i.e. the S2 sensorreading.

SucSHeat K ......... The difference in Kelvin between readings S2 and S1 i.e. superheat(S2 - S1).

AKV OD% .......... The actual AKV Opening Degree in percent, range 0% to 100%.SH ref K ............. The operating superheat reference

There are also additional readings which indicate state of the injection control:

Inj.Ctrl ......... This indicates if Injection control is ON or OFF. Factory setting is alwaysOFF

Inj.State ....... This number indicates the state of the injection control where:0 - OFF State.1 - Normal State.2 - MOP is operating.7 - Error State.

The superheat is limited by the settings for minimum SHmin K and maximum SHmax Ksuperheat. When the measured superheat SucSHeat K is equal or less than SHclose K , theAKV valve will be automatically closed, irrespective of the value of SH ref K.

If the selected valve has an over-capacity in relation to the evaporator, it is possible to limit thevalve’s opening degree. The AKV max % setting is used for this. At setting “100%”, the valve’sopening and closing periods will be adapted to a normal regulating situation. If the setting islower, the opening degree will be correspondingly reduced and result in a limitation of thecapacity

Stable superheat conditions can be obtained by adjusting the values of SHmin K and SHmaxK (SHmax K greater than SHmin K ). Normally these values are increased to achieve stableconditions. It is recommended to adjust one setting at a time and by 1 K each time.

The Superheat/Valve Capacity characteristic is shown below.

Expansion valve operation

Setting the superheatParameters.

OD[ %]

Superheat[K]SHmaxSHminSHclose

AKV max %

10 %


A brief explanation of the parameters is given below.

SHmin K ............. The minimum set superheat reference at closing conditions.SHmax K ............ The maximum set superheat reference for 100% valve capacity.SHclose K .......... The set superheat full closing of the valve.AKV max % ....... The maximum valve opening degree at SHmax K

The superheat is kept in place by Proportional and Integral regulation. The proportional factoris Kp and varies between the set values Kpmin and Kpmax at low load and full load conditionsrespectively. The Integration factor is the set value Tper. These settings have already beenoptimised and it is recommended to keep to factory settings, and should not be changedwithout consultation.Instability of the superheat is usually associated with too small set values of the superheatreferences SHmin and Shmax, and attempts should be made to increase these values.

The set parameter KpP0 is an factor which amplifies the change in evaporator pressure to amomentary change in the AKV valve’s opening degree. Points to remember using this factorare:

• If there are repeated cut out at low pressure, the KpP0 factor can be slightly increased togive higher opening degree at low pressures.

• High values of the KpP0 factor can lead to instability of the suction pressure at start up, andeventual low pressure cut outs.

When the AdapLoad setting is 3 (Factory setting), the injection control will only operate whenthe compressor belonging to same circuit (circuit A or B) is on.If AdapLoad is set to 4, then injection control is completely independent of the status of thecompressors. However, if the digital inputs DI1 or DI2 are off, injection control andcompressor for A or B will be off for both AdapLoad values.(This function is the same as found in the AKC24W and AKC24W2 controllers).

Setting the regulationParameters

Binding between theCompressors andInjection Control.


Monitoring

Compressor safetycontrols

This menu contains the setpoints that control the starting of a lag screw compressor, and theoperating point of most safety controls that will stop a compressor in the event of an alarmcondition.

No Stop Error - NoStop Amp and NoStop secIf the controller decides to shut down a compressor, but it detects that the amperage beingdrawn by that compressor does not fall to a value lower than the NoStop Amp setting withinthe duration of the set timer NoStop sec, then a “NoStop” alarm will be registered, and thealarm output relay for the affected System will become open circuit, signalling an alarm ispresent.When an alarm is registered, the plant manager should, upon investigation see that the alarmis “NoStop”, and immediately proceed to the location of the chiller, and switch the mainsisolator from the ON position to the OFF position.A “NoStop” alarm will be caused by a contactor contact welding in the ON position, assumingthat the compressor circuit breaker does not detect this and trip before a “NoStop” alarm canoccur.

NOTE:Burnt contactor contacts may occur during normal operation to a small degree. If a motorwinding fault or starter control circuit loose connection occurs, then a contactor may draw morecurrent through one phase, leading to abnormal contactor contact burning, or chattering of acontactor that could lead to spurious circuit breaker tripping. If circuit breaker contact burningon one phase is evident, ALWAYS be careful to look in detail for control circuit causes ofburnout. If all phases are burnt, suspect excessive panel temperatures, or excessive chillercooling load are present.

No Run Error - NoRun secWhen the controller decides to start a compressor, under the dictates of the capacity controlalgorithm, it will poll the digital inputs DI 1 or DI 2 after the set timer NoRun sec has elapsed.If either of these digital inputs is in an OFF condition after the NoRun timer has timed out, theassociated compressor start at the digital output (DO 1 or DO 2) will be switched OFF, and a“NoStart” alarm will be generated. The status of DI 1 or D1 2 is ignored by the controller duringthe duration from the starting of a compressor until the NoRun timer has timed out.

The purpose of the NoRun Error function is to indicate to the end user that an external safetycircuit device is in a TRIP or OFF condition, and the controller needs to start the associatedcompressor. These devices include circuit breakers, power on switches, motor protectors,motor overloads, high oil or discharge temperature thermostats, and any custom safetydevices.

NOTE:Normally, the digital inputs DI 1 and DI 2 of the AKC24W3 controller are not used in the sameway as the AKC24W(2) controllers. In the later controllers, the contact to digital inputs has tobe closed (ON) before the controller outputs DO are switched ON.If the NoRun timer is set to 0 sec, then DI1 and DI2 will have same function as AKC24W(2)controllers.

Anti-recycle time RTimeA/B minThe set value RTime is the anti-recycle time for the compressors, and applies from START toSTART, in minutes. A setting of one minute is appropriate for Copeland scroll compressors,ten minutes for small reciprocating compressors, and fifteen minutes for large reciprocatingcompressors and screw compressors.


Time between STOP and START - MinOffA/B minThis is the timer which prevents a compressor from starting at once, after the RTime hasexpired. The setting is minutes and is the time interval between STOP and STOP of thecompressor. Usually a one minute setting is appropriate.

Pump Down On Start - PO OS bar and PO OnStart switchThis setting will hold an AKV expansion valve shut at start-up until the PO OS bar pressure hasbeen reached. It is intended to allow a pump-out to occur at start up to prevent any liquidrefrigerant entering the compressor at the first start, if there is any lying in the evaporator.This function can be switch On or OFF by the PO OnStart switch which has a default value OFF.There is no pump-out on start in this position.

Low Pressure Hold - LPHold barIf the suction pressure drops to the LPHold bar set value, no further compressor loading will bepermitted. This is intended to prevent a Time Delayed Low Pressure TDLP trip from occurring.

Time Delayed Low Pressure - TDLP bar and delay LPDly secondsIf the suction pressure drops to the TDLP bar set value, and remains there or below for morethan the LPDly seconds setting, the compressor will shutdown, and a time delayed lowpressure trip will be registered in the alarm history.

The permitted number of TDLP trips - TDLPOFFThis setting determines how many TDLP trips will be reset automatically before a manual resetis required. If this setting is set to 3, the controller will allow three TDLP trips to reset automati-cally before a chiller will be locked off on that circuit and require a manual reset.

Multiplying factor for LPDly time - EntAirMultIf the S7 sensor has been configured so that it measures “Entering Air Temperature”, then ifthis setting is set to EntAirMult = 4, the LPDly timer will be set to four times its own setting.i.e. if the LPDly timer is set to 1 minute, and the EntAirMult setting is set to 4, the actually timedelay appropriate to a time delayed low pressure trip will extend to 4 minutes.

Low Pressure Cut Out - LP Cut barThe LP Cut bar setting is the Low Pressure Cut Out threshold setting in bar gauge, causing theassociated compressor to stop without delay, which in turn generates a manual reset lowpressure alarm. The compressor for this circuit cannot start before the pressure has increased,the alarm reset and the anti-recycle time has expired.

NOTE:ALL low pressure settings including LPHold bar, TDLP bar, and LP Cut bar can be set to aminimum value –1 bar. This means that the Time Delayed Low Pressure TDLP bar can beused on compressor start up if the LP Cut bar is set to –1 bar.

Discharge/Suction Differential minimum value - DisSucA/Bbar (Screw Compressor)The setting DisSucbar is the minimum level of the discharge/suction pressure differential inbar that can be permitted for screw compressors to be properly lubricated and the rotorssealed. A setting of 2.0 bar is normally appropriate.


Condenser pressuresafety controls

High pressure cut out point - HPCOutA/B �CThis is the saturation temperature equivalent, of the discharge pressure in bar, which ifreached will cause the associated compressor to shutdown immediately, and a High Pressurealarm is given.This is a manual reset alarm, and prevents loss of gas due to high System pressure, orcompressor motor damage due to too high a discharge/suction pressure differential. Thissetting should be chosen to equate to the saturation temperature equivalent of the dischargepressure measured at the compressor outlet.It should NOT include for any temperature glide effects.

High pressure hold point - HPUnLdA/B KThis is the amount of saturation temperature differential, in Kelvin, below the HPCOutA/Bsetting, at which unloading of compressor stages/capacity will be caused to occur, if a Systemdischarge pressure exceeds the pressure equivalent of the HPCOutA/B setting, less theHPUnldA/B differential.For example, if the HPCOutA/B setting is 58°C, and the HPUnldA/B setpoint is 5K, thencompressor capacity will be unloaded until the discharge pressure has fallen to an extentwhere its saturation temperature equivalent has fallen to 53°C.For screw compressors, the slide valve is pulsed in the unloading direction until the dischargetemperature equivalent of the discharge pressure has fallen below the value of the settingHPHOldA/B.For reciprocating compressors, the associated compressor is unloaded one step every 30seconds until CondTemp has fallen below the HPHOldA/B setting.For scroll tandem compressors, one of the two compressors is switched off in the associatedSystem. For single scroll compressors, the associated compressor is switched off.

High pressure cut out point - HPHOldA/B KThis is the amount of saturation temperature differential, in Kelvin, below the HPCOutA/Bsetting, at which no further loading of the applied compressor stages/capacity will be causedto occur, if a System discharge pressure exceeds the pressure equivalent of the HPCOutA/Bsetting less the HPHOldA/B differential.


Main Switch

The controller has two functions that can start/stop the regulation. A function switch inside theunit can be set via the control function and external input can connected to a switch.

The internal switch called MainSwitch has three positions:

Normal regulation: Setting = 1Regulation stopped: Setting = 0Service Function: Setting = -1

If the switch is set to position 0 or -1, all the controlling functions are inactive. An alarm with thetext “Standby mode” is generated to indicate that regulation has stopped. If the switch is inposition 1, regulation has started for functions with “ON”.

External switches must be made before the AKC 24W3 controller can start a compressor.These are connected to two digital inputs located at DI 4 and DI 5. The chilled media flowswitch, (and chilled media pump I/O pressure differential switch if one has been fitted), shouldbe connected across DI 4 at terminals Z1, Z2. The controller will not start a compressor if theflow switch input is not made and an alarm is generated.

The Unit Enable signal, which is an external MainSwitch is connected to the Z3, Z4 terminalsat the digital input DI 5. If this switch is not used, the input must be short circuited for normalcontroller operation.

The combination of the two external digital inputs DI 4 (flow switch), DI 5 (Enable switch) andthe internal MainSwitch is given in the following table.

hctiwslanretxE hctiwSniaM edomrellortnoC

esolc/nepO 1- edomecivreS

nepoenoynA 0 FFO

nepoenoynA 1 FFO

desolcenO 0 FFO

desolcenO 1 FFO

desolchtoB 1 NO

In addition to the above table, the sequence of operation of the digital inputs DI 4 and DI 5 isas follows:

4IDhctiwswolF 5IDhctiwselbanE esnopseR noitcarellortnoC

NO NO delbanetinUgnitareporellortnoC

lortnoclamroN

FFO FFO delbanetinUdeppotsrellortnoC

lortnoclamroN

NO FFO delbanetinUdeppotsrellortnoC

lortnoclamroN

FFO NO ffodekcoltinUdeppotsrellortnoC

teser.naM-tluafwolF

NOTE:During configuration in the “Input Configuration” and “Output Configuration”, the DI 4 and DI 5inputs must be open before settings in these menus can be changed.

Internal

External


Input Configuration

This menu permits the user to configure the AKC 24W3 controller inputs to suit the refrigeranttype and chilled media type to be used, the amount of external chilled media temperaturereset to be used (if any), the size of chiller in which the controller is fitted, and to define thefunction of the S7 temperature sensor. All these settings are found in the Comp.Cap. Settingsmenu.

This parameter shows the currently selected refrigerant type by R number. Pressing downarrow takes the user to the refrigerant choice setting Rfg. Type.

Before the controller can operate normally, the refrigerant must be defined. The followingrefrigerants can be selected by setting Ref. Type R number range 0 to 23.

1 R12 9 R500 17 R5072 R22 10 R503 18 R402A3 R134a 11 R114 19 R404A4 R502 12 R142b 20 R407C5 R717 13 User-defined 21 R407A6 R13 14 R32 22 R407B7 R13b1 15 R227 23 R410A8 R23 16 R401A

NOTE:By using the AKM software, it is possible to manually enter the actual values of the threeAntoine coefficients, for refrigerants that are not in the standard list of refrigerant types.

The Limit Sens setting defines which sensor is used as the Limit, i.e. the FROST PROTECTIONTHERMOSTAT. It is vitally important for water chillers that the leaving water sensor is chosento act as the Limit Sensor. To do this, the Limit Sens setpoint should be set to Limit Sens = 2.Other sensors can be used if a condensing unit is being made. The list is given below:

0: No sensor1: S32: S43: PoA4: PoB5: The smallest value of PoA/PoB

The Ext.Ref can displace the chilled media temperature setpoint by a set amount.This function can used to displace the chilled media set point downwards so that chiller toseek a new lower set point value in the case of ice storage systems.This function can used also to displace the set point in the positive direction in the case ofheat recovery applications or to displace the reduced wet bulb temperatures in air handlingunit systems in winter.The Ext.Ref can be set either 1 or 2. If set to 1, a 0-10 V displacement signal may be applied,where 0 V is zero displacement, and 10 V is maximum displacement.If Ext.Ref is set to 2 then, the zero displacement position coincides with 2 V and the range is 2-10 V.

NOTE:If 2 is selected for Ext.Ref an alarm will be generated if the voltage at input is less than 2 V.

Rfg. Type R

Rfg. Type

Limit Sens

Ext.Ref


The Ext.Max K setting determines the total amount of chilled media temperature set point isdisplaced upon the application of an external reference signal, in Kelvin.

This setting determines what type of input signal will be properly received by the AKC 24W3controller from an amperage transducer. It is advisable that this setting is set to 1, which willallow a voltage input. 2V = zero amps, 10V = maximum amps. A setting of 2 will require a 4-20milliamp input signal. The appropriate current transducer should be chosen to feed theamperage inputs for Systems A and B.

The MaxAmp A/B setting determines what model of current transducer has been connected tothe AKC 24W3 amperage inputs at AI 1 and AI 2.A setting of zero means no transducer is being used. A setting of 200 means that the trans-ducer range will not exceed 200 amps.A setting of 400 means that the transducer range will not exceed 400 amps.

It is possible to configure the sensor S7 to measure, and display on the AKA 21 setting module(or AKM software installed on a P.C), a number of different texts, dependent on which mediathe sensor is used to measure. The different modes are:

S7 Mode = 0 No Sensor connected to the S7 input, NO display on the AKA 21 or AKM.S7 Mode = 1 LvgCond C is displayed against the S7 input.S7 Mode = 2 EntCond C is displayed against the S7 input.S7 Mode = 3 EntAirTemp is displayed against the S7 input.S7 Mode = 4 MixLvgTemp is displayed against the S7 input.

When the Entering Air Temperature is measured, (S7 Mode = 3), and it is less than 5°C, thetime delayed low pressure time-out is extended by a defined number of times, this number oftimes being determined by the setting EntAirMult. If EntAirMult = 4, then if the standard TDLPtime out is 60 seconds, the low ambient temperature time-out will be extended by four times to240 seconds. This means that a chiller operating in a low ambient air temperature less than5°C will be given longer to get away at start up without risking a TDLP trip than would other-wise be the case.

NOTE:When using AKM software, it will be necessary to upload a new parameter list every time theS7 Mode is changed for the new sensor description text to be updated to the current setting.

The four pressure inputs PoA, PoB, PcA and PcB are filtered by a low pass filter with a variabletime constant. The time constant can be set within the range 1 to 20 seconds.

NOTE:All temperature inputs are filtered with a fixed time constant of 1 second.

Ext.Max K.

Amp.Inp A/B

MaxAmp A/B

S7 Mode

Filtering of pressuresignals - Tau sec


Output ConfigurationThis menu contains all the output configuration including compressor and fan control.

This menu allows the type of compressor, the number of capacity stages of that compressor,the loading status of the unloaders (for reciprocating compressors), the lead/lag status of thecompressors, the loading/unloading behaviour (for reciprocating compressors), and the typeof pulse mode (for screw compressors), to be set.

Reciprocating / Screw selectionThe Recip/Screw setting defines whether the compressor is reciprocating (or scroll) type, orscrew type. The setting is 1 for reciprocating compressors and 2 for screw compressors.Reciprocating compressors are controlled by cut in and cut out of steps, and screw compres-sor by step-less controlled pulsed loading and unloading compressor slide valve.

Maximum number of steps for each compressor - Max Step A/BThis setting determines the maximum number of unloading stages that are fitted to the SystemA or System B compressor.

The controller can operate up to six compressor steps distributed on one or two compressors.The compressor steps must be defined in two groups, so that the controller will know whichsteps belong to compressor A and which belong to compressor B.Note that there is difference in defining the steps with AKC24W3 compared to AKC24W/2. Thedigital output DO1 output is dedicated permanently to circuit A, and DO2 output is dedicatedpermanently to circuit B. Max Step setting means literally the number for each circuit.

Example:

gnitteSstuptuO

ArosserpmoC BrosserpmoC

5htiwrosserpmocenO*spets

5=ApetSxaM0=BpetSxaM

4OD,3OD,1OD6OD,5OD

--

2htiwsrosserpmocowTspets


3OD,1OD 4OD,2OD

4htiwsrosserpmocowTspets2dna


5OD,4OD,3OD,1OD 6OD,2OD

* This is maximum number of steps for one compressor.

NOTE:When Recip/Screw = 2 (screw compressor), the Max Step values for A and B are automaticallyset to 3.

Output Mode - OutputThe Output setting applies only to reciprocating compressors having cylinder or blockedsuction unloading solenoid valves.If Output is set to 1, the controller outputs to the solenoid coils will be energised to load thecompressor. If set to 2, the outputs connected to the solenoid coils will be de-energised to loadthe compressor.

Time ShareThe Time Share sets the lead and lag compressor. The alternative settings are:

Time Share = 1 Compressor A is the LeadTime Share = 2 Compressor B is the LeadTime Share = 3 The Lead compressor is the opposite to the one that ran last.

NOTE:For automatic compressor rotation (i.e. automatic lead/lag changeover), the setting shouldTime Share = 3.

The Compressor configu-ration


Step ModeFor dual System reciprocating compressor chillers, the setting Step Mode allows to set up theloading and unloading behaviour of the compressors, so that a machine can either start thelead compressor, then load it up, then start the lag compressor and load it up, or start the leadcompressor, start the lag compressor, and then load the lead compressor and lag compressorsequentially. It is also possible change the lead compressor during descending loads. Thisbehaviour can be displayed in letters where the - Max Step A/B is 3:

Step Mode = 1The cut in and cut out of capacity steps of compressors A and B are:StartA(DO 1)-LoadA1(DO 3)-LoadA2(DO 4)-StartB( DO 2)-LoadB1(DO 5)-LoadB2(DO 6).

Step Mode = 2The cut in and cut out of capacity steps in compressors A and B is for cut in:StartA(DO 1)-LoadA1(DO 3)-LoadA2(DO 4)-StartB( DO 2)-LoadB1(DO 5)-LoadB2(DO 6).

for cut out:UnloadB2(DO 6)-UnloadA2(DO 4)-UnloadB1(DO 5)-UnloadA1(DO 3)-StopB(DO 2)-StopA(DO 1).

Step Mode = 3The cut in and cut out of capacity of compressors A and B is:StartA(DO 1)-StartB(DO 2)-LoadA1(DO 3)-LoadB1( DO 5)-LoadA2(DO 4)-LoadB2(DO 6).

The step sequence will be in the same form for other set values of - Max Step A/B.

NOTE:The choice of which mode is best depends very much on the application. For optimum chillerefficiency, Step Mode = 1 is best, as it maintains a higher compressor loading during periodsof part load. However, if there is any tendency to low pressure tripping on a particular site, forexample where the chilled media strainer is partially blocked or the chilled media flow rate issignificantly reduced for any reason, the Service Engineer may decide to choose Step Mode =3. This will allow two compressors to run less fully loaded, thus reducing the tendency to timedelayed low pressure tripping during low loads. However, running two compressors unloadedis less efficient than running one compressor more fully loaded.

NOTE:Using Step Mode = 1, where each system has its own plate evaporator each having its ownchilled media circuit, will lead to mixed chilled media outlet temperatures. Using Step Mode =3 will minimise this tendency.

Pulse ModeThis setting applies to screw compressor machines, and allows the Service Engineer to seteither a fixed or variable pulse width mode. If Pulse Mode = 1, the pulse width of load/unloadpulses sent to the compressor load cylinder will be unaffected by variations in dischargepressure, such as may occur with air cooled chillers operating in a changing climate. If PulseMode = 2, the pulse width will vary according to whether the discharge/suction differentialchanges. A low differential will give longer pulses, while a higher differential will producesmaller pulses. This mode is meant to allow an AKC 24W3 equipped chiller to adapt itself tovarying ambient, and prevent a slide valve unloader of a screw compressor from sticking inone position temporarily at start up, or during rapid changes in load. This should also preventcontinued see-sawing of load then unload pulses.


Configuration of the DO1 to DO6 outputs for screw compressorsThe outputs DO1 to DO6 can be set to operate various types of screw compressors. This doneby setting the parameter ScrwOutRex in the Output Configuration AKM menu to a specificvalue. The factory setting for ScrwOutRex is 23904 which gives the following operation the DOoutputs:

)2OD(1OD )5OD(3OD )6OD(4OD

tratS 1 0 1

daoL 1 *gnisluP 0

daolnU 1 0 **gnisluP

dloH 1 0 0

potS 0 0 0

Another combination can be established by setting ScrwOutRex to 20328 which gives thefollowing operation:

)2OD(1OD )5OD(3OD )6OD(4OD

tratS 1 0 1

daoL 1 *gnisluP 1

daolnU 1 0 **gnisluP

dloH 1 0 1

potS 0 0 0

* The DO output is on t1 Pulse seconds for each Period s intervals (Loading).** The DO output is on t2 Pulse seconds for each Period s intervals (Unloading).Other combinations are possible, and can be offered on enquiry.

NOTE:INPUT and OUTPUT configuration is only possible when the Main Switch is set to Main Switch= 0. Customer enable set to off and Flow switch set to off.The user cannot change the configuration of a chiller while it is enabled to run.


Service Menu

Service Mode is used in connection with installation, service and trouble-shooting on thesystem. With this function, the connected functions can be checked, e.g. temperature sensors,pressure transmitters, digital inputs and alarms.

It is possible to measure the AKC 24W3 controller input in Service Menu, while a chiller isrunning. These include the following:

SucPres A b......... Suction Pressure, System A, in bar.SucPres B b......... Suction Pressure, System B, in bar.DscPres A b......... Discharge Pressure, System, A in bar.DscPres A b......... Discharge Pressure, System B, in bar.S2A °C................ Suction Temperature, System A in °C.S2B °C.............… Suction Temperature, System B in °C.S3 °C..............…. Entering Chilled Media Temperature, in °C.S4 °C................... Leaving Chilled Media Temperature, in °C.S7 °C................... Configurable Temperature Sensor Value, in °CExt.Ref. V............ The voltage level present on the Chilled Media Temperature Reset

Input.CurrentA V.......... The voltage level being supplied by the current transducer on

Amperage Input A IA.CurrentB V.......... The voltage level being supplied by the current transducer on

Amperage Input AIB.Safety A............... The status of the digital input to which are connected System A

external safety devices.Safety B............... The status of the digital input to which are connected System B

external safety devices.FlowSwitch.......... The status of the flow switch contacts: no flow or flow present.UnitEnable........... The status of the customer’s unit enable signal: low = off, high = on.

It is possible to measure the AKC 24W3 output parameters while a chiller is running. Theseinclude the following:

AKV A %......... The opening percentage of the AKV valve serving System A, if any.AKV B%.......... The opening percentage of the AKV valve serving System B, if any.DO1.................. The status of digital output 1, the on/off output for Compressor A.DO2.................. The status of digital output 2, the on/off output for Compressor B.DO9.................. The station of digital output 9, the “enable next chiller” output.Alarm Rel1....... The status of the digital output signalling an Alarm is present on System A.Alarm Rel2....... The status of the digital output signalling an Alarm is present on System B.Analogue A......... The value in percent of the Analogue output signal on AOI (Fan Output A).Analogue B.......... The value in percent of the Analogue output signal on AO2 (Fan Output B).

Measurement of Inputs

Measurement of Inputs


This menu allows the AKC 24W3 controller outputs to be switched manually ON/OFF for faultfinding purposes.

Man.CtrlTo use this service function, two settings have to be made:

1. The MainSwitch is set to -1(This will trigger an alarm message “Standby mode” to indicate that regulation hasstopped, and that all outputs are in position OFF.

2. The Man.Ctrl function is set to ON (the default setting is OFF). This setting is only effective ifthe controller mode has been set to Main Switch = - 1.The individual outputs can now be controlled manually.

NOTE:There is no regulation when the Main Switch is in position “-1” (or position “0”).

AKV A%This setting allows the opening percentage of the AKV electronic expansion valve connectedto System A, which can be set to a certain figure between 0% and 100%. It is useful to deter-mine that the chiller has been wired so that the solenoid coil fitted to the System A AKV valvehas been wired to the AKV A output of the AKC 24W3 controller.

AKV B%This setting allows the opening percentage of the AKV electronic expansion valve connectedto System B which can be set to a certain figure between 0% and 100%. It is useful to deter-mine that the chiller has been wired so that the solenoid coil fitted to the System B AKV valvehas been wired to the AKV B output of the AKC 24W3 controller.

DO 1This setting allows the System A Compressor ON/OFF digital output to be toggled ON or OFF.This is useful for checking that the starting systems for System A are operative before a firststart of the chiller.

DO 2This setting allows the System B Compressor ON/OFF digital output to be toggled ON or OFF.This is useful for checking that the starting systems for System B are operative before a firststart of the chiller.

DO 3.....DO9This setting allows the “Capacity Step” digital output to be toggled ON or OFF.

AlarmRel.1This setting allows the Alarm Relay for System A to be tested for correct function.

AlarmRel.2This setting allows the Alarm Relay for System B to be tested for correct function.

NOTE:The AKC 24W3 Alarm Outputs have a reversed functionality to most other controllers bymanufacturers other than Danfoss. When no alarm exists, the output relay contact is closed.When an alarm exists, this relay contact will be open.

Force Control of Outputs


Analogue AThis setting allows the percentage of maximum analogue output voltage on the System A fanoutputAO 1 to any value between 0% and 100%, which controls the voltage output range 0 to 10Volts.The setting is useful for the checking the correct staging of fans for different levels of dischargepressure, or to check the variable speed drive of the fan motors.It is also useful for the proper electrical testing of chiller control circuits, (in particular the fanwiring), prior to the first starting of a chiller.

Analogue BThis setting allows the percentage of maximum analogue output voltage on the System B fanoutputAO 2 to any value between 0% and 100%, which controls the voltage output range 0 to 10Volts.The setting is useful for the checking to see the correct staging of fans for different levels ofdischarge pressure, or to check the variable speed drive of the fan motors. It is also useful forthe proper electrical testing of chiller control circuits, (in particular the fan wiring), prior to thefirst starting of a chiller.


System Measurements/data

Functions and measurements pertaining to the refrigeration system can be shown on thecontrol panel’s display or on the PC screen by the system software type AKM.Displayed temperatures are indicated in °C (or C) or K, and digital functions with ON and OFF.

AKA 21 operationA display with ***** indicates that there is a defective sensor or that a sensor has not beenmounted.

Compressor regulationSucPres A b......... Suction Pressure, System A, in bar.SucPres B b......... Suction Pressure, System B, in bar.Run A h/10......... Compressor A accumulated run time in hours.Run B h/10......... Compressor B accumulated run time in hours.MediaSlope........... The rate of change of the Leaving water temperature in K/s.S2B °C.............… Suction Temperature, System B in °C.EntMedia C........... Entering Chilled Media Temperature, in °C.LvgMedia C........... Leaving Chilled Media Temperature, in °C.S7 °C................... Configurable Temperature Sensor Value, in °CRef. °C.............. The Chilled Media Temperature Reference.A compr. A .......... The voltage level being supplied by the current transducer on

Amperage Input A IA.B compr. A.......... The voltage level being supplied by the current transducer on

Amperage Input AIB.Safety A............... The status of the digital input to which are connected System A

external safety devices.Safety B............... The status of the digital input to which are connected System B

external safety devices.A compr. %.......... The actual cut in capacity for compressor A (reciprocating only).B compr. %.......... The actual cut in capacity for compressor B (reciprocating only).

Injection control A and BSucSHeat K......... The actual superheat.SH ref K......... Superheat reference.EvapTemp......... Evaporator temperature converted from evaporator pressure.SucTemp C............. Suction Temperature, °C.AKV OD %.......... The opening percentage of the AKV valve.

Condenser regulation for A and BDscPres b......... Discharge Pressure, System, A in bar.CondTemp........... This is the condenser* temperature calculated from the discharge

pressure.Fan %.............…. Entering Chilled Media Temperature, in °C.CondSlope............. The rate of change of the condenser temperature K/s.

* This is not the actual condenser temperature but only converted from discharge temperature.

Constant updatingIf constant display of a menu is required, e.g. temperature value , the display panel can belocked to the menu.Procedure: Show the required menu on the display, push the ENTER key for three seconds.The function is cancelled by pushing one of the arrow keys.

PC operationIn addition to the earlier described measurements with control panel type AKA 21, it is with theoperation from a PC, also possible to define the importance of various alarms. Read section“Alarms and messages”.


Alarms and messages

In connection with the controller’s function, there are a number of alarms and messages whichbecome visible in case of fault or incorrect operation.

The distinction is made between important information and not so important information. Thedegree of importance is factory set, but can be changed as required.

1. “Alarms”This is important information from the controller.· The controller’s alarm output is activated.· Information is transmitted on the DANBUSS network together with status 1.· If a gateway type AKA 243/244 is connected and it is defined as master, its relay output

DO 2 will be activated for two minutes (AKA 243/244 with software version 2.0 or later)· Later, when the alarm is discontinued, the same information will be repeated, but this

time with status value 0.

2. “Messages”This is less important information from the controller.· The information is transmitted on the DANBUSS network together with status 2.· Later, when the “message” is discontinued, the same information will be repeated but

this time with status 0.

3. “Alarms”As “1”, but DO 2 output on a master gateway will not be activated.

0. “Suppressed information”This information stops at the controller. It is not transmitted anywhere.

In the latter case, the alarm sent to the DANBUSS has lowest priority, (i.e. Priority 2).

When an alarm is sent to the Alarm Output, the controller decides which of the two controlleralarm outputs is appropriate for the type of alarm being generated, by using the followingAlarm Destination Code scheme:

Code = 0 Alarm is not sent to either Alarm Output Relay A or B.Code = 1 Alarm is sent to Alarm Output Relay A only.Code = 2 Alarm is sent to Alarm Output Relay B only.Code = 3 Alarm is sent to both Alarm Output Relays A and B.

NOTE:The AKC 24W3 controller is not fitted with a Common Alarm output. Instead, it has two alarmrelay outputs, one for each System, A and B. It is therefore necessary for the controller to knowwhich of the relays is appropriate for a given alarm condition. To generate a Common Alarm,the two output relays must be connected to another relay, such that they are connected inparallel. If either Alarm Relay Output A or B registers an alarm, the external relay will provide aCommon Alarm output signal.


List of alarm activities:

mralAecnatropmi

sutatSmralA3W42CKA

*syalermrala3W42CKA

DELmralA12AKA

DEL442/342AKA

yaler2OD

0mralA FFO sehsalF sehsalF .nim2FFO

mralAoN NO FFO FFO NO

1mralA NO sehsalF sehsalF NO


2mralA FFO sehsalF sehsalF NO

mralAoN NO NO FFO NO

3mralA NO FFO FFO NO


* See explanation of AKC 24W3 above.

There are two Alarm Destinations sub-menus, one covering “Sensor Alarms”, and one cover-ing “Other Alarms”. These are described below.

NOTE:It is common for all alarms listed here to be allocated Priority = 1.

Sensor Alarms

The following Sensor Alarms will be registered:

noitacifitnedimralA ytiroirP edoCnoitanitseDyaleRmralA

AmetsySerusserProtaropavE.....AoP 1 1

BmetsySerusserProtaropavE......BoP 1 2

AmetsySerusserPresnednoC......AcP 1 1

BmetsySerusserPresnednoC......BcP 1 2

AerutarepmeTteltuOrotaropavE.....A2S 1 1

BerutarepmeTteltuOrotaropavE.....B2S 1 2

AerutarepmeTaideMdellihCgniretnE.........3S 2 3

BerutarepmeTaideMdellihCgnivaeL.........4S 1 3

rosneSerutarepmeTelbarugifnoC.........7S 2 3

egnarfotuoegatloVteseRaideMdellihC.......feR.txE 1 3


Other Alarms

The following Other Alarms will be registered

noitacifitnedimralA ytiroirP edoCnoitanitseDyaleRmralA

AdnoChgiH 1 1

BdnoChgiH 1 2

AtcuswoL 1 1

BtcuswoL 1 2

wolfwoL 1 3

torPtsorF 1 3

aidemhgiH 1 3

AtratsoN 1 1

ApotsoN 1 1

BtratsoN 1 2

BpotsoN 1 2

APLyaleD 1 1

BPLyaleD 1 2

APL 1 1

BPL 1 2

AHSwoL 1 1

BHSwoL 1 2

AytefaS 1 1

BytefaS 1 2

A.serPffiD 1 1

B.serPffiD 1 2

doMybdnatS 2 3

epyT.gfR 1 3

Lockout Alarms

Some of the alarms have been installed for the operational safety of the chillers and will causethe affected circuit to lockout in the event of any of these alarms. The affected circuit cannot berestarted before the alarm condition has recovered and the manual reset has been made. Themanual reset is found in the Main Function Menu in the Manual Rest of Vital alarms menu.The following is a list of the Lockout Alarms

mralA egasseMmralA

)B/A(tluafrosnes0P "B/AtluaFrosnes.serPnoitcuS"

)B/A(tluafrosnescP "B/AtluaFrosneS.serPresnednoC"

)B/A(tluafrosnes2S "B/AtluaFrosneS.pmeTnoitcuS"

B/AdnoChgiH "B/AerusserPgnisnednoChgiH"

B/AtcuswoL "B/AerusserPnoitcuswoL"

torPtsorF "noitcetorPtsorF"

"erutarepmeTaideMhgiH"´

B/AtratSoN "B/AtrtatSoNrosserpmoC"

B/APLyaleD "B/AevitcAmralAPLyaleDemiT"

B/AytefaS "B/AmralA.tcCytefaSlanretxE"

B/A.serPffiD "B/AsserP.ffiD)tcus-csiD(woL"


Access code

The controller can be operated with system software type AKM and control panel type AKA21.Both operating modes may give access to several levels, depending on the user’s knowl-edge of the various functions.

System software type AKM:The different users are defined here with initials and passwords. Access is now granted toexactly the functions the user is allowed to operate.The operation is described in the AKM manual.

Control Panel type AKA 21:Access can be given to two user levels here:1. Access without use of password

Can see all information in the To F1, F2 and F3 functions, and can reset alarms in F1.2. Access via code 1.

Full access to all menus.

If access code is set in position “0” (factory setting), there is free access to the system withoutthe use of a password.


AKM Menu description

#0Main menu’s Main Functions

MEASUREMENTS SETTINGSAKC Error MainSwitchConditions Man. ResetSuc.SH A KEv.A TempCSuc.SH B KEv.B TempCRfg.Type R

#1 #2Capacity Ctrl. Injection Ctrl. A

MEASUREMENTS SETTINGS MEASUREMENTS SETTINGSAKC Error MainSwitch AKC Error MainSwitchCondition Cap.Ctrl. Condition Inj Ctrl ASuc.SH A K LvgMedia C Suc.SH A K MOPEv.A TempC +NZ K Ev.A TempC MOP °CSuc.SH B K -NZ K Suc.SH B KEv.B Temp C HiPreSet b Ev.B TempCMediaSlope LoPreSet b Inj.StateARef. °C t1 pulse s SH ref.A KEntmedia °C t2 pulse s SucTempA CEvapAppA K RunTimeA h AKV OD %EvapAppB K RunTimeB hS7 NotUsed Media Al °CSafety A DO9 Set °CSafety B DO9 Diff K A compr. AB compr. A

SucPresA bSucPresB bA Compr. %B Compr. %

AlarmsMain FunctionCapacity Ctrl.Injection Ctrl.AInjection Ctrl.BExtended capacity CtrlExtended injection Ctrl.A Extended injection Ctrl.BFan A ControlFan B ControlInput ConfigurationOutput ConfigurationService modeAlarm destinationsI/O Allocation


#3 #4Injection Ctrl.B Extended capacity Ctrl

MEASUREMENTS SETTINGS MEASUREMENTS SETTINGSAKC Error MainSwitch AKC Error MainSwitchCondition Inj Ctrl B Condition +Time sSuc.SH A K MOP Suc.SH A K -Time sEv.A TempC MOP °C Ev.A TempC ++Time sSuc.SH B K Suc.SH B K +Zone KEv.B TempC Ev.B TempC -Zone KInj.StateB --Time sSH ref.B K Slope Td sSucTempB C RTimeA minAKV OD % RTimeB min

MinOff A mMinOff B mFst.PeriodFst.PulseTrans.Dly.

Period s Imax A Amp Imax B Amp deltaA % deltaB % I delay s

+Rate K/m-Rate K/m++Rate K/mNoStop AmpNoStop secNoRun secLagOn minLagStopRngCOP TimerPO OnStartPO OS barLPhold barTD LP barLPDly secTD LP OFFEntAirMultLP Cut barDisSucAbarDisSucBbarAmp.Inp.AMaxAmps AAmp.Inp.BMaxAmps B


#5 #6Extended injection Ctrl.A Extended injection Ctrl.B

MEASUREMENTS SETTINGS MEASUREMENTS SETTINGSAKC Error MainSwitch AKC Error MainSwitchConditions SHcloseA K Conditions SHcloseB KSuc.SH A K Shmin A K Suc.SH A K Shmin B KEv.A TempC Shmax A K Ev.A TempC Shmax B KSuc.SH B K AKV max % Suc.SH B K AKV max %Ev.B TempC PWM A s Ev.B TempC PWM B s

LowSH dly LowSH dlyLowSH Alm LowSH AlmKp min A Kp min BKp max A Kp max BKpPo A KpPo BTn A Tn BAdapMode A AdapMode B

#7 #8Fan A Control Fan B Control

MEASUREMENTS SETTINGS MEASUREMENTS SETTINGSAKC Error MainSwitch AKC Error MainSwitchCondition Fan A Ctrl Condition Fan B CtrlSuc.SH A K Dsc A SP C Suc.SH A K Dsc B SP CEv.A TempC +Zone K Ev.A TempC +Zone KSuc.SH B K -Zone K Suc.SH B K -Zone KEv.B TempC Slope Td s Ev.B TempC Slope Td sDscTempA C HPCOutA °C DscTempB C HPCOutB °C DscPresA b HP UnLdA K DscPresB b HP UnLdB KFan A % HP HoldA K Fan B % HP HoldB KCondSlopeA Tn A CondSlopeB Tn B

#9 #10Input Configuration Output Configuration

MEASUREMENTS SETTINGS MEASUREMENTS SETTINGSAKC Error MainSwitch AKC Error MainSwitchCondition Ref.Type Condition Recip/ScrewSuc.SH A K Limit Sens Suc.SH A K Max step AEv.A TempC Ext.Ref. Ev.A TempC Max step BSuc.SH B K Ext.Max. K Suc.SH B K OutputEv.B TempC S7 Mode Ev.B TempC ScrwOutReXRfg.Type R Tau sec Time share

Step modePulse mode


#11 #12Service Mode Alarm Destinations

MEASUREMENTS SETTINGS MEASUREMENTS SETTINGSAKC Error MainSwitch AKC Error MainSwitchCondition Man. Ctrl. Condition NetworkSuc.SH A K AKV A % Suc.SH A K HighCond.AEv.A TempC AKV B % Ev.A TempC HighCond.BSuc.SH B K DO 1 Suc.SH B K Low suct AEv.B TempC DO 2 Ev.B TempC Low suct BSucPresA b DO 3 Low flowSucPresB b DO 4 FrostProt.DscPresA b DO 5 High MediaDscPresB DO 6 No Start AS2A °C DO 9 No Start BS2B °C AlarmRel.1 No Stop AS3 °C AlarmRel.2 No Stop BS4 °C Analog A Delay LP AS7 °C Analog B Delay LP BExt.ref.V LP ACurrentA V LP BCurrentB V Low SH ASafety A Low SH BSafety B Safety AFlowSwitch Safety BUnitEnable DiffPres.AAKV A % DiffPres.BAKV B % StandbyModDO 1 Low flowDO 2 Ref.TypeDO 3 PoADO 4 PoBDO 5 PcADO 6 PcBDO 9 S2 AAlarmRel.1 S2 BAlarmRel.2 S3Analog A S4Analog B S7

Ext.Ref


#13I/O Allocations

MEASUREMENTS SETTINGSAKC Error MainSwitchCondition SRDTSuc.SH A K ConfigLockEv.A TempC HighCond.BSuc.SH B K -InjAPoFilEv.B TempC -InjBPoFil

Def.RelayA MEASUREMENTS SETTINGSRelay A0 V AKC Error MainSwitch

Relay A1 V Condition Relay A2 V Suc.SH A K Relay A3 V Ev.A TempC Relay A4 V Suc.SH B K Relay A5 V Ev.B TempC

Relay A6 VDef.RelayBRelay B0 VRelay B1 VRelay B2 VRelay B3 VRelay B4 VRelay B5 VRelay B6 VRfg.Fac.a1Rfg.Fac.a2Rfg.Fac.a3HighCond.AHighCond.BLow suct ALow suct BLow flowFrostProt.High MediaNo Start ANo Start BNo Stop ANo Stop BDelay LP ADelay LP BLP ALP BLow SH ALow SH BSafety ASafety BDiffPres.ADiffPres.BStandbyModLow flowRef.TypePoAPoBPcAPcBS2 AS2 BS3S4S7Ext.Ref

#10 is equal to task 10schaded cells are common parameters


AKA 21 Menu description for Screw Compressors

AKC24W3 Adr: Code No.084B2043

Mon hh:mm Prog.Ver. 1.20

Clock: Clock: Day

MON-00:00 (Mon)1 (Sun)7

System addr. Clock: Hour

Addr. yyy:xxx 0 23 0

Alarm report to Clock: Min.


Gateway Add.

xxx

Chg. Code1

0 255 0

Main Function Main Switch MainSwitch

Ctrl(1)/Serv(2) -1 1 0

Manual Reset of RESET

vital alarms OFF ON OFF

Rfg. Fac.a1

*****32766 0

Rfg. Fac.b1

*****32766 0

Rfg. Fac.c1

*****32766 0

Main Switch:1: Control mode0: Stop-1 Service mode

Possibility:Password on AKA21 (Danset), like AKC1xx

Refrigeration constants:Rfg.Fac.a1, Rfg.Fac.b1 and Rfg.Fac.c1 can be set via AKM in the Dunham-Bush only Menu.

Reset Switch:If one of the circuits stops due to LPCU, NoRun, NoStop or HPCO, then manual reset is necessary before start


Capacity Ctrl. Cap.Measurements Condition 000

Cap.Settings Cap.Ctrl. Cap.Ctrl. OFF

OFF ON OFF

Adv. Capacity Period s LvgMedia C LvgMedia C 0.0

Settings 5 900 120 -99,9 99,9 6,0

ImaxA Amp MediaAl °C MediaSlope -0.1

0 600 250 -50.0 99.9 10,0

deltaA % Limit °C EntMedia C 0.0

1 10 8 -99,9 50,0 1,0

ImaxB Amp +NZ K EvapAppA K 0.0

0 600 250 0. 1 20 1.0

deltaB % -NZ K EvapAppB K 0.0

1 10 8 0. 1 20 1.0

I Delay s +Zone K Ref. °C 0,0

0 300 30 0.2 10 5.0

LagOn min 60 -Zone K Limit °C 0,0

0 90 60 0.2 10 5.0

LagStopRng 4.0 t1 pulse s S7 °C 0.0

0.1 10.0 3.0 0.1 3.0 5 (see S7 Mode)

COP Timer 300 t2 pulse s Safety A OFF

60 900 300 0.1 3.0 5

Fst.Period 5 Safety B OFF

1 20 10

Fst.Pulse 10 Run A h/10 0

1 20 10

Trans.Dly 60 Run B h/10 0

1 60 20

HiPreSet 20 A compr. A 0.0

1.0 30.0 20.0

LoPreSet 10 B compr. A 0.0

1.0 12.0 10

+Rate K/m SucPresA b 2.7

-10.0 0.0 -1.0

-Rate K/m SucPresB b 2.7

0.1 10.0 1.0

++Rate K/m

-10.0 0.0 -1.0

-Time sec

10 9999 60

--Time sec

5 9999 30

DO9 Set°C

-99.9 99.9 15.0

DO9 Diff K

1.0 10.0 5.0

Current Limiting:The screw compressor motorcurrent is reduced by amountdelta % after reaching the limitImax (Amp), followed by atime delay I Delay (sec).

S7 Mode display select:0: no display.1: text "LvgCond C" displayed.2: text "EntCond C" displayed.3: text "EntAirTemp" displayed.4: text "MixLvgTemp" displayed.(see Input Configuration for setting)


Safety Controls NoStop Amp 50

0 100 50

NoRun sec 60

0 90 60

NoStop sec 30

0 90 30

LagDly min 30

0 90 30

RTimeA min 30

1 60 30

MinOff A m 1

1 60 1

RTimeB min 30

1 60 30

MinOff B m 1

0 60 1

PO OnStart OFF

OFF ON OFF

LPHold bar 3.8

-1.0 4.0 3.8

TD LP bar 3.5

-1.0 4.0 3.5

LPDly sec 60

0 300 60

TDLPOFF 3

1 10 3

EntAirMult 4

1 10 4

PO OS bar 3.0

1.0 4.0 3.0

LP Cut bar 2.0

-1.0 4.0 2.0

DisSucAbar 2.1

-5.0 5.0 2.1

DisSucBbar 2.1

-5.0 5.0 2.1

Low suction pressure condition handling:LPHO: Low Pressure Hold Set point.TDLP: Time Delayed Low Pressure Cut out Set pt.POOnStart: Pump Out On Start Set point.LPCO: Low Pressure Cut Out Set point.

Pump Out On Start:OFF: disabledON: enabled

Delays and Timers:NoStop: The No stop alarm delay time.NoRun: The No start alarm delay time.LagDly: The lag time before comp B starts.ARTime: AntiCycle timer. LPDly: The delay before LP cut out.


Injection Ctrl. A Inj.Measurements Inj.StateA 0

Inj.Settings Inj Ctrl.A SucSHeat K 0,0

OFF ON OFF

Adv. Inject. SHcloseA K MOP SH ref. A K 3.0

Settings 0 10 2 OFF ON OFF

SHminA K MOP °C EvapTemp C 0,0

1 11 4 -40.0 40.0 0.0

SHmaxA K SucTempA C 0.0

5 20 10

AKV max % AKV OD % 0

5 100 100

PWM A s 3

2 6 3

LowSH dly 180

0 300 180

LowSH Alm OFF

OFF ON OFF

Injection Ctrl. B Inj.Measurements Inj Ctrl.B OFF

Inj.Settings Inj Ctrl.B

Adv. Inject.

Settings

Low Superheat alm:When superheat is less thanShclose, one step is cut out and compressor is not allow to load till after delay LowSH dly

Note:SucSHeat: DN standard is S2-S1.EvapTemp: DN standard is PO/S1.SucTemp: DN standard is S2.SucPres: DN standard PO.


Fan A Control Fan A CondTempA 0,0

measurement

Fan A Fan A Ctrl DscPresA b 0,0

settings OFF ON OFF

DscA SP °C Fan A % 0

-50 120 120

+Zone K CondSlopeA 0.1

0. 1 20 2.0

-Zone K

0. 1 20 2,0

Slope Td s 5

5 60 5

HPCOutA °C

-50 120 120

HPUnLdA K

-20.0 0.0 -2.0

HPHOldA K

-20.0 0.0 -4.0

Tn A

20 300 120

Fan B Control Fan B

measurement

Fan B

settings

High Pressure Limits:HPCOut: High Pressure Cut Out set point (°C).HPUnLd: High Pressure Unload set point (Degrees K under HPCOut).HPHold: High Pressure Hold set point (Degrees K under HPCOut)


INPUT Comp.Cap. Rfg. Type R 0

Configuration

Rfg. Type

0 23 0

Limit Sens

0 5 2

Ext.Ref.

1 2 1

Ext.Max. K

-50 50 0

Amp.Inp. A

1 2 1

MaxAmps A 200

0 400 200

Amp.Inp. B

1 2 1

MaxAmps B 200

100 400 200

S7Mode 1

0 4 0

OUTPUT Comp.Cap. Recip/Screw

Configuration 1 2 2

Max Step A

0 6 3

Max Step B

0 5 3

Output 1

1 2 1

Time share

1 3 3

Step mode 1

1 3 1

Pulse mode 2

1 2 2

Note:INPUT and OUTPUT Configuration is only posible when Ext.Main is OFF (open circuit)

No output for alarm relay!!

Output: (DO1 - DO6)1: energized2: de-energized

Ext.Ref.:1: 0-10 Volt2: 2-10 Volt

Current Transducer: 2 Volts = 0 Amp. 10 Volts = Max Amp.

Step Mode:1: S - L - L - S - L - L2: Same as Mode 2 AKC24W2.3: S - S - L - L - L - L

Rfg.Type:1: R122: R223: R134a4: R5025: R7176: R137: R13b18: R239: R50010: R50311: R11412: R142b

14: R32 15: R22716: R401A17: R50718: R402A19: R404A20: R407C21: R407A22: R407B23: R410A

Limit Sens:0: no sensor.1: S3.2: S4.3: PoA.4: PoB.5: Smallest value of PoA/PoB.

Pulse Mode:1: Fixed t1(t2) pulses2: Variable t1(t2) pulses

Compressor Type:1: Reciprocating2: Screw


Service Mode Measurements of SucPresA b 1,00

Inputs

Measurement of AKV A % SucPresBb 1,00

Outputs

Manual Control Man.Ctrl. AKV B % DscPresA b 1,00

of Outputs OFF ON OFF

AKV A % DO1 DscPresB b 1,00

0 100 0

AKV B % S2 A °C 0,0

0 100 0 DO6

DO1 S2 B °C 0,0

OFF ON OFF DO9

S3 °C 0,0

DO6 AlarmRel.1

OFF ON OFF S4 °C 0,0

DO9 AlarmRel.2


AlarmRel.1 Analog A

OFF ON OFF Ext.ref.. V 0,0

AlarmRel.2 Analog B

OFF ON OFF CurrentA V 0,0

Analog A

0.0 10.0 0 CurrentB V 0,0

Analog B

0.0 10.0 0 Safety A OFF

Safety B OFF

FlowSwitch OFF

UnitEnable OFF


Alarm Sensors PoA 1

destinations Alarms 0 3 1

Other HighCond.A 1 PoB 1

Alarms 0 3 1 0 3 1

HighCond.B 1 PcA 1

0 3 1 0 3 1

Low suct A 1 PcB 1

0 3 1 0 3 1

Low suct B 1 S2 A 1

0 3 1 0 3 1

Low flow 1 S2 B 1

0 3 1 0 3 1

FrostProt. 1 S3 1

0 3 1 0 3 1

High media 1 S4 1

0 3 1 0 3 1

No start A 1 S7 1

0 3 1 0 3 1

No stop A 1 Ext.Ref 1

0 3 1 0 3 1

No start B 1

0 3 1

No stop B 1

0 3 1

Delay LP A 1

0 3 1

Delay LP B 1

0 3 1

LP A 1

0 3 1

LP B 1

0 3 1

Low SH A 1

0 3 1

Low SH B 1

0 3 1

Safety A 1

0 3 1

Safety B 1

0 3 1

DiffPres.A 1

0 3 1

DiffPres.B 1

0 3 1

StandbyMod 1

0 3 1

Rfg. Type 1

0 3 1


Menu for F1, F2 and F3 soft keys

F1 F2 F3

No Alarms FlowSwitch ON Media Al °C 30.0

UnitEnable ON Limit °C 3.0

Cap.Ctrl. ON SHmaxA K 8.0

See Alarm List PO OS bar ON SHminA K 4.0

Safety A OFF SHmaxB K 8.0

Safety B OFF SHminB K 4.0

A Compr. % 100 SHcloseA K 2.0

B Compr. % 100 MOP °C

EntMedia C 0.0 SHcloseB K 2.0

LvgMedia C 0.0 MOP °C

SucPresA b 3.0 HP HoldA K 4.0

DscPresA b 3.0 HP UnLdA K 2.0

SucPresB b 3.0 HP HoldB K 4.0

DscPresB b 3.0 HP UnLdB K 2.0

SucPresA C 2.7 LPHold bar 3.8

Suc.SH A K 3.0 LP Cut bar 3.0

SucPresB C 2.7 HPCOutA °C 40.0

Suc.SH B K 3.0 HPCOutB °C 40.0

Zone-A-B TDLP bar 1.0

Condition 000 LPCO bar 0.8

+NZ K 1.0

-NZ K 1.0

+Zone K 3.0

-Zone K 3.0

+Rate K/m -0.5

+Time s 90

++Rate K/m -1.0

++Time s 60

-Rate K/m -0.5

-Time s 90

-Rate K/m -0.5

--Time s 90

RTimeA min 15

MinOff A m 30

RTimeB min 15

MinOff B m 30

F1 Key:This menu includes all the alarms which are active or have become inactive.

F2 and F2 Keys:F2 is the readings for daily userF3 is intended for checking the set points. The changing of the set points is done in the normal


Alarm message

The following display read-outs are only visible if there is an active error.

When the error is corrected, the Alarm message can be removed by pressing ENTER.

Alarm message Cause

Suction Pres. Faulty PoA pressure

Sensor Fault A transmitter

Suction Pres. Faulty PoB pressure

Sensor Fault B transmitter

Condensing Pres. Faulty PcA pressure


Condensing Pres. Faulty PcB pressure


Suction Temp. Faulty S2A sensor

Sensor Fault A

Suction Temp. Faulty S2B sensor

Sensor Fault B

S3 Error Faulty S3 sensor



High Condensing Too high condensing

Pressure B pressure in cct. A


Pressure A pressure in cct. B

Low Suction Too low suction

Pressure A pressure A


Pressure B pressure B

Low Media Flow / Low flow alarm due to

Pump Failure DI4 switch is off

Frost Frost protection alarm

Protection

High Media Overheat alarm

Temperature

Compressor No start alarm for

No Start A compressor A

Compressor No stop alarm for

No Stop B compressor A


No Start B compressor B


No Stop B compressor B

Time Delay LP Time delayed low pressure

Alarm Active A alarm for cct A.


Alarm Active B alarm for cct B.

Low Suction Low superheat alarm for

Superheat A cct A - less than Sh_close


Superheat B cct B - less than Sh_min

External Safety External safety switch

Cct. Alarm A connected to DI1


Cct. Alarm B connected to DI2

Low (Disc-Suct) Low suction/discharge

Diff. Pres. A differential alarm - for screw A

Low (Disc-Suct) Low suction/discharge

Diff. Pres. B differential alarm - for screw B

Standby mode Regulation has

stopped

Rfg. Type The refrigerant type has not been

Not selected selected.

Rfg. Type change Refrigerant type has been changed

after pow_up after power up

External Ref. Fault with the external reference.

Alarm Alarm function only applicable for a 2 to 10 V signal.


AKA 21 Menu description for Reciprocating Compressors

AKC24W3 Adr: Code No.084B2043

Mon hh:mm Prog.Ver. 1.20

Clock: Clock: Day

MON-00:00 (Mon)1 (Sun)7

System addr. Clock: Hour


Alarm report to Clock: Min.


Gateway Add.

xxx

Chg. Code1

0 255 0

Main Function Main Switch MainSwitch

Ctrl(1)/Serv(2) -1 1 0

Manual Reset of RESET

vital alarms OFF ON OFF

Rfg. Fac.a1

*****32766 0

Rfg. Fac.b1

*****32766 0

Rfg. Fac.c1

*****32766 0

Main Switch:1: Control mode0: Stop-1 Service mode

Possibility:Password on AKA21 (Danset), like AKC1xx

Refrigeration constants:Rfg.Fac.a1, Rfg.Fac.b1 and Rfg.Fac.c1 can be set via AKM in the Dunham-Bush only Menu.

Reset Switch:If one of the circuits stops due to LPCU, NoRun, NoStop or HPCO, then manual reset is necessary before start


Capacity Ctrl. Cap.Measurements Condition 000

Cap.Settings Cap.Ctrl. Cap.Ctrl. OFF

OFF ON OFF

Adv. Capacity +Time sec LvgMedia C LvgMedia C 0.0

Settings 10 900 120 -99,9 99,9 6,0

-Time sec MediaAl °C MediaSlope -0.1

10 9999 60 -50,0 99,9 10,0

++Time sec Limit °C EntMedia C 0.0

5 300 30 -99,9 50,0 1,0

--Time sec +NZ K EvapAppA K 0.0

5 9999 30 0. 1 20 1.0

+Rate K/m -NZ K EvapAppB K 0.0

-10.0 0.0 -1.0 0. 1 20 1.0

-Rate K/m +Zone K Ref. °C 0,0

0.0 10 1.0 0.2 10 5.0

++Rate K/m -Zone K Limit °C 0,0

-10.0 0.0 -1.0 0.2 10 5.0

S7 °C 0.0

(see S7 Mode)

A compr. % 0

B compr. % 0

Safety A OFF

Safety B OFF

Run A h/10 0

Run B h/10 0

A compr. A 0.0

B compr. A 0.0

SucPresA b 2.7

SucPresB b 2.7

S7 Mode display select:0: no display.1: text "LvgCond C" displayed.2: text "EntCond C" displayed.3: text "EntAirTemp" displayed.4: text "MixLvgTemp" displayed.(see Input Configuration for setting)


Safety Controls NoStop Amp 50

0 100 50

NoRun sec 60

0 90 60

NoStop sec 30

0 90 30

RTimeA min 30

0 60 30

MinOff A m 1

1 60 1

RTimeB min 30

0 60 30

MinOff B m 1

0 60 1

PO OnStart OFF

OFF ON OFF

LPHold bar 3.8

-1.0 4.0 3.8

TD LP bar 3.5

-1.0 4.0 3.5

LPDly sec 60

0 300 60

TDLPOFF 3

1 10 3

EntAirMult 4

1 10 4

PO OS bar 3.0

1.0 4.0 3.0

LP Cut bar 2.0

-1.0 4.0 2.0

DisSucAbar 2.1

-5.0 5.0 2.1

DisSucBbar 2.1

-5.0 5.0 2.1

Low suction pressure condition handling:LPHO: Low Pressure Hold Set point.TDLP: Time Delayed Low Pressure Cut out Set pt.POOnStart: Pump Out On Start Set point.LPCO: Low Pressure Cut Out Set point

Pump Out On Start:OFF: disabledON: enabled

Delays and Timers:NoStop: The No stop alarm delay time.NoRun: The No start alarm delay time.LagDly: The lag time before comp B starts.ARTime: AntiCycle timer. LPDly: The delay before LP cut out.


Injection Ctrl. A Inj.Measurements Inj.StateA 0

Inj.Settings Inj Ctrl.A SucSHeat K 0,0

OFF ON OFF

Adv. Inject. SHcloseA K MOP SH ref. A K 3.0

Settings 0 10 2 OFF ON OFF

SHminA K MOP °C EvapTemp C 0,0

1 11 4 -40.0 40.0 0.0

SHmaxA K SucTempA C 0.0

5 20 10

AKV max % AKV OD % 0

5 100 100

PWM A s 3

2 6 3

LowSH dly 180

0 300 180

LowSH Alm OFF

OFF ON OFF

Injection Ctrl. B Inj.Measurements Inj Ctrl.B OFF

Inj.Settings Inj Ctrl.B

Adv. Inject.

Settings

Low Superheat alm:When superheat is less thanShclose, one step is cut out and compressor is not allow to load till after delay LowSH dly

Note:SucSHeat: DN standard is S2-S1.EvapTemp: DN standard is PO/S1.SucTemp: DN standard is S2.SucPres: DN standard PO.


Fan A Control Fan A DscTempA 0,0

measurement

Fan A Fan A Ctrl DscPresA b 0,0

settings OFF ON OFF

DscA SP °C Fan A % 0

-50 120 120

+Zone K CondSlopeA 0.1

0. 1 20 2.0

-Zone K

0. 1 20 2,0

Slope Td s 5

5 60 5

HPCOutA °C

-50 120 120

HPUnLdA K

-20.0 0.0 -2.0

HPHOldA K

-20.0 0.0 -4.0

Tn A

20 300 120

Fan B Control Fan B

measurement

Fan B

settings

High Pressure Limits:HPCOut: High Pressure Cut Out set point (°C).HPUnLd: High Pressure Unload set point (Degrees K under HPCOut).HPHold: High Pressure Hold set point (Degrees K under HPCOut).


INPUT Comp.Cap. Rfg. Type R 0

Configuration

Rfg. Type

0 23 0

Limit Sens

0 5 2

Ext.Max. K

-50 50 0

Amp.Inp. A

1 2 1

MaxAmps A 200

0 400 200

Amp.Inp. B

1 2 1

MaxAmps B 200

100 400 200

S7Mode 1

0 4 0

OUTPUT Comp.Cap. Recip/Screw

Configuration 1 2 1

Max Step A

0 6 3

Max Step B

0 5 3

Output 1

1 2 1

Time share

1 3 3

Step mode 1

1 3 1

Pulse mode 2

1 2 2

Note:INPUT and OUTPUT Configuration is only posible when Ext.Main is OFF (open circuit)

No output for alarm relay!!

Output: (DO1 - DO6)1: energized2: de-energized

Ext.Ref.: (AKM only)1: 0-10 Volt2: 2-10 Volt

Current Transducer: 2 Volts = 0 Amp. 10 Volts = Max Amp.

Step Mode:1: S - L - L - S - L - L2: Same as Mode 2 AKC24W2.3: S - S - L - L - L - L

Rfg.Type:1: R122: R223: R134a4: R5025: R7176: R137: R13b18: R239: R50010: R50311: R11412: R142b

14: R32 15: R22716: R401A17: R50718: R402A19: R404A20: R407C21: R407A22: R407B23: R410A

Limit Sens:0: no sensor.1: S3.2: S4.3: PoA.4: PoB.5: Smallest value of PoA/PoB.

Pulse Mode:1: Fixed t1(t2) pulses2: Variable t1(t2) pulses

Compressor Type:1: Reciprocating2: Screw


Service Mode Measurements of SucPresA b 1,00

Inputs

Measurement of AKV A % SucPresBb 1,00

Outputs

Manual Control Man.Ctrl. AKV B % DscPresA b 1,00

of Outputs OFF ON OFF

AKV A % DO1 DscPresB b 1,00

0 100 0

AKV B % S2 A °C 0,0

0 100 0 DO6

DO1 S2 B °C 0,0

OFF ON OFF DO9

S3 °C 0,0

DO6 AlarmRel.1


DO9 AlarmRel.2


AlarmRel.1 Analog A

OFF ON OFF Ext.ref. V 0,0

AlarmRel.2 Analog B

OFF ON OFF CurrentA V 0,0

Analog A

0.0 10.0 0 CurrentB V 0,0

Analog B

0.0 10.0 0 Safety A OFF

Safety B OFF

FlowSwitch OFF

UnitEnable OFF


Alarm Sensors PoA 1

destinations Alarms 0 3 1

Other HighCond.A 1 PoB 1

Alarms 0 3 1 0 3 1

HighCond.B 1 PcA 1

0 3 1 0 3 1

Low suct A 1 PcB 1

0 3 1 0 3 1

Low suct B 1 S2 A 1

0 3 1 0 3 1

Low flow 1 S2 B 1

0 3 1 0 3 1

FrostProt. 1 S3 1

0 3 1 0 3 1

High media 1 S4 1

0 3 1 0 3 1

No start A 1 S7 1

0 3 1 0 3 1

No stop A 1 Ext.Ref 1

0 3 1 0 3 1

No start B 1

0 3 1

No stop B 1

0 3 1

Delay LP A 1

0 3 1

Delay LP B 1

0 3 1

LP A 1

0 3 1

LP B 1

0 3 1

Low SH A 1

0 3 1

Low SH B 1

0 3 1

Safety A 1

0 3 1

Safety B 1

0 3 1

DiffPres.A 1

0 3 1

DiffPres.B 1

0 3 1

StandbyMod 1

0 3 1

Rfg. Type 1

0 3 1


Menu for F1, F2 and F3 soft keys

F1 F2 F3

No Alarms FlowSwitch ON Media Al °C 30.0

UnitEnable ON Limit °C 3.0

Cap.Ctrl. ON SHmaxA K 8.0

See Alarm List PO OS bar ON SHminA K 4.0

Safety A OFF SHmaxB K 8.0

Safety B OFF SHminB K 4.0

A Compr. % 100 SHcloseA K 2.0

B Compr. % 100 MOP °C

EntMedia C 0.0 SHcloseB K 2.0

LvgMedia C 0.0 MOP °C

SucPresA b 3.0 HP HoldA K 4.0

DscPresA b 3.0 HP UnLdA K 2.0

SucPresB b 3.0 HP HoldB K 4.0

DscPresB b 3.0 HP UnLdB K 2.0

SucPresA C 2.7 LPHold bar 3.8

Suc.SH A K 3.0 LP Cut bar 3.0

SucPresB C 2.7 HPCOutA °C 40.0

Suc.SH B K 3.0 HPCOutB °C 40.0

Zone-A-B TDLP bar 1.0

Condition 000 LPCO bar 0.8

+NZ K 1.0

-NZ K 1.0

+Zone K 3.0

-Zone K 3.0

+Rate K/m -0.5

+Time s 90

++Rate K/m -1.0

++Time s 60

-Rate K/m -0.5

-Time s 90

-Rate K/m -0.5

--Time s 90

RTimeA min 15

MinOff A m 30

RTimeB min 15

MinOff B m 30

F1 Key:This menu includes all the alarms which are active or have become inactive.

F2 and F2 Keys:F2 is the readings for daily userF3 is intended for checking the set points. The changing of the set points is done in the normal menus.



No Start A compressor A


No Stop B compressor A


No Start B compressor B


No Stop B compressor B


Alarm Active A alarm for cct A.


Alarm Active B alarm for cct B.


Superheat A cct A - less than Sh_close


Superheat B cct B - less than Sh_min


Cct. Alarm A connected to DI1


Cct. Alarm B connected to DI2

Alarm message

The following display read-outs are only visible if there is an active error.

When the error is corrected, the Alarm message can be removed by pressing ENTER.

Alarm message Cause

Suction Pres. Faulty PoA pressure


Suction Pres. Faulty PoB pressure


Condensing Pres. Faulty PcA pressure


Condensing Pres. Faulty PcB pressure


Suction Temp. Faulty S2A sensor

Sensor Fault A

Suction Temp. Faulty S2B sensor

Sensor Fault B





Pressure B pressure in cct. A


Pressure A pressure in cct. B


Pressure A pressure A


Pressure B pressure B

Low Media Flow / Low flow alarm due to

Pump Failure DI4 switch is off

Frost Frost protection alarm

Protection

High Media Overheat alarm

Temperature



RC

-ET

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 productsalready on order provided that such alternations can be made without subsequential changes being necessary in specifications already agreed.All trademarks in this material are property of the respecitve companies. Danfoss and Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

Controller for capacity regulation - AKC 24W3 - …files.danfoss.com/TechnicalInfo/Dila/01/rc8aj302.pdf · Controller for capacity regulation - AKC 24W3 ... High pressure cut out

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