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1592009037 XW270-271L GB r1.0 15.12.2004.doc
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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.
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.p.A.” (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.
2.
GENERAL DESCRIPTION
Models XW270L and XW271L, 38x185 mm format, are microprocessor based controllers suitable for applications
on medium or low temperature refrigerating units. They are provided with six relay outputs to control compressor,
defrost - which can be either electrical or hot gas - the evaporator fans, the lights, the alarm and an auxiliary
output. In XW271L the auxiliary output is configured as anti-condensing heater.
They are also provided with three NTC probe inputs, one for temperature control, one to control the defrost end
temperature of the evaporator and the third, optional, for the display. There are two digital inputs (free contact) for
the door switch and configurable by parameter.
The standard TTL output allows the user to connect, by means of a TTL/RS485 external module, a ModBUS-
RTU compatible monitoring system and to programme the parameter list with the “Hot Key”.
An optional output for remote display “XW-REP” is available.
3.
CONTROLLING LOADS
3.1 THE 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 FAST FREEZING
When defrost is not in progress, it can be activated the keypad by holding the
9
9
key pressed for about 3
seconds. The compressor operates in continuous mode 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,
9
9
for about 3 seconds.
3.3 DEFROST
Three defrost modes are available through the “tdF” parameter: defrost with electrical heater, hot gas or
thermostatic defrost. The defrost interval is control by means of parameter “EdF”: (EdF=in) the defrost is made
every “IdF” time, (EdF=Sd) the interval “IdF” is calculate through Smart Defrost algorithm (only when the
compressor is ON and the evaporator temperature is bigger than “SdF” parameter).
At the end of defrost the drip time is controlled through the “Fdt” parameter.
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=C-y fans will run continuously, but not during defrost
After defrost, there is a timed fan delay allowing for drip time, set by means of the “Fnd” parameter.
FnC=O-n fans will switch ON and OFF with the compressor and run during defrost;
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 can be used to make sure circulation of air only if his temperature is lower than set
in “FSt”.
3.5 AUXILIARY OUTPUT
The auxiliary output is switch ON and OFF by means of the corresponding button on the keyboard.
The auxiliary output of the XW271L model controls the anti-condensing heater and it is automatically activated if
the room temperature is lower than the “SAA” parameter.
4.
KEYBOARD
))
&
To display and modify target set point; in programming mode it selects a parameter or confirm an
operation.
By holding it pressed for 3s when max or min temperature is displayed it will be erased.
To see the max. stored temperature; in programming mode it browses the parameter codes or
increases the displayed value. By holding it pressed for 3s the fast freezing cycle is started.
To see the min stored temperature; in programming mode it browses the parameter codes or
decreases the displayed value.
By holding it pressed for 3s the defrost is started.
Switch ON and OFF the cold room light.
By holding it pressed for 3s Energy Saving function is started or stopped.
For XW270L model. Switch ON and OFF the auxiliary output.
For XW271L model. Switch ON and OFF the anti-condensing heater output.
Switch ON and OFF the instrument.
KEY COMBINATIONS
+
To lock and unlock the keyboard.
+
To enter the programming mode.
+
To exit the programming mode.
4.1 USE OF LEDS
Each LED function is described in the following table.
LED
MODE
Function
ON
The compressor is running
FLASHING
- Programming Phase (flashing with LED
)
- Anti-short cycle delay enabled
ON
The fan is running
FLASHING
Programming Phase (flashing with LED
)
ON
The defrost is enabled
FLASHING
Drip time in progress
ON
The Fast Freezing cycle is enabled
ON
- ALARM signal
- In “Pr2” indicates that the parameter is also present in “Pr1”
ON
(Present only in ’XW271L)
The Anti-condensing heater relay (Aux) is ON.
Function of the LEDs placed on the left top side of buttons:
BUTTON
MODE
FUNCTION
SET
FLASHING
The Set point is displayed and it can be modified
SET
FAST FLASHING
The Energy Saving is enabled
DEFROST
ON
The Manual Defrost is activated
ENERGY SAVING
ON
The Energy Saving is enabled
LIGHT
ON
The Light is ON
AUX
ON
The Auxiliary output is ON (XW270L)
HEATER
ON
The Anti-condensing heater is ON (XW271L)
ON/OFF
ON
The instrument is OFF
4.2 HOW TO SEE THE MIN TEMPERATURE
1.
Press and release the
8
8
key.
2.
The “Lo” message will be displayed followed by the minimum temperature recorded.
3.
By pressing the
8
8
key or waiting for 5s the normal display will be restored.
4.3 HOW TO SEE THE MAX TEMPERATURE
1.
Press and release the
9
9
key.
2.
The “Hi” message will be displayed followed by the maximum temperature recorded.
3.
By pressing the
9
9
key or waiting for 5s the normal display will be restored.
4.4 HOW TO RESET THE MAX AND MIN TEMPERATURE RECORDED
To reset the stored temperature, when max or min temperature is displayed :
1.
Press SET key until “rST” label starts blinking.
N.B. After the installation RESET the temperature stored .
HOW TO SEE AND MODIFY THE SET POINT
1.
Push and immediately release the SET key: the display will show the Set point value;
2.
The SET LED start blinking;
3.
To change the Set value push the
9
9
or
8
8
arrows within 10s.
4.
To memorise the new set point value push the SET key again or wait 10s.
