1592020670 XRi77CX-CH GB r1.1 15.10.2019
XRi77CX-CH
1/9
XRi77CX - XRi77CH
Digital controller for variable speed drive
FW 23.2
FOR MONITORING SYSTEMS ..............................................................6
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 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.
2.
GENERAL DESCRIPTION
Model
XRi77CX-CH
, format 32x74mm, is microprocessor-based controller, suitable for applications on
medium or low temperature ventilated refrigerating units. It has four relay outputs to control
compressor, fan, defrost, which can be either electrical or reverse cycle (hot gas) and light
(configurable). It could be provided with a Real Time Clock which allows programming of up to 6 daily
defrost cycles, divided into ho
lidays and workdays. A “Day and Night” function with two different set
points is fitted for energy saving. It is also provided with up to four NTC probe inputs. The first probe is
used for temperature control. The second probe is used to control the defrost termination temperature
at the evaporator. One of the two digital inputs can operate as third temperature probe. The fourth
probe is used to control the condenser temperature (for condenser alarm management) or to display
a temperature.
The RS485 serial output allows connecting the unit to a network line (
ModBUS-RTU
compatible) such
as any Dixell monitoring units of X-WEB family. The HOT-KEY receptacle allows programming the
controller by using an HOTKEY programming device.
The instrument is fully configurable through special parameters that can be easily programmed through
the frontal keyboard.
3.
CONTROLLING LOADS
3.1
COMPRESSOR
The regulation is performed according to
the temperature measured by the
thermostat probe with a positive
differential (
HY
) over the set point: if the
temperature increases and reaches set
point plus differential, the compressor
will start. It will turn off as soon as 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
DEFROST
Two defrost modes are available through the
tdF
parameter: defrost through electrical heater
(
tdF=EL
) and hot gas defrost (
tdF=in
).
The defrost interval depends on the presence of the RTC (optional). The internal RTC is controlled by
means of the
EdF
parameter:
-
EdF=in:
the defrost is made every
idF
time
–
standard way for controller without RTC.
-
EdF=rtC:
the defrost is real time controlled, depending on the hours set in the parameters
Ld1...Ld6
(for workdays).
Other parameters are used to control defrosting cycles: the maximum length (
MdF
) and defrosting
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.
3.2.1
PRE-DEFROST
The par.
dAF
enable a pre-defrost phase. During this interval the regulation setpoint will be moved to
the value SET-1°C (or SET-1°F). The defrost phase starts as soon as the regulation temperature reach
the pre-defrost setpoint or when the
dAF
timer ends. This function is disable when
dAF=0
.
3.2.2
HOT GAS DEFROST
If
tdF=in
, the defrost phase will act as follow:
-
If
dSd>0
, the compressor output will be deactivated
-
At the end of
dSd
interval, the defrost output will be activated and timer
StC
will start
-
At the end of
StC
interval, the compressor output will be reactivated.
If
dSd=0
or
StC=0
, the relative functions will be disabled.
3.3
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 a defrost, there is a timed fan delay allowing for drip time, set by means of the
Fnd
parameter.
-
FnC=C_Y
,
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 is used to make sure circulation of air only if his temperature
is lower than set in
FSt
.
3.3.1
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.
3.3.2
CYCLIC 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.
3.4
RELAY CONFIGURATION (PAR. OA0, OA1, OA2, OA3)
The functioning of the configurable relays (terminals 1-2 and 1-7-8) can be set by the
oA1
and
oA2
parameters, according to the kind of application. In the following paragraph the possible setting:
3.4.1
LIGHT RELAY
With
oAx=LiG
the related relay operates as light output.
3.4.2
AUXILIARY RELAY
Relay activation by digital input 1 or digital input 2 (
oAx=AUS
,
i1F
or
i2F=AUS
): with
oAx=AUS
and
i1F
,
i2F=AUS
the AUX relay is switched on and off by digital inputs.
3.4.3
ON/OFF RELAY (OAX = ONF)
When
oAx=onF
, the related relay is activated when the controller is turned on and de-activated when
the controller is turned off.
3.4.4
NEUTRAL ZONE REGULATION
With
oAx=db
the related relay can control a heater element to perform a neutral zone action.
-
oAx
cut in =
SET-HY
-
oAx
cut out =
SET
3.4.5
ALARM RELAY
With
oAx=Alr
the related relay operates as alarm relay. It is activated every time an alarm happens.
Its status depends on the
tbA
parameter: if
tbA=Y
, the relay is silenced by pressing any key.
If
tbA=n
, the alarm relay stays on until the alarm condition recovers.
3.4.6
SECOND COMPRESSOR
If
oAx=CP2
, it will work as second compressor output. The anti-short cycle parameter
AC1
gives the
possibility to desynchronize the compressor activations.
3.4.7
SECOND DEFROST OUTPUT
If
oAx=dF2
, it will work as second defrost output.
NOTE:
It is also possible to manage 2 different and independent defrost by using special parameter
map. Please refer to Dixell to activate this function.
3.4.8
NIGHT BLINDS MANAGEMENT DURING ENERGY SAVING CYCLES
With
oAx=HES,
the related relay operates to manage the night blind: the relay is energised when the
energy saving cycle is activated by digital input or frontal button.
3.4.9
HEATER FOR WATER DRIPPING
If
oAx=Het
, the related output will work as heater for water dripping during and after any defrost.
