A. Introduction
B. Hardware Description
C. Control Actions
D. Control Board – LCD & LED
E. Description of Inputs / Outputs
F. Keypad
G. Regulation of Room Temperature
H Setting the parameters
I. Technical Data
Introduction
The “MEGA CHILL-3Comp” is a three compressor chiller controller . This
integrates all the required functions of the chiller.
It is very user friendly due to the LCD provided which gives all the parameters,
messages, alarms etc on the display. In addition to the LCD there are LED’s
provided for instant status on all controls in the system.
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HARDWARE DESCRIPTION
The basic system comprises :
-Control (Display) board
-INPUT/OUTPUT board
WARNING :
HP, LP, Antifreeze faults are by default in manual reset mode. They remain in manual
reset mode until the user resets to normal conditions by pressing the CLEAR button.
These can be changed to auto reset by changing P4 parameter.
CONTROL ACTIONS
-Regulation of Chiller temperature based on the control sensor location.
Control Board :
LIQUID CRYSTAL DISPLAY (LCD)
The Liquid Crystal Display shows the values of the controlled parameters, the selected
set-point, the alarm thresholds and all other information concerning the controlled
variables.
DISPLAY types :
2 rows X 16 characters LCD
LIGHT EMITTING DIODES (LED)
LEDs INDICATING THE STATUS OF THE DEVICES
There are different LED indications on the control board front panel. They give the
following information :
-Red blinking LED “ALERT” : Indicates that there is a fault
-Red LED devices : Indicates that there is a fault in that particular device
-Green LED devices : Indicates that the device is OK
-Blank (inactive) LED indicates that the device is inactive.
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DESCRIPTION OF INPUTS / OUTPUTS
ANALOGUE INPUTS
Probes
1. CONTROL : used as the main controlling probe based on which the setpoint will
regulate the system.
2. Condenser Inlet : Senses Condenser Inlet temperature
4. Water Inlet : Senses Water (CHILLER) Inlet temperature
5. Water Outlet : Senses Water (CHILLER) Outlet temperature
6. Antifreeze : Used to trip compressors below AFT set point .
DIGITAL INPUTS
Controller manages the following protections :
-High Pressure trip for the compressor1(HP1)
-Low Pressure Trip for the compressor1.(LP1)
-Compressor Overload trip1(COMP O/L1)
-OSS - Oil Safety Switch (OSS1)
-Single Phase Preventor Trip1(SPP1)
-High Pressure trip for the compressor2(HP2)
-Low Pressure Trip for the compressor2.(LP2)
-Compressor Overload trip2(COMP O/L2)
-OSS - Oil Safety Switch (OSS2)
-Single Phase Preventor Trip2(SPP2)
-High Pressure trip for the compressor3(HP3)
-Low Pressure Trip for the compressor3.(LP3)
-Compressor Overload trip3(COMP O/L3)
-OSS - Oil Safety Switch (OSS3)
-Single Phase Preventor Trip3(SPP3)
-Condenser Fan1 O/L Trip (FAN O/L1 )
-Condenser Fan2 O/L Trip (FAN O/L2 )
-Condenser Fan3 O/L Trip (FAN O/L3 )
-Pump Overload Trip
-Evaporator Water Flow Switch Trip
The controller informs the user of a fault condition via a buzzer and an ALARMRELAY.
DIGITAL OUTPUTS (RELAY)
1.Chiller Pump
2.Compressor1
3.Condenser Fan1
4.Compressor2
5.Condenser Fan2
6.Compressor3
7.Condenser Fan3
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8.Water SV
9.Alarm
10.Pumpdwn SV1
11.Pumpdwn SV2
12.Pumpdwn SV3
KEYPAD
START
Press and hold this key for 4 seconds to bring the controller in an operative status from
the stand-by status in which it normally is after being powered on except if H2 parameter
is set to AUTOSTART mode.
STOP
Press and hold this key for 4 seconds to stop the system and operate in Stand By mode.
MUTE
Press this key for 1 second, to disable the buzzer and alarm relay.
RESET
Press and hold this key for 4 seconds to reset HP,LPand antifreeze alarms which have
been set for MANUAL RESET incase P4 parameter is set to MANUALRESET mode.
TEMP
Press and hold this key for 1 seconds to display temperatures for all probes. Use up/down
key to scroll through the various probes attached. To exit this mode, press the temp key.
PRG, SEL, UP & DWN
Used to enter programming mode.
REGULATION OF CHILLER TEMPERATURE
The regulation of the Brine temperature is based on the CONTROL probe.
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SET-POINT AND DIFFERENTIAL
Set-point is the temperature at which the chiller temperature has to be regulated, at which
time the compressor will go off. Differential is the temperature added after which the
compressor restarts. For example, if Set-point is 7oC and differential is 2oC, then
compressor will switch off at 7 oC and restart at 7+2 = 9oC.
*******ALARMS*******
Incase of all alarms corresponding LCD readouts and LED signals will display,and the
system will act accordingly. For example if there is an HP1 error, Compressor1 will trip
and restarts with the time delay.
PARAMETER SETTINGS :
All “working” parameters are protected with a hardware key to prevent any
unauthorized access to the data. Press PRG + SEL for more than 5 seconds to enter the
parameter mode. To change any parameter PROKEY must be inserted before entering to
the programming mode.
Display will flash parameter “t1” . Using UP/DOWN key user can scroll all the
parameters . By pressing “SEL” key user can view and change respective parameter
value. Press PRG to store and exit from that particular parameter. To End
Programming press SEL key when LED display shows EP
If you do not press any button within 20 seconds after having entered this
procedure, the unit will return to normal operation without storing the values of the
modified parameters.
Setting and displaying set parameters.
ParaProbeSet byMinMaxFac.M.UVariation
Control Probe calibration.
It may so happen that during the course of
time there may be a slight offset in the actual
temperature and the temperature shown. For
T1
example if the actual temperature is 20 oC
U-10100
o
C0.5
and the temperature on the controller shows
22 oC, set this parameter to -2 oC and once out
of this mode, the temperature will display 20
o
C (22-2 oC)
T2
Antifreeze probe calibration.
Setting as in T1.
R1Set point for compressor1UR4R310
R2Set point for compressor2UR4R37
U-10100
o
C0.5
o
C0.5
o
C0.5
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R3Set point for compressor3UR4R37.5
R4Differential for compressor1U1.010.02.0
R5Differential for compressor2U1.010.02.0
R6Differential for compressor3U1.010.02.0
Maximum Cooling Setpoint
Once set at a particular range, this will not
allow the set point to go above this range and
below R4 setting.
Example: Setting this parameter at 250Cwill
R7
not allow the set point to go above 250C.
FR65050
Also if the temperature reaches 250C the
display will show Ht (High Temp)
indicating that the temperature has gone
above the range in this parameter and at this
point the alarm will come on.
Minimum Cooling Setpoint
Use UP/DOWN keys to get desired range &
press set key to confirm.
Once set at a particular range, this will not
allow the set point to go below this range and
above R3 setting
R8
Example: Setting this parameter at -300C
F-30R5-30
will not allow the set point to go below
-300C. Also if the temperature reaches -300C
the display will show Lt (Low Temp)
indicating that the temperature has gone
below the range in this parameter and at this
point the alarm will come on.
Time delay for compressor1 restart
E.g. If this parameter is set at 3MIN,then
after cutting off the compresso1r at set
C1
temperature compressor1 will not
F0203Min1
Restart for a minimum of 3min.This time
delay is also active at power on of the system
.
Time delay for compressor2 restart
E.g. If this parameter is set at 3MIN,then
after cutting off the compressor2 at set
C2
temperature compressor2 will not
F0203Min1
Restart for a minimum of 3min.This time
delay is also active at power on of the system
.
Time delay for compressor3 restart
E.g. If this parameter is set at 3MIN,then
after cutting off the compressor3 at set
C3
temperature compressor3 will not
F0203Min1
Restart for a minimum of 3min.This time
delay is also active at power on of the system
.
C4Time delay between any two compressors
F012010Sec1
start.
o
C0.5
o
C0.5
o
C0.5
o
C0.5
o
C0.5
o
C0.5
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E.g. If this Parameter is set to 30sec ,then
second compressor will come on after 30sec
delay from first compressor switch on.
Fan Operating Mode
F1
0=Fan Always On
F010Flag1
1=Fan on with compressor
Starting Time of Fans
F2
Fans will start these many seconds before the
F012020Sec1
compressor starts .
AFT Probe Active
To activate Antifreeze(AFT) Probe
A1Antifreeze set point for AFT ProbeF-30R14
A2Differential for AFT ProbeF1102
Flow switch alarm delayed at power on.
P1
System will activate the alarm only if the
error persists for more than P1 secs at system
F01205Sec1
start up.
Flow Switch Alarm delay during normal
operation.
If this parameter is set at 10 seconds , the
P2
system will activate the flow switch alarm
F0905Sec1
only if the error persists for or more than 10
seconds .In this manner a false alarm can be
avoided during normal operation.
Low Pressure Alarm delayed during
compressor start up
o
C1
o
C1
If this parameter is set at 30 seconds , the
P3
system will activate the low pressure switch
alarm only if the error persists for or more
than 30 seconds .In this manner a false alarm
can be avoided due to low pressure at
compressor start up.
Reset of alarms.
0= Manual Reset for HP,OSS and AFT
P4
alarms
1= Auto Reset for HP,OSS and AFT alarms
PUMP Start Logic
PUMP with Comp
H0
It defines Pump working logic.
0= Pump Always On.
1= Pump On/Off with Comp.
H1To activate Pumpdown procedure
This parameter is used to activate or
deactivate pumpdown procedure at every
refrigeration cycle .
0 = Inactivate Pumpdown
F012040Sec1
F010Flag1
F010Flag1
F010Flag0
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H2
H3
H4
H5
H6
H7
FO
LP
FS
EP
1 = Activate Pumpdown
AUTOSTART on power on.
0=Standby on power on.
1=Autostart on power on.
Phase Errors
R Y B Phase Error
0= Inactive.
1= Active.
Incase of 0 system will ignore R Y B errors.
UNIT1 SELECTION
0= Unit1 Inactive
1= Unit1 Active
Incase of 0 system will not activate
compressor1 and all its faults.
UNIT2 SELECTION
0= Unit2 Inactive
1= Unit2 Active
Incase of 0 system will not activate
compressor1 and all its faults.
UNIT3 SELECTION
0= Unit3Inactive
1= Unit3 Active
Incase of 0 system will not activate
compressor1 and all its faults.
Fault in standby
It Enable/Disable fault sensing in standby
mode.
0 = Disable.
1 = Enable.
Fault sense logic of digital inputs
0 = Faults at 0V.
1 = Faults at 230V.
Keypad lock.
0= Keypad Active
1=Keypad Locked
Factory set parameters
1=Factory set parameters.
End programming mode.
Once in this mode press the SET key. The
controller goes into the normal mode and all
settings are saved.
F010Flag1
F011Flag1
F011Flag1
F011Flag1
F011Flag1
F010Flag1
F010Flag1
U010Flag1
F010Flag1
FFlag
Technical Specifications :
1. Analog Inputs : Japanese NTC thermistors
Resolution : 0.5 0C
Accuracy : +/- 10C
2. Controlling Temp. Range : -30 to 50 0C
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3. Digital Inputs : Potential Inputs 230Vac
4. Digital Output (Relay)
Rating : 230Vac, 8A (resistive) All digital outputs are fused