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3
Controlling Loads
3.1. Compressor
The regulation is performed according to the tem-
perature measured by the thermostat probe with a pos-
itive differential from the setpoint: if the temperature
increases and reaches setpoint plus the differential,
the compressor is started and then turned OFF when
the temperature reaches the setpoint value again.
Figure 3-1 - Compressor Temperature Regulation
In case of a fault in the thermostat probe, the start
and stop of the compressor are timed through param-
eters Con and CoF.
3.2. Defrost
With oA1 different from dEF and tdF = EL, the
controller performs a timed defrost, simply stopping
the compressor.
With oA1 = dEF, two defrost modes are available
through the tdF parameter: defrost through electrical
heater (tdF = EL) and hot gas defrost (tdF = in); in
this case, the second relay has to be set.
The defrost interval depends on the presence of the
RTC (optional). If the RTC is present, it 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 defrost is made in real time de-
pending on the hours set in the parameters
Ld1...Ld6 on workdays and in Sd1...Sd6 in holi-
days.
2 • XR35CX I&O Manual
Other parameters are used to control defrost cy-
cles: its maximum defrost duration (MdF) and two
defrost modes: time or controlled by the evaporator's
probe (P2P).
3.3. Second Relay
Configuration (PAR.
oA1; TERM. 1-7)
Depending on the kind of application, the function
of the second relay (terminals 1-7) can be set through
the oA1 parameter.
3.3.1. Defrost Relay (oA1 = dEF)
With oA1 = dEF, the relay functions as a defrost
relay. See Section 3.2., Defrost for more details.
3.3.2. Light Relay
With oA1 = Lig, the relay operates as light.
3.3.3. Auxiliary Relay (oA1 = AUS)
3.3.3.1. Relay Activation by Digital Input
(oA1 = AUS, i2F = AUS)
With oA1 = AUS and i2F = AUS, the relay 1-7 is
switched ON and OFF by a digital input.
3.3.3.2. Auxiliary Thermostat
An anti-condensing heater with the possibility of
switching it ON and OFF also by keyboard.
The function of the auxiliary relay can be config-
ured by means of the following parameters:
• ACH - Kind of regulation for the auxiliary relay:
Ht: heating; CL: cooling
• SAA - Setpoint for auxiliary relay
• SHy - Differential for auxiliary relay
• ArP - Probe for auxiliary relay
• Sdd - Auxiliary output OFF during defrost
NOTE: Set oA1 = AUS and ArP = nP (no probe
for auxiliary output). In this case the relay 1-7
can be activated only by digital input with i1F
or i2F = AUS.
3.3.4. ON/OFF Relay (oA1 = onF)
In this case, the relay is activated when the con-
troller is turned ON and deactivated when the control-
ler is turned OFF.
026-1203 Rev 3 03-FEB-2015
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