Time
Temper.
FnC=C_Y, fans will switch ON and OFF with the compressor and run during defrost.
Digital controller with defrost and fan management
XR44CX
1. GENERAL WARNING ........................................................................................................... 1
2. GENERAL DESCRIPTION .................................................................................................... 1
3. CONTROLLING LOADS ....................................................................................................... 1
4. FRONT PANEL COMMANDS ............................................................................................... 1
5. MAX & MIN TEMPERATURE MEMORIZATION .................................................................... 1
6. MAIN FUNCTIONS ................................................................ ............................................... 2
7. PARAMETERS ..................................................................................................................... 2
8. DIGITAL INPUTS .................................................................................................................. 3
9. TTL SERIAL LINE – FOR MONITORING SYSTEMS ............................................................. 3
10. INSTALLATION AND MOUNTING ......................................................................................... 3
11. ELECTRICAL CONNECTIONS.............................................................................................. 3
12. USE THE HOT KEY.............................................................................................................. 3
13. ALARM SIGNALS ................................................................................................ ................. 3
14. TECHNICAL DATA ............................................................................................................... 4
15. CONNECTIONS ................................ ................................................................................... 4
16. DEFAULT SETTING VALUES ............................................................................................... 4
FnC=o_Y, fans will run continuously also during defrost.
An additional parameter FSt provides the setting of temperature, detected by the evaporator probe,
above which the fans are always OFF. This is used to make sure circulation of air only if his
temperature is lower than set in FSt.
3.4.1 Forced activation of fans
This function managed by the FCt parameter is designed to avoid short cycles of fans, that could
happen when the controller is switched on or after a defrost, when the room air warms the evaporator.
How it works: if the temperature difference between evaporator probe and room probe is higher than
the FCt parameter value, fans will be switched on. With FCt=0 the function is disabled.
3.4.2 Cyclical activation of the fans with compressor off.
When FnC=C-n or C-Y (fans working in parallel with the compressor), by means of the Fon and FoF
parameters the fans can carry out on and off cycles even if the compressor is switched off. When the
compressor is stopped the fans go on working for the Fon time. With Fon=0 the fans remain always
off, also when the compressor is off.
4. FRONT PANEL COMMANDS
1. GENERAL WARNING
1.1 PLEASE READ BEFORE USING THIS MANUAL
This manual is part of the product and should be kept near the instrument for easy and quick
reference.
The instrument shall not be used for purposes different from those described hereunder. It
cannot be used as a safety device.
Check the application limits before proceeding.
Dixell Srl reserves the right to change the composition of its products, even without notice,
ensuring the same and unchanged functionality.
1.2 SAFETY PRECAUTIONS
Check the supply voltage is correct before connecting the instrument.
Do not expose to water or moisture: use the controller only within the operating limits avoiding
sudden temperature changes with high atmospheric humidity to prevent formation of
condensation
Warning: disconnect all electrical connections before any kind of maintenance.
Fit the probe where it is not accessible by the End User. The instrument must not be opened.
In case of failure or faulty operation send the instrument back to the distributor or to “Dixell S.r.l.”
(see address) with a detailed description of the fault.
Consider the maximum current which can be applied to each relay (see Technical Data).
Ensure that the wires for probes, loads and the power supply are separated and far enough
from each other, without crossing or intertwining.
In case of applications in industrial environments, the use of mains filters (our mod. FT1) in
parallel with inductive loads could be useful.
KEY COMBINATIONS:
To display target set point; in programming mode it selects a parameter or confirm
an operation.
(DEF) To start a manual defrost.
(UP) To see the max stored temperature; in programming mode it browses the
parameter codes or increases the displayed value.
(DOWN) To see the min stored temperature; in programming mode it browses the
parameter codes or decreases the displayed value.
To switch the instrument on and off (when onF=oFF).
To switch on and off the light output (if present).
+
To lock & unlock the keyboard.
2. GENERAL DESCRIPTION
Model XR44CX, format 32 x 74 mm, is microprocessor based controller, suitable for applications on
low temperature refrigerating units. It has four relay outputs to control compressor 1 and 2, defrost 1
and 2, which can be either electrical or reverse cycle (hot gas). It is also provided with up to three
NTC or PTC probe inputs, the first one for temperature control, the second and third one, to be
located onto the evaporator, to control the defrost termination temperature on the evaporator 1 and 2.
It allows to program the controller by means the HOT KEY programming keyboard.
3. CONTROLLING LOADS
3.1 COMPRESSOR
The regulation is performed according to
the temperature measured by the
thermostat probe with a positive
differential from the set point: if the
temperature increases and reaches set
point plus differential the compressor is
started and then turned off when the
temperature reaches the set point value
again.
In case of fault in the thermostat probe the start and stop of the compressor are timed through
parameters Con and CoF.
3.2 SECOND COMPRESSOR MANAGEMENT
The relay of the second compressor is activated in parallel with the relay of the first compressor, with
a possible delay set in the AC1 parameter. Both the compressors are switched off at the same time.
3.3 DEFROST
Two defrost modes are available through the tdF parameter: defrost through electrical heater
(tdF=EL) and hot gas defrost (tdF=in).
Other parameters are used to control the interval between defrost cycles (idF), its maximum length
(MdF) and two defrost modes: timed or controlled by the evaporator’s probe (P2P).
At the end of defrost dripping time is started, its length is set in the Fdt parameter. With Fdt=0 the
dripping time is disabled.
3.4 CONTROL OF EVAPORATOR FANS
The fan control mode is selected by means of the FnC parameter:
FnC=C_n, fans will switch ON and OFF with the compressor and not run during defrost.
FnC=o_n, fans will run even if the compressor is off, and not run during defrost.
After defrost, there is a timed fan delay allowing for drip time, set by means of the Fnd parameter.
1598024001 XR44CX ISA GB r2.0 21.06.2012.doc XR44CX 1/4
SET
Compr.
ON
+
+
4.1 USE OF LEDS
Each LED function is described in the following table.
LED MODE FUNCTION
ON Compressor enabled
Flashing Anti-short cycle delay enabled
ON Defrost enabled
Flashing Drip time in progress
ON
ON
ON Measurement unit
°C/°F
Flashing Programming phase
5. MAX & MIN TEMPERATURE MEMORIZATION
5.1 HOW TO: SEE THE MIN TEMPERATURE
1. Press and release the DOWN key.
2. The “Lo” message will be displayed followed by the minimum temperature recorded.
3. By pressing the DOWN key again or by waiting 5 sec the normal display will be restored.
5.2 HOW TO: SEE THE MAX TEMPERATURE
1. Press and release the UP key.
2. The “Hi” message will be displayed followed by the maximum temperature recorded.
3. By pressing the UP key again or by waiting 5 sec the normal display will be restored.
5.3 HOW TO: RESET THE MAX AND MIN TEMPERATURE RECORDED
1. Keep the SET key pressed more than 3 sec, while the max or min temperature is displayed.
(“rSt” message will be displayed)
2. To confirm the operation the “rSt” message will start blinking and the normal temperature will be
displayed.
To enter in programming mode.
To return to the room temperature display.
An alarm is occurring
Continuous cycle is running
6. MAIN FUNCTIONS
6.1 HOW TO: SEE THE SET POINT
1. Push and immediately release the SET key: the display will show the Set
point value.
2. Push and immediately release the SET key or wait for 5 sec to display
the probe value again.
6.2 HOW TO CHANGE THE SET POINT
1. Push the SET key more than 2 sec to change the Set point value.
2. The value of the set point will be displayed and the “°C” or “°F” LED will start blinking.
3. To change the Set value push the UP or DOWN arrows within 10 sec.
4. To save the new set point value, push the SET key again or wait for 10 sec.
6.3 HOW TO START A MANUAL DEFROST
Push the DEF key for more than 2 sec and a manual defrost will start.
6.4 HOW TO: CHANGE A PARAMETER VALUE
To change a parameter value, operate as follows:
1. Enter the Programming mode by pressing the SET+DOWN buttons for 3s (the °C or °F LED will
start blinking).
2. Select the required parameter. Press the SET button to display its actual value.
3. Use UP or DOWN buttons to change its value.
4. Press SET button to store the new value and move to the following parameter.
To exit: Press SET + UP buttons or waiting for 15s without pressing any key.
NOTE: the set value is stored even when the procedure is exited by waiting for the time-out to expire.
6.5 THE HIDDEN MENU
The hidden menu includes all the parameters of the instrument.
6.5.1 HOW TO: ENTER THE HIDDEN MENU
1. Enter the Programming mode by pressing the SET+DOWN buttons for 3 sec (the °C or °F LED
will start blinking).
2. Released the buttons and then push again the SET+DOWN buttons for more than 7s. The Pr2
label will be displayed immediately followed from the HY parameter.
Now it is possible to browse the hidden menu.
3. Select the required parameter.
4. Press the SET button to display its value.
5. Use UP or DOWN to change its value.
6. Press SET to store the new value and move to the following parameter.
To exit: Press SET+DOWN or wait 15 sec without pressing a key.
NOTE1: if no parameter is present in Pr1 menu, after 3 sec the “noP” message will be displayed.
Keep the buttons pushed till the Pr2 message will be displayed.
NOTE2: the set value is stored even when the procedure is exited by waiting for the time-out to
expire
6.5.2 HOW TO: MOVE A PARAMETER FROM THE HIDDEN MENU TO THE
FIRST LEVEL AND VICEVERSA.
Each parameter present in the hidden menu (Pr2) can be moved into the user level (Pr1) by pressing
SET+DOWN buttons. If a parameter is part of the user level, when showed in the hidden menu the
decimal point will be lit.
6.6 HOW TO: LOCK THE KEYBOARD
1. Keep both UP and DOWN buttons pressed for more than 3 sec.
2. The “PoF” message will be displayed and the keyboard will be locked. At this point it will be
possible only to see the set point or the MAX o Min temperature stored
3. If a button is pressed more than 3 sec the “PoF” message will be displayed
6.7 HOW TO: UNLOCK THE KEYBOARD
Keep pressed together for more than 3 sec the UP and DOWN keys till the “Pon” message will be
displayed.
6.8 THE CONTINUOUS CYCLE
When defrost is not in progress, it can be activated by holding the UP key pressed for about 3 sec.
The compressor operates to maintain the CCS set point for the time set through the CCt parameter.
The cycle can be terminated before the end of the set time using the same activation key UP for 3
sec.
6.9 THE ON/OFF FUNCTION
With “onF = oFF”, pushing the ON/OFF key, the instrument is switched off. The “OFF”
message is displayed. In this configuration, the regulation is disabled.
WARNING: Loads connected to the normally closed contacts of the relays are always
supplied and under voltage, even if the instrument is in stand by mode.
To switch the instrument on, push again the ON/OFF key.
7. PARAMETERS
REGULATION
HY Differential: (0.1 to 25.5°C; 1 to 45°F) intervention differential for set point.
Compressor Cut IN is Set Point + differential (HY). Compressor Cut OUT is when the
temperature reaches the set point.
LS Minimum set point: (-55°C to SET; -67°F to SET) sets the minimum value for the set
point.
US Maximum set point: (SET to 150°C; SET to 302°F) set the maximum value for set
point.
ot Thermostat probe calibration: (-12.0 to 12.0°C; -21 to 21°F) allows to adjust possible
offset of the thermostat probe.
P2P First evaporator probe presence: (n; Y) n = not present, the defrost stops by time;
Y = present, the defrost stops by temperature.
oE First evaporator probe calibration: (-12.0 to 12.0°C; -21 to 21°F) allows to adjust
possible offset of the evaporator probe.
P3P Second evaporator probe presence (P3): (n; Y) n = not present, the terminals
operate as digital input; Y = present, the terminals operate as third probe.
o3 Second evaporator probe calibration (P3): (-12.0 to 12.0°C; -21 to 21°F) allows to
adjust possible offset of the third probe.
odS Outputs activation delay at start up: (0 to 255min) this function is enabled at the
initial start up of the instrument and inhibits any output activation for the period of time
set in the parameter.
AC Anti-short cycle delay for first compressor: (0 to 50 min) minimum interval between
the compressor stop and the following restart.
AC1 Anti-short cycle delay for second compressor: (0 to 50 min) minimum interval
between the compressor stop and the following restart.
CCt Compressor ON time during continuous cycle: (0.0 to 24h00min, res. 10 min)
allows to set the length of the continuous cycle. Compressor stays on without
interruption during CCt time. This is useful, for instance, when the room is filled with
new products.
CCS Set point for continuous cycle: (-55 to 150°C; -67 to 302°F) it sets the set point
used during the continuous cycle.
Con Compressor ON time with faulty probe: (0 to 255min) time during which the
compressor is active in case of faulty thermostat probe. With Con=0 compressor is
always OFF.
CoF Compressor OFF time with faulty probe: (0 to 255min) time during which the
compressor is OFF in case of faulty thermostat probe. With CoF=0 compressor is
always active.
DISPLAY
CF Temperature measurement unit: (°C; °F) °C = Celsius; °F = Fahrenheit.
WARNING: When the measurement unit is changed the SET point and the values of
the parameters HY, LS, US, ot, ALU and ALL have to be checked and modified (if
necessary).
rES Resolution (for °C): (in=1°C; dE=0.1°C) allows decimal point display.
Lod Instrument display: (P1; P2, P3, P4, SET, dtr) it selects which probe is displayed by
the instrument. P1 = Thermostat probe; P2 = Evaporator probe; P3 = Third probe (only
for model with this option enabled); P4 = Fourth probe, SET = set point; dtr =
percentage of visualization.
DEFROST
tdF Defrost type: (EL; in) EL = electrical heater; in = hot gas.
dtE First defrost termination temperature: (-55 to 50°C; -67 to 122°F) (enabled only
when EdF=Pb) sets the temperature measured by the evaporator probe, which causes
the end of defrost.
dtS Second defrost termination temperature: (-55 to 50°C; -67 to 122°F) (enabled only
when EdF=Pb) sets the temperature measured by the evaporator probe, which causes
the end of defrost.
idF Interval between defrost cycles: (0 to 120 hours) determines the interval of time
between two defrost cycles.
MdF (Maximum) length for first defrost: (0 to 255 min) when P2P=n, (not evaporator
probe: timed defrost) it sets the defrost duration. When P2P=Y (defrost end based on
temperature) it sets the maximum length for defrost.
MdS (Maximum) length for second defrost: (0 to 255 min) when P2P=n, (not evaporator
probe: timed defrost) it sets the defrost duration. When P2P=Y (defrost end based on
temperature) it sets the maximum length for defrost.
dSd Start defrost delay: (0 to 99 min) this is useful when different defrost start times are
necessary to avoid overloading the plant.
dFd Temperature displayed during defrost: (rt; it; SEt; dEF) rt = real temperature;
it = temperature at defrost start; SEt = set point; dEF = “dEF” label.
dAd MAX display delay after defrost: (0 to 255 min) sets the maximum time between the
end of defrost and the restarting of the real room temperature display.
Fdt Drip time: (0 to 120 min) time interval between reaching defrost termination
temperature and the restoring of the control’s normal operation. This time allows the
evaporator to eliminate water drops that might have formed due to defrost.
dPo First defrost after start-up: (n; Y)
n = after the idF time,
dAF Defrost delay after continuous cycle: (0.0 to 24h00min, res. 10min) time interval
FANS
FnC Fans operating mode: (C-n; o-n; C-Y; o-Y) C-n = runs with the compressor, OFF
Fnd Fans delay after defrost: (0 to 255min) interval between end of defrost and evaporator
FCt Temperature differential to avoid fan short cycles: (0 to 59°C; 0 to 90°F) (N.B.: if
FSt Fans stop temperature: (-55 to 50°C; -67 to 122°F) setting of temperature, detected
ALARMS
ALU MAXIMUM temperature alarm:
Y = immediately.
between the end of the fast freezing cycle and the following defrost related to it.
during defrost; o-n = continuous mode, OFF during defrost; C-Y = runs with the
compressor, ON during defrost; o-Y = continuous mode, ON during defrost.
fans start.
FCt=0 function disabled) if the difference of temperature between the evaporator and
the room probes is higher than FCt value, the fans will be switched on.
by evaporator probe, above which fans are always OFF.
If ALC=Ab: [ALL to 150.0°C or ALL to 302°F]
If ALC=rE: [0.0 to 50.0°C or 0 to 90°F]
when this temperature is reached the alarm is enabled, after the ALd delay time.
1598024001 XR44CX ISA GB r2.0 21.06.2012.doc XR44CX 2/4
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