dIXEL
Installing and Operating Instructions
1592026000
1592026000 XW20K GB R1.0 22.02.2008.doc
XW20K
1/5
XW20K AND T620 – V620 – CX620
1. GENERAL WARNING
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.
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
Model
XW20K
is microprocessor based controller suitable for applications on normal or medium
temperature refrigerating units. It has to be connected by means of a two-wire cable (
∅
1mm) at a
distance of up to 30 meters to the keyboard
T620
or
V620
or
CX620
.
It is provided with two relay outputs to control compressor and light. It is also provided with 3 NTC
probe inputs, one for temperature control, one to control the defrost end temperature of the evaporator
and the third to control condenser temperature or to display another temperature.
The HOT KEY output allows to connect the unit, by means of the external module XJ485-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
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
”.
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.
3.2
FAST FREEZING
When defrost is not in progress, it can be activated by holding the “
o
” key pressed for about 3
seconds. 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
“
o
” for 3 seconds.
DEFROST
Defrost is performed through a simple stop of the compressor. Parameter “
IdF
” controls the interval
between defrost cycles, while its length is controlled by parameter “
MdF
”.
3.3
DEFROST
Defrost is performed through a simple stop of the compressor. The parameters involved are: to control
the interval between defrost cycles (IdF), its maximum length (MdF) and two defrost modes: timed or
controlled by the evaporator’s probe (dFP and P3P). At the end of defrost dripping time is started, its
length is set in the FSt parameter. With FSt =0 the dripping time is disabled.
4. Relay 22-23 configuration- special functions
By means of the parameter
oA3
, it’s possible to configure the functions of the light relay (22-23), as
described in the following paragraphs:
OA3 = LIG: LIGHT RELAY (FACTORY SETTING)
By setting oA3 = Lig the relay will work as light relay, it is switched on and off by the light button on the
keyboard and is affected by status of the digital input when i1F = dor.
OA3 = CP2 2
ND
COMPRESSOR MANAGEMENT
By setting oA3 = cP2, the relay at terminals 22-23 will operate as “second compressor”. It will be
activated in parallel with the relay of the first compressor, with a possible delay set in the
AC1
parameter (seconds). Both the compressors are switched off at the same time.
OA3 = ONF: ON –OFF RELAY
By setting oA3 =onF, the relay will operate as “on-off” relay: it will be activated when the controller is
switched on and it will be switched off when the controller is in stand-by status.
OA3 = AUS: AUXILIARY RELAY
By setting oA3 = AUS, the relay 22-23 will work as auxiliary thermostat (I.E.. anti condensing heater).
Parameters involved:
-
ACH (cL, Ht):
Kind of regulation for the auxiliary relay:
Ht =
heating /
CL =
cooling
;
-
SAA (-50÷150)
Set point for auxiliary relay
-
SHy (0÷25.5°C)
Differential for auxiliary output.
o
With ACH = CL: aux relay
cut in
is SAA+SHy, cut out SAA.
o
With ACH = Ht: aux relay
cut in
is SAA-SHy, cut out SAA.
-
ArP (nP, P1, P2, P3, P4)
Probe for auxiliary relay
-
Sdd (n, Y)
Auxiliary output working during defrost
OA3 = ALR: ALARM RELAY
By setting oA3 = ALr the relay will work as alarm relay, it is switched on when an alarm happens.
Parameters involved:
-
tbA (n, y)
Alarm relay silencing
-
AoP (cL; oP)
Alarm relay polarity
OA3 = DB: NEUTRAL ZONE
By setting
oA3 = db
the controller will perform a
“neutral zone” regulation.
The heating element has to be connected to the
oA3 relay (22-23)
If the temperature increases and reaches set
point plus differential (
+HY
) the
compresso
r is
started and then turned off when the
temperature reaches the set point value again.
If the temperature decreases and reaches the
set point minus differential(
-HY
) the oA3 output
(
heater
) is switched on and then turned OFF
when the temperature reaches again the set
point.
5. Keyboards
T620
V620
CX620
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.
Switch ON and OFF the instrument.
KEY COMBINATIONS
+
To lock and unlock the keyboard.
