Digital controller with defrost and fan management
XR70CH

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 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 fai lure 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.
• Dixell Srl reserves the right to change the composition of its products, even without notice, ensuring the same and unchanged functionality.

GENERAL DESCRIPTION

Model XR70CH, 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, and defrost, which can be either electrical or reverse cycle (hot gas). The last one can be used as light, for alarm signalling or as auxiliary output. It is also provided with up to 4 NTC or PTC probe inputs, the first one for temperature control, the second one, to be located onto the evaporator, to control the defrost termination temperature and to managed the fan. The digital input can operate as third temperature probe. The fourth one, to connect to the HOT KEY terminals, is used to signal the condenser temperature alarm 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 Dixell 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 eas ily programmed through the keyboard.

CONTROLLING LOADS

3.1 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 DEFROST
Two defrost modes are available through the tdF parameter: defrost through electrical heater (tdF=EL) and hot gas defrost (tdF=in).
Other parameters are used to control the interval between defrost cycles (idF), its maximum length (MdF) and two defrost 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.
3.3 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 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 Cyclical 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.

FRONT PANEL COMMANDS

	To display target set point; in programming mode it selects a parameter or confirm an operation.
	(DEF) To start a manual defrost.
	(UP) To see the max stored temperature; in programming mode it browses the parameter codes or increases the displayed value.
	(DOWN) To see the min stored temperature; in programming mode it browses the parameter codes or decreases the displayed value.
	To switch the instrument on and off (when onF=oFF).
	To switch on and off the light (when oA3=LiG).

KEY COMBINATIONS:

	To lock & unlock the keyboard.
	To enter in programming mode.
	To return to the room temperature display.

4.1 USE OF LEDS
Each LED function is described in the following table.

LED	MODE	FUNCTION
	ON	Compressor enabled
	Flashing	Anti-short cycle delay enabled
	ON	Defrost enabled
	Flashing	Drip time in progress
	ON	Fans enabled
	Flashing	Fans delay after defrost in progress.
	ON	An alarm is occurring
	ON	Continuous cycle is running
ECO	ON	Energy saving enabled
	ON	Light on
AUX	ON	Auxiliary relay on
°C/°F	ON	Measurement unit
	Flashing	Programming phase

MAX & MIN TEMPERATURE MEMORIZATION

5.1 HOW TO: SEE THE MIN TEMPERATURE

1. Press and release the DOWN key.
2. The “Lo” message will be displayed followed by the minimum temperature recorded.
3. By pressing the DOWN key again or by waiting 5 sec the normal display will be restored.

5.2 HOW TO: SEE THE MAX TEMPERATURE

1. Press and release the UP key.
2. The “Hi” message will be displayed followed by the maximum temperature recorded.
3. By pressing the UP key again or by waiting 5 sec the normal display will be restored.

5.3 HOW TO: RESET THE MAX AND MIN TEMPERATURE RECORDED

1. Keep the SET key pressed more than 3 sec, while the max or min temperature is displayed. (“rSt” message will be displayed)
2. To confirm the operation the “rSt” message will start blinking and the normal temperature will be displayed.

MAIN FUNCTIONS

6.1 HOW TO: SEE THE SET POINT

1. Push and immediately release the SET key: the display will show the Set point value.
2. Push and immediately release the SET key or wait for 5 sec to display the probe value again.

6.2 HOW TO CHANGE THE SET POINT

1. Push the SET key more than 2 sec to change the Set point value.
2. The value of the set point will be displayed and the “°C” or “°F” LED will start blinking.
3. To change the Set value push the UP or DOWN arrows within 10 sec.
4. To save the new set point value, push the SET key again or wait for 10 sec.

6.3 HOW TO START A MANUAL DEFROST
Push the DEF key for more than 2 sec and a manual defrost will start.

6.4 HOW TO: CHANGE A PARAMETER VALUE
To change a parameter value, operate as follows:

1. Enter the Programming mode by pressing the SET+DOWN buttons for 3s (the °C or °F LED will start blinking).
2. Select the required parameter. Press the SET button to display its actual value.
3. Use UP or DOWN buttons to change its value.
4. Press SET button to store the new value and move to the following parameter.

To exit: Press SET + UP buttons or waiting for 15s without pressing any key.
NOTE: the set value is stored even when the procedure is exited by waiting for the time-out to expire.
6.5 THE HIDDEN MENU
The hidden menu includes all the parameters of the instrument.
6.5.1 HOW TO: ENTER THE HIDDEN MENU

1. Enter the Programming mode by pressing the SET+DOWN buttons for 3 sec (the °C or °F LED will start blinking).
2. Released the buttons and then push again the SET+DOWN buttons for more than 7s. The Pr2 label will be displayed immediately followed from the HY parameter. Now it is possible to browse the hidden menu.
3. Select the required parameter.
4. Press the SET button to display its value.
5. Use UP or DOWN to change its value.
6. Press SET to store the new value and move to the following parameter.

To exit: Press SET+DOWN or wait 15 sec without pressing a key.
NOTE1: if no parameter is present in Pr1 menu, after 3 sec the “noP” message will be displayed.
Keep the buttons pushed till the Pr2 message will be displayed.
NOTE2: the set value is stored even when the procedure is exited by waiting for the time-out to expire

6.5.2 HOW TO: MOVE A PARAMETER FROM THE HIDDEN MENU TO THE FIRST LEVEL AND VICEVERSA.
Each parameter present in the hidden menu (Pr2) can be moved into the user level (Pr1) by pressing SET+DOWN buttons. If a parameter is part of the user level, when showed in the hidden menu the decimal point will be lit.
6.6 HOW TO: LOCK THE KEYBOARD

1. Keep both UP and DOWN buttons pressed for more than 3 sec.
2. The “PoF” message will be displayed and the keyboard will 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 button is pressed more than 3 sec the “PoF” message will be displayed

6.7 HOW TO: UNLOCK THE KEYBOARD
Keep pressed together for more than 3 sec the UP and DOWN keys till the “Pon” message will be displayed.
6.8 THE CONTINUOUS CYCLE
When defrost is not in progress, it can be activated by holding the UP key pressed for about 3 sec.
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 UP for 3 sec.
6.9 THE ON/OFF FUNCTION
With “onF = oFF”, pushing the ON/OFF key, the instrument is switched off. The “OFF” 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 the normally closed contacts of the relays are always supplied and under voltage, even if the instrument is in stand by mode.

PARAMETERS

REGULATION

DISPLAY

DEFROST

FANS

ALARMS

CONDENSER TEMPERATURE ALARM

FOURTH RELAY

DIGITAL INPUTS

OTHER

DIGITAL INPUTS

The free voltage digital input is programmable by the i1F parameter.
8.1 GENERIC ALARM (I1F = EAL)
As soon as the digital input is activated the unit will wait for did time delay before signalling the EAL alarm message. The outputs statuses don’t change. The alarm stops just after the digital input is deactivated.
8.2 SERIOUS ALARM MODE (I1F = BAL)
When the digital input is activated, the unit will wait for did delay before signalling the CA alarm message. The relay outputs are switched OFF. The alarm will stop as soon as the digital input is deactivated.
8.3 PRESSURE SWITCH (I1F = PAL)
If during the interval time set by did parameter, the pressure switch has reached the number of activation of the nPS parameter; the CA pressure alarm message will be displayed. The compressor and the regulation are stopped. When the digital input is ON the compressor is always OFF. If the nPS activation in the did time is reached, switch off and on the instrument to restart normal regulation.
8.4 DOOR SWITCH INPUT (I1F = DOR)
It signals the door status and the corresponding relay output status through the odC parameter: no = normal (any change); FAn = Fan OFF; CPr = Compressor OFF; F_C = Compressor and fan OFF. Since the door is opened, after the delay time set through parameter doA, the door alarm is enabled, the display shows the message dA and the regulation restarts is rtr=YES. The alarm stops as soon as the external digital input is disabled again. With the door open, the high and low temperature alarms are disabled.
8.5 START DEFROST (I1F = DEF)
It starts a defrost if there are the right conditions. After the defrost is finished, the normal regulation will restart only if the digital input is disabled otherwise the ins trument will wait until the “MdF” safety time is expired.
8.6 INVERSION OF THE KIND OF ACTION: HEATING-COOLING (I1F=HTR)
This function allows to invert the regulation of the controller: from cooling to heating and viceversa.
8.7 ENERGY SAVING (I1F = ES)
The Energy Saving function allows to change the set point value as the result of the SET+ HES (parameter) sum. This function is enabled until the digi tal input is activated.
8.8 DIGITAL INPUT POLARITY
The digital input polarity depends on the i1P parameter.
i1P = CL: the input is activated by closing the contact.
i1P = oP: the input is activated by opening the contact

TTL SERIAL LINE – FOR MONITORING SYSTEMS

The TTL serial line, availabl e through the HOT KEY connector, allows to connect the instrument to a monitoring system ModBUS-RTU compatible such as the XWEB500.

X-REP OUTPUT – OPTIONAL

As optional, an X-REP can be connected to the instrument, trough the dedicated connector.To connect the X-REP to the instrument the following connectors must be used CAB51F(1m), CAB-52F(2m), CAB-55F(5m),

INSTALLATION AND MOUNTING

Instrument XR70CH shall be mounted on vertical panel, in a 29×71 mm hole, and fixed using the special bracket supplied.
The temperature range allowed for correct operation is 0 to 60°C.
Avoid places subject to strong vibrations, corrosive gases, excessive dirt or humidity. The same recommendations apply to probes. Let air circulate by the cooling holes.

ELECTRICAL CONNECTIONS

The instrument is provided with screw terminal block to connect cables with a cross section up to 2.5mm2 . Before connecting cables make sure the power supply complies with the instrument’s requirements. Separate the probe cables from the power supply cables, from the outputs and the power connections. Do not exceed the maximum current allowed on each relay, in case of heavier loads use a suitable external relay.
12.1 PROBE CONNECTION
The probes shall be mounted with the bulb upwards to prevent damages due to casual liquid infiltration. It is recommended to place the thermostat probe away from air streams to correctly measure the average room temperature. Place the defrost termination probe among the evaporator fins in the coldest place, where most ice is formed, far from heaters or from the warmest place during defrost, to prevent premature defrost termination.

USE THE HOT KEY

13.1 HOW TO: PROGRAM A HOT KEY FROM THE INSTRUMENT (UPLOAD)

1. Program one controller with the front keypad.
2. When the controller is ON, insert the “HOT-KEY” and push UP button; the “uPL” message appears followed a by a flashing “End” label.
3. Push SET button and the “End” will stop flashing.
4. Turn OFF the instrument, remove the “HOT-KEY” and then turn it ON again.

NOTE: the “Err” message appears in case of a failed programming operation. In this case push again button if you want to restart the upload again or remove the “HOT-KEY” to abort the operation.
13.2 HOW TO: PROGRAM AN INSTRUMENT USING A HOT KEY (DOWNLOAD)

1. Turn OFF the instrument.
2. Insert a pre-programmed “HOT-KEY” into the 5-PIN receptacle and then turn the Controller ON.
3. The parameter list of the “HOT-KEY” will be automatically downloaded into the Controller memory. The “doL” message will blink followed a by a flashing “End” label.
4. After 10 seconds the instrument will restart working with the new parameters.
5. Remove the “HOT-KEY”.

NOTE: the message “Err” is displayed for failed programming. In this case turn the unit off and then on if you want to restart the download again or remove the “HOT-KEY” to abort the operation.

ALARM SIGNALS

14.1 ALARM RECOVERY
Probe alarms P1”, “P2”, “P3” and “P4” start some seconds after the fault in the related probe; they automatically stop some seconds after the probe restarts normal operation. Check connection s before replacing the probe.
Temperature alarms “HA”, “LA” “HA2” and “LA2” automatically stop as soon as the temperature returns to normal values.
Alarms “EA” and “CA” (with i2F=bAL) recover as soon as the digital input is disabled.
Alarm “CA” (with i2F=PAL) recovers only by switching off and on the instrument.

TECHNICAL DATA

Housing: self extinguishing PC/PC+ABS
Case: frontal 38×80 mm; depth 62mm;
Mounting: panel mounting in a 71x29mm panel cut-out
Protection: NEMA – UL 50e: Indoor use only, type 1 enclosure
IEC 60529: Front panel: IP65; Rear housing: IP00
Power supply: according to the model
12VAC/DC, ±10%
110AC ±10%, 50/60Hz
230VAC ±10%, 50/60Hz
Overvoltage Category: III
Rated power: 3VA max
Rated impulse voltage: 4000V
Display: 3 digits, white LEDs, 19.0 mm high
Software class: A
Terminal blocks/Terminal Connections: Plug-in or screw terminal block, wire section between 1 and 2,5 mm2
Max tightening force: 0.5 N*m for 5,0mm pitch
Data storing: on the non-volatile memory (EEPROM).
Type of action: 1B
Pollution degree: 3
Ambient operating temperature: 0T60°C (ENEC) / -20T60°C (UL)
Shipping and storage temperature: -25T60°C
Inputs: Up to 4 NTC or PTC probes
Digital inputs: free voltage contact
Relay outputs: compressor SPST 8(3) A, 250VAC or SPST 16A 250VAC
Defrost: SPDT 8(3) A, 250VAC
Fan: SPST 5A, 250VAC
Aux: SPDT 8(3) A, 250VAC
Buzzer: optional
Relative humidity: 20 to 85% (no condensing)
Measuring and regulation range:
NTC probe: -40 to 110°C (-40 to 230°F)
PTC probe: -100 to 150°C (-148 to 302°F)
Resolution: 0.1°C or 1°C or 1°F (selectable)
Accuracy (ambient temp. 25°C): ±0.7°C ±1 digit
Accuracy (ambient temp. 25°C): ±0,7 °C ±1 digit
Purpose of control: operating control
Construction of control: incorporated control, intended to be used in Class I or Class II equipment.

CONNECTIONS

The X-REP output excludes the TTL output. It’s present in the following codes:
XR70CH- xx2xx, XR70CH –xx3xx;
16.1 XR70CH – 8A OR 16A COMP. RELAY – 230VAC OR 110VAC NOTE: The compressor relay is 8(3)A or 16(6)A according to the model.
24Vac supply: connect to the terminals 5 and 6.
16.2 XR70CH – 4 X 16A – 12VAC/DC

DEFAULT SETTING VALUES

Dixell S.r.l. – Z.1. Via dell’Industria,
27 – 32010 Pieve d’Alpago (BL) ITALY
Tel. +39.0437.9833 r.a.
Fax +39.0437.989313
EmersonClimate.com/Dixell 
dixell@emerson.com

Documents / Resources

Dixell XR70CH Digital Controller with Defrost and Fan Management [pdf] Instruction Manual XR70CH Digital Controller with Defrost and Fan Management, XR70CH, Digital Controller with Defrost and Fan Management, Controller with Defrost and Fan Management, Defrost and Fan Management, Fan Management

References

• User Manual