Digital controller with off cycle defrost
The regulation is perf ormed ac cordi ng to
the temperature measured by the
thermostat probe with a positive
ferential from the set point: if the
started and then turned off when the
LED
MODE
FUNCTION
ON
Compressor enabled
Flashing
Anti-short cycle delay enabled
ON
Defrost enabled
Flashing
Drip time in progress
ON
An alarm is occurring
ON
Continuous cycle is running
ON
Energy saving enabled
ON
Light on
°C/°F
ON
Measurement unit
°C/°F
Flashing
Programming phase
n
n
o
o
1. Push and immediatel y r elease the SET key: the di s pl ay w i l l s how t he S et
2. Push and immediately release the SET key or wait for 5 seconds to
Push the DEF key for more than 2 seconds and a manual defrost will start.
XW20LS
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
• Check the supply voltage is correct before connecting the inst r ument.
• Do not expose to water or moisture: use the controller only within the operating limits avoiding sudden
• Warning: disconnect all electr ical connections before any kind of maintenance.
• Fit the probe where it is not accessible by the End User. The instr um ent 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
• 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
• In case of applications in industrial environments, the use of mains filters (our mod. FT1) in parallel
2. GENERAL DESCRIPTION
Model XW20LS, format 38x185mm, is a digital thermostat with off cycle defrost designed for
refrigeration applications at normal temperature. It has 2 relay outputs to control compressor and light..
It could be provided wit h a Real Ti me Cl ock whic h al l ows pr ogr am m i ng of up to 6 dai l y def ros t c yc les,
divided into hol i day s and workdays. A “Day and Ni ght” func tion with two different set poi nt s i s fi t ted for
energy saving. It is also prov ided with up t o 2 N TC or P TC probe i nputs, t he firs t one for temperature
control, the second one, to be located onto the evaporator and to control the defrost termination
temperature. The digital input can operate as third temperature probe, to signal the condenser
temperature alarm or to display a temperature.
The HOT KEY output allows to connect the uni t, by means of the ext ernal module XJ 485-CX, to a
network line ModBUS-RTU compatible such as the dIXEL monitoring units of X-WEB family. It
allows to program the controller by means the HOT KEY programming keyboard.
The instrument is fully configurable through special parameters that can be easily programmed
through the keyboard.
3. CONTROLLING LOADS
3.1 COMPRESSOR
SAFETY PRECAUTIONS
temperature changes with high atmos pher ic humidity to prevent formation of condensation
address) with a detailed descript i on of the fault.
other, without crossing or i ntertwining.
with inductive loads could be useful.
: To display target set point; in programming mode i t selects a parameter or confirm an
operation.
(DEF) To start a manual defrost
(UP): To see the m ax. stored temperature; i n programming mode it brows es the parameter
codes or increases the displayed value.
(DOWN) To s ee the min stored temper ature; in programm ing mode it browses the parameter
codes or decreases the displayed value.
To switch the instrument off.
To switch the light.
KEY COMBINATIONS:
+
+ To enter in programming mode.
+
To lock & unlock the keyboard.
To return to the room temperature display.
4.3 USE OF LEDS
Each LED function is described in the following table.
5. MAX & MIN TEMPERATURE MEMORIZATION
5.1 HOW TO SEE THE MIN TEMPERATURE
1. Press and release the
key.
2. The “Lo” message will be displayed followed by the minimum temperature recorded.
3. By pressing the
key again or by waiting 5s the normal display will be restored.
5.2 HOW TO SEE THE MAX TEMPERATURE
1. Press and release the
key.
2. The “Hi” message will be displayed followed by the maximum temperature recorded.
3. By pressing the
key again or by waiting 5s the normal display will be restored.
dif
temperature increases and reaches set
point plus di fferential the compress or is
temperature reaches the set point val ue
again.
In case of fault i n the thermostat probe the start and stop of the compress or are timed through
parameters “COn” and “COF”.
3.2 DEFROST
Defrost is per formed through a simpl e stop of the compressor . The defrost interval depends on the
presence of the RTC (optional). If the RTC is present is controlled by means of parameter “EdF”:
- with EdF=in the defrost is made every “IdF” time – standard way for controller without RTC.
- with EdF = “rtc”, the defros t is made i n real tim e depending on the hour s set in the par ameters
Ld1..Ld6 on workdays and in Sd1…Sd6 in holidays;
Other parameters are used to control defrost cycles: i ts maximum length (MdF) and two defros t
modes: timed or controlled by the evaporator’s probe (P2P).
4. FRONT PANEL COMMANDS
4.1 STANDARD FRONTAL PANEL
1. Hold press the SET k ey for more than 3s , while the max . or min tem perature is dis played. (rSt
message will be displayed)
2. To confirm the operati on the “rSt” message starts blinking and the normal temperature wil l be
displayed.
6. MAIN FUNCTIONS
6.1 TO SET THE CURRENT TIME AND DAY (ONLY FOR INSTRUMENTS
WITH RTC)
When the instrument is switched on, it’s necessary to program the time and day.
1. Enter the Pr1 programming menu, by pushing the SET + n keys for 3s.
2. The rtc parameter is displayed. Push the SET key to enter the real time clock menu.
3. The Hur (hour) parameter is displayed.
4. Push the SET and set current hour by the UP and Down keys, then push SET to confirm
the value..
5. Repeat the same operations on the Min (minutes) and dAy (day) parameters.
To exit: Push SET+UP keys or wait for 15 sec without pushing any keys.
6.2 HOW TO SEE THE SET POINT
point value;
display the probe value again.
6.3 HOW TO CHANGE THE SET POINT
5.3 HOW TO RESET THE MAX AND MIN TEMPERATURE RECORDED
1. Push the SET key for more than 2 seconds to change the Set point value;
4.2 STEEL FINISHING
2. The value of the set point will be displayed and the “°C” or “°F” LED starts blinking;
3. To change the Set value push the o or n arrows within 10s.
4. To memorise the new set point value push the SET key again or wait 10s.
6.4 HOW TO START A MANUAL DEFROST
1592027320 XW20LS RTC GB r1.0 18.03.2015 XW20LS 1/5
6.5 HOW TO CHANGE A PARAMETER VALUE
To change the parameter’s value operate as follows:
1. Enter the Programm ing mode by pres sing the Set + n keys for 3s (the “°C” or “°F” LED starts
n
o
With “onF = oFF”, pushing the ON/OFF key, the ins trument is swit ched off. The “OFF”
blinking).
2. Select the required parameter. Press the “SET” key to display its value
3. Use “UP” or “DOWN” to change its value.
4. Press “SET” to store the new value and move to the following parameter.
To exit: Press SET + UP or wait 15s without pressing a key.
NOTE: the set value is stored even when the procedure is exited by waiting the time-out to expire.
6.6 THE HIDDEN MENU
The hidden menu Includes all the parameters of the instrument.
6.6.1 HOW TO ENTER THE HIDDEN MENU
1. Enter the Programm ing mode by pres sing the Set + n keys for 3s (the “°C” or “°F” LED starts
blinking).
2. Releas ed the keys, then push again the Set+n keys for more than 7s. The Pr2 label will be
displayed immediately followed from the HY parameter.
NOW YOU ARE IN THE HIDDEN MENU.
3. Select the required parameter.
4. Press the “SET” key to display its value
5. Use o or n to change its value.
6. Press “SET” to store the new value and move to the following parameter.
To exit: Press SET + o or wait 15s without pressing a key.
NOTE1: i f none parameter is pres ent in Pr 1, after 3s the “noP ” message is displ ayed. Keep the k eys
pushed till the Pr2 message is displayed.
NOTE2: the set value is stored even when the procedure is exited by waiting the time-out to expire.
6.6.2 HOW TO MOVE A PARAMETER FROM THE HIDDEN MENU TO THE
FIRST LEVEL AND VIC EVER SA.
Each parameter pres ent i n the HI DDE N M E NU can be r em ov ed or put into “THE FIRST LEVE L” (us er
level) by pressing “SET +
In HIDDEN MENU when a parameter is present in First Level the decimal point is on.
”.
6.7 HOW TO LOCK THE KEYBOARD
1. Keep pressed for more than 3 s the UP + DOWN keys.
2. The “POF” message will be displayed and the keyboard wil l 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 key is pressed more than 3s the “POF” message will be displayed.
6.8 TO UNLOCK THE KEYBOARD
Keep pressed together for more than 3s the o and n keys, till the “Pon” message will be
displayed.
6.9 THE CONTINUOUS CYCLE
When defrost is not in progress, i t can be activated by holding the “o” key pressed for about 3
seconds. The compressor operat es to maintain the “ccS” set poi nt for the ti me set through t he “CCt”
parameter. The cycl e can be term inated before the end of the s et tim e using the sam e activ ation key
“
” for 3 seconds.
6.10 THE ON/OFF FUNCTION
message is displayed. In this configuration, the regulation is disabled.
To switch the instrument on, push again the ON/OFF key.
WARNING: Loads connected to t he nor mally clo sed cont acts of t he r elays are always supplied
and under voltage, even if the instrument is in stand by mode.
7. PARAMETERS
rtc Real time clock menu (only for controller with RTC): to set the time and date and defrost start
time.
REGULATION
Hy Differential: (0,1 ÷ 25,5°C / 1÷ 255 °F) Int erventi on dif ferenti al f or s et poi nt. C om pr ess or Cut IN i s
Set Point + differential (Hy ). Compressor Cut OUT is when the temperature reac hes the set
point.
LS Minimum set point: (- 50°C÷SET/-58°F÷SET): Sets the minimum value for the set point.
US Maximum set point: (SET÷110°C/ SET÷230°F). Set the maximum value for set point.
Ot Thermostat probe calibration: (-12.0÷12.0°C; -120÷120°F) allows to adjust possibl e offset of
the thermostat probe.
P2P Evaporator probe presence: n= not present: y= present:
OE Evaporator probe calibration: (-12.0÷12.0°C; -120÷120°F) . allows to adjust pos sible offset of
the evaporator probe.
P3P Third probe pr esence (P3): n= not pres ent :, t he ter m i nals operate as digital i nput .; y= present:,
the terminals operate as third probe.
O3 Third probe calibration (P3): (-12.0÷12.0°C; -120÷120°F). allows to adjust possible offset of the
third probe.
OdS Outputs activat ion delay at start up: (0÷255mi n) Thi s funct ion i s enabl ed at the ini tial star t up
of the instrument and inhibits any output activation for the period of time set in the parameter.
AC Anti-short cycle delay: (0÷ 50 min) minimum inter val between the compressor stop and the
following restart.
rtr Percentage of the seco nd and f ir st p r ob e for regulation (0÷100; 100 = P1, 0 = P2 ): it allows
to set the regulation according to the percentage of the firs t and second probe, as for the
following formula (rtr(P1-P2)/100 + P2).
CCt Compressor ON time during continuous cycle: (0.0÷24.0h; res. 10min) Allows to set the
length of the continuous cyc le: compr essor s tays on without interr uption for the CCt tim e. Can be
used, for instance, when the room is filled with new products.
CCS Set point for continuous cycle: (-50÷150°C) it sets the set point used dur ing the continuous
cycle.
COn Compressor ON time with faulty probe: (0÷255 min) tim e during which the compr essor is
active in case of faulty thermostat probe. With COn=0 compressor is always OFF.
COF Compressor OFF time with faulty probe: (0÷255 min) time duri ng which the compressor is
OFF in case of faulty thermostat probe. With COF=0 compressor is always active.
CH Type of action: CL = cooling; Ht = heating.
1592027320 XW20LS RTC GB r1.0 18.03.2015 XW20LS 2/5
DISPLAY
CF Temperature measurement unit: °C=Celsius; °F=Fahrenheit. WARNING: When the
measurement unit is changed the S ET point and t he values of t he 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 = NOT SET IT, SET = set point; dtr = percentage of visualization.
rEd X- REP display (optional): (P1; P 2, P3, P4, S ET , dtr): i t s el ec ts w hi c h pr obe i s di s pl ay ed by X-
REP: P1 = Therm ostat probe; P2 = Evaporator probe; P3 = Third probe(only for m odel wi th this
option enabled); P4 = NOT SET IT, SET = set point; dtr = percentage of visualization.
dLy Display delay: (0 ÷20.0m ; resul. 10s) when the temperature increases, the display is updated of
1 °C/1°F after this time.
dtr Percentage of th e second and first probe for visualization when Lod = d tr (0÷100; 100 =
P1, 0 = P2 ): if Lod = dtr it allows to s et t he visualization acc or di ng t o the per c entage of t he fir s t
and second probe, as for the following formula (dtr(P1-P2)/100 + P2).
DEFROST
EdF Defrost mode (only for controller with RTC): rtc = Real Time Cl ock mode. Defrost time
follows Ld1÷Ld6 parameters on workdays and Sd1÷Sd6 on holidays.
in = interval mode. The defrost starts when the time “Idf” is expired.
dFP Probe selection for defrost termination: nP = no probe; P1 =thermostat probe; P2 =
evaporator probe; P3 =configurable probe; P4 = NOT SET IT.
dtE Defro st terminat ion temperat ure: (-50÷50 °C/ -58÷122° F) (Enabl ed only when E dF=Pb) s ets
the temperature measured by the evaporator probe, which causes the end of defrost.
IdF Interval betw een defr ost cycles: ( 0÷ 120h) Det erm ines the time interv al betw een the begi nni ng
of two defrost cycles.
MdF (Maximum) length for defrost: (0÷255min) When P2P = n, (not ev aporator probe: timed
defrost) it set s the defr os t dur at i on, when P2P = y ( defr os t end bas ed on tem per atur e) i t s ets the
maximum length for defrost.
dFd Temperature displayed during defrost: (rt = real temperat ur e; it = temperature at defrost start;
SEt = set point; dEF = “dEF” label)
dAd MAX disp lay delay after defrost: (0÷255m in). Sets the maximum ti me between the end of
defrost and the restarting of the real room temperature display.
ALARMS
ALP Pr obe selecti on for alarm: nP = no pr obe, the temperatur e alarms are disabled; P1 = P robe 1
(Thermostat probe); P 2 = Probe 2 ( evaporator pr obe); P3 = P robe 3 (dis play pr obe); P4 = NOT
SET IT.
ALC Temperature alarms configuration: (Ab; rE)
Ab= absolute temperature: alarm temperature is given by the ALL or ALU values. rE =
temperature alarms are referred to the set point. Temperature alarm is enabled when the
temperature exceeds the “SET+ALU” or “SET-ALL” values.
ALU MAXIMUM temperature alar m: (SET÷110°C ; SET÷230°F) when thi s temperature is reached
the alarm is enabled, after the “ALd” delay time.
ALL Minimum temp erature alarm: ( -50.0 ÷ SET °C; -58÷ 230°F when this temper ature is reached
the alarm is enabled, after the “ALd” delay time.
AFH Differential for temper atur e alar m reco very: (0,1÷25,5°C; 1÷45°F) Int erv ent i on di f fer enti al for
recovery of temperature alarm.
ALd Temperature alarm delay: (0÷255 min) time interval between the detection of an alarm
condition and alarm signalling.
dAo Exclusion of temperat ure alar m at start-up: (from 0.0 min to 23.5h) time i nterval between the
detection of the temperature alarm condition after instrument power on and alarm signalling.
CONDENSER TEMPERATURE ALARM
AP2 Probe selection for t emperatur e alarm of condenser: nP = no probe; P1 =therm ostat pr obe;
P2 = evaporator probe; P3 =configurable probe; P4 = NOT SET IT.
AL2 Low temperatur e alarm of condenser: (-55÷150°C) when this temper ature i s reac hed the LA2
alarm is signalled, possibly after the Ad2 delay.
Au2 High temperatur e alar m of co nd enser: (-55÷150°C) when this tem per atur e i s r eac hed the HA 2
alarm is signalled, possibly after the Ad2 delay.
AH2 Differential for temperature condenser alarm recovery: (0,1÷25,5°C; 1÷45°F)
Ad2 Condenser temperature alarm delay: (0÷ 255 min) time int erval between the detection of the
condenser alarm condition and alarm signalling.
dA2 Condenser temperature alarm exclusion at start up: (from 0.0 min to 23.5h, res. 10min)
bLL Compressor off with low temperature alarm of condenser: n = no: c ompressor keeps on
working; Y = yes, compr essor is switched off till the alarm is present, in any case regulati on
restarts after AC time at minimum.
AC2 Compressor off with high temperature alarm of condenser: n = no: compressor k eeps on
working; Y = yes, com pressor is swit ched off till the alarm is present, in any case regul ation
restarts after AC time at minimum.
DIGITAL INPUT
i1P Digital input polarity: oP: the digital input i s activated by openi ng the contact; CL: the digi tal
input is activated by closing the contact.
i1F Digital input configuration: EAL= external alarm: “EA ” message is displayed; bAL= s erious
alarm “CA” message i s displayed. PAL= pressure s witch alarm, “CA” message is display ed;
dor= door switch funct ion; dEF= activation of a defrost cycle; AUS=not enabl ed; Htr= kind of
action invers i on ( c ool i ng – heating); FAn= not set it; ES= Energy s av i ng; HdF = Holiday defrost
(enable only with RTC); onF = to switch the controller off.
did (0÷255 min) with i1F= EAL or i1F = bAL digital input alarm delay (1-3): delay between the
detection of the external alarm condition and its signalling.
with i1F= dor: door open signalling delay
with i1F= PAL: time for pressure switch function: time interv al to c alculate the number of the
pressure switch activation.
nPS Pressure swi tch number : (0
interval, before signalling the alarm event (i1F= PAL).
If the nPS activation in the did t i me is r each ed , swi t ch o ff an d o n t h e in st r um ent t o rest ar t
normal regulation.
odc Compressor status when open door: no, Fan = normal; CPr, F_C = Compressor OFF.
rrd Outpu ts restart aft er doA alarm: n o= outputs not affected by the doA alar m; yES = outputs
restart with the doA alarm.
HES Temperature increase during the Energy Saving cycle:
(-30,0°C
TO SET CURRENT TIME AND WEEKLY HOLIDAYS (ONLY FOR MODELS WITH RTC)
Hur Current hour (0 ÷ 23 h)
÷30,0°C) it sets the increasing value of the set point during the Energy Saving cycle.
÷15) Number of ac tiv ation of the pres sure s wit ch, duri ng the “did”
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