1592020670 XRi77CX-CH GB r1.1 15.10.2019 XRi77CX-CH 1/9
XRi77CX - XRi77CH
Digital controller for variable speed drive
FW 23.2
1. GENERAL WARNING....................................................................................................................1
2. GENERAL DESCRIPTION ............................................................................................................1
3. CONTROLLING LOADS ................................................................................................................1
4. PULL DOWN ..................................................................................................................................2
5. EVAPORATOR FAN CONTROL ...................................................................................................2
6. CONDENSER FAN CONTROL .....................................................................................................2
7. AUXILIARY REGULATOR .............................................................................................................2
8. DUAL MAP FEATURE ...................................................................................................................2
9. VARIABLE SPEED COMPRESSOR CONTROL ..........................................................................2
10. FRONT PANEL AND COMMANDS ..............................................................................................3
11. MAX & MIN TEMPERATURE MEMORIZATION ..........................................................................3
12. MAIN FUNCTIONS ........................................................................................................................3
13. PARAMETERS...............................................................................................................................3
14. DIGITAL INPUTS ...........................................................................................................................5
15. RS485 SERIAL LINE – FOR MONITORING SYSTEMS ..............................................................6
16. INSTALLATION AND MOUNTING ................................................................................................6
17. ELECTRICAL CONNECTIONS .....................................................................................................6
18. HOW TO USE THE HOT KEY .......................................................................................................6
19. ALARM SIGNALS ..........................................................................................................................6
20. TECHNICAL DATA ........................................................................................................................6
21. WIRINGS ........................................................................................................................................6
22. DEFAULT SETTING VALUES .......................................................................................................7
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 holidays 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
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.
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